Lithium reacts with nitrogen gas according to the

Problem 24E Deviations from the ideal gas law are often observed at high pressure and low temperature. Explain this in light of kinetic molecular theory.

Problem 25E The pressure in Denver, Colorado (elevation 5280 ft), averages about 24.9 in Hg. Convert this pressure to each indicated unit. a. atm b . mmHg c. psi d . Pa

Problem 26E The pressure on top of Mt. Everest averages about 235 mmHg. Convert this pressure to each indicated unit. a . torr b . psi c . in Hg d . atm

Problem 27E The North American record for highest recorded barometric pressure is 31.85 in Hg, set in 1989 in Northway, Alaska. Convert this pressure to each indicated unit. a . mmHg b . atm c . torr d . kPa (kilopascals)

A sample of Xe takes 75 seconds to effuse out of a container. An unknown gas takes 37 seconds to effuse out of the identical container under identical conditions. What is the most likely identity of the unknown gas? a) He b) O2 c) Br2 d) Kr

Problem 14E How does the density of a gas depend on temperature? Pressure? How does it depend on the molar mass of the gas?

Consider the generic reaction: 2 A(g) + B(g) ? 2 C(g) . If a f ask initially contains 1.0 atm of A and 1.0 atm of B, what will be the pressure in the f ask if the reaction proceeds to completion? (Assume constant volume and temperature.) a) 1.0 atm b) 1.5 atm c) 2.0 atm d) 3.0 atm

Problem 15E What is partial pressure? What is the relationship between the partial pressures of each gas in a sample and the total pressure of gas in the sample?

Rank the gases Ar, N2, CH4, and C2H6 in order of increasing density at STP. a) CH4 < C2H6 < N2 < Ar b) CH4 < N2 < Ar < C2H6 c) Ar < C2H6 < N2 < CH4 d) CH4 < N2 < C2H6 < Ar

Problem 23E Explain the difference between diffusion and effusion. How is the effusion rate of a gas related to its molar mass?

Problem 1E Explain this statement in your own words and give an example. The properties of the substances around us depend on the atoms and molecules that compose them.

Problem 2E Explain what happens when you inhale. What forces air into your lungs?

Problem 3E Explain what happens when you exhale. What forces air out of your lungs?

Problem 4E What are the common units of pressure? List them in order of smallest to largest unit.

Problem 5E What is a manometer? How does it measure the pressure of a sample of gas?

Problem 6E Summarize each of the simple gas laws (Boyle’s law, Charles’s law, and Avogadro’s law). For each law, explain the relationship between the two variables and also state which variables must be kept constant.

Problem 7E Explain the source of ear pain experienced due to a rapid change in altitude.

Problem 8E Explain why scuba divers should never hold their breath as they ascend to the surface.

Problem 9E Why is it impossible to breathe air through an extra-long snorkel (greater than a couple of meters) while swimming underwater?

Problem 13E Define molar volume and give its value for a gas at STP.

Problem 12E Explain how the ideal gas law contains within it the simple gas laws (show an example).

Problem 16E Why do deep-sea divers breathe a mixture of helium and oxygen?

Problem 17E When a gas is collected over water, is the gas pure? Why or why not? How can the partial pressure of the collected gas be determined?

Problem 18E If a reaction occurs in the gas phase at STP, the mass of a product can be determined from the volumes of reactants. Explain.

Problem 19E What are the basic postulates of kinetic molecular theory? How does the concept of pressure follow from kinetic molecular theory?

Problem 21E How is the kinetic energy of a gas related to temperature? How is the root mean square velocity of a gas related to its molar mass?

Problem 20E Explain how Boyle’s law, Charles’s law, Avogadro’s law, and Dalton’s law all follow from kinetic molecular theory.

Consider the following gaseous sample in a cylinder fitted with a movable piston. Initially there are n moles of the gas at temperature T, pressure P, and volume V. Choose the cylinder that correctly represents the gas after each of the following changes. (1) The pressure on the piston is tripled at constant n and T. (2) The temperature is doubled at constant n and P. (3) n moles of another gas are added at constant T and P. (4) T is halved and pressure on the piston is reduced to a quarter of its original value. (a) (b) (c)

A gas occupying a volume of 725 mL at a pressure of 0.970 atm is allowed to expand at constant temperature until its pressure reaches 0.541 atm. What is its final volume?

At 46C a sample of ammonia gas exerts a pressure of 5.3 atm. What is the pressure when the volume of the gas is reduced to one-tenth (0.10) of the original value at the same temperature?

The volume of a gas is 5.80 L, measured at 1.00 atm. What is the pressure of the gas in mmHg if the volume is changed to 9.65 L? (The temperature remains constant.)

A sample of air occupies 3.8 L when the pressure is 1.2 atm. (a) What volume does it occupy at 6.6 atm? (b) What pressure is required in order to compress it to 0.075 L? (The temperature is kept constant.)

A 36.4-L volume of methane gas is heated from 25C to 88C at constant pressure. What is the final volume of the gas?

Under constant-pressure conditions a sample of hydrogen gas initially at 88C and 9.6 L is cooled until its final volume is 3.4 L. What is its final temperature?

Ammonia burns in oxygen gas to form nitric oxide (NO) and water vapor. How many volumes of NO are obtained from one volume of ammonia at the same temperature and pressure?

Molecular chlorine and molecular fluorine combine to form a gaseous product. Under the same conditions of temperature and pressure it is found that one volume of Cl2 reacts with three volumes of F2 to yield two volumes of the product. What is the formula of the product?

List the characteristics of an ideal gas. Write the ideal gas equation and also state it in words. Give the units for each term in the equation

Use Equation (5.9) to derive all the gas laws.

What are standard temperature and pressure (STP)? What is the significance of STP in relation to the volume of 1 mole of an ideal gas?

Why is the density of a gas much lower than that of a liquid or solid under atmospheric conditions? What units are normally used to express the density of gases?

A sample of nitrogen gas kept in a container of volume 2.3 L and at a temperature of 32C exerts a pressure of 4.7 atm. Calculate the number of moles of gas present.

Given that 6.9 moles of carbon monoxide gas are present in a container of volume 30.4 L, what is the pressure of the gas (in atm) if the temperature is 62C?

What volume will 5.6 moles of sulfur hexafluoride (SF6) gas occupy if the temperature and pressure of the gas are 128C and 9.4 atm?

A certain amount of gas at 25C and at a pressure of 0.800 atm is contained in a glass vessel. Suppose that the vessel can withstand a pressure of 2.00 atm. How high can you raise the temperature of the gas without bursting the vessel?

A gas-filled balloon having a volume of 2.50 L at 1.2 atm and 25C is allowed to rise to the stratosphere (about 30 km above the surface of Earth), where the temperature and pressure are 223C and 3.00 3 1023 atm, respectively. Calculate the final volume of the balloon.

The temperature of 2.5 L of a gas initially at STP is raised to 250C at constant volume. Calculate the final pressure of the gas in atm

The pressure of 6.0 L of an ideal gas in a flexible container is decreased to one-third of its original pressure, and its absolute temperature is decreased by one-half. What is the final volume of the gas?

A gas evolved during the fermentation of glucose (wine making) has a volume of 0.78 L at 20.1C and 1.00 atm. What was the volume of this gas at the fermentation temperature of 36.5C and 1.00 atm pressure?

An ideal gas originally at 0.85 atm and 66C was allowed to expand until its final volume, pressure, and temperature were 94 mL, 0.60 atm, and 45C, respectively. What was its initial volume?

Calculate its volume (in liters) of 88.4 g of CO2 at STP

A gas at 772 mmHg and 35.0C occupies a volume of 6.85 L. Calculate its volume at STP.

Dry ice is solid carbon dioxide. A 0.050-g sample of dry ice is placed in an evacuated 4.6-L vessel at 30C. Calculate the pressure inside the vessel after all the dry ice has been converted to CO2 gas

At STP, 0.280 L of a gas weighs 0.400 g. Calculate the molar mass of the gas.

At 741 torr and 44C, 7.10 g of a gas occupy a volume of 5.40 L. What is the molar mass of the gas?

Ozone molecules in the stratosphere absorb much of the harmful radiation from the sun. Typically, the temperature and pressure of ozone in the stratosphere are 250 K and 1.0 3 1023 atm, respectively. How many ozone molecules are present in 1.0 L of air under these conditions?

Assuming that air contains 78 percent N2, 21 percent O2, and 1 percent Ar, all by volume, how many molecules of each type of gas are present in 1.0 L of air at STP?

A 2.10-L vessel contains 4.65 g of a gas at 1.00 atm and 27.0C. (a) Calculate the density of the gas in grams per liter. (b) What is the molar mass of the gas?

Calculate the density of hydrogen bromide (HBr) gas in grams per liter at 733 mmHg and 46C.

A certain anesthetic contains 64.9 percent C, 13.5 percent H, and 21.6 percent O by mass. At 120C and 750 mmHg, 1.00 L of the gaseous compound weighs 2.30 g. What is the molecular formula of the compound?

A compound has the empirical formula SF4. At 20C, 0.100 g of the gaseous compound occupies a volume of 22.1 mL and exerts a pressure of 1.02 atm. What is the molecular formula of the gas?

What pressure will be required for neon at 30C to have the same density as nitrogen at 20C and 1.0 atm?

The density of a mixture of fluorine and chlorine gases is 1.77 g/L at 14C and 0.893 atm. Calculate the mass percent of the gases.

Consider the formation of nitrogen dioxide from nitric oxide and oxygen: 2NO(g) 1 O2(g) 2NO2(g) If 9.0 L of NO are reacted with excess O2 at STP, what is the volume in liters of the NO2 produced?

Methane, the principal component of natural gas, is used for heating and cooking. The combustion process is CH4(g) 1 2O2(g) CO2(g) 1 2H2O(l) If 15.0 moles of CH4 are reacted, what is the volume of CO2 (in liters) produced at 23.0C and 0.985 atm?

When coal is burned, the sulfur present in coal is converted to sulfur dioxide (SO2), which is responsible for the acid rain phenomenon. S(s) 1 O2(g) SO2(g) If 2.54 kg of S are reacted with oxygen, calculate the volume of SO2 gas (in mL) formed at 30.5C and 1.12 atm

In alcohol fermentation, yeast converts glucose to ethanol and carbon dioxide: C6H12O6(s) 2C2H5OH(l) 1 2CO2(g) If 5.97 g of glucose are reacted and 1.44 L of CO2 gas are collected at 293 K and 0.984 atm, what is the percent yield of the reaction?

A compound of P and F was analyzed as follows: Heating 0.2324 g of the compound in a 378-cm3 container turned all of it to gas, which had a pressure of 97.3 mmHg at 77C. Then the gas was mixed with calcium chloride solution, which turned all of the F to 0.2631 g of CaF2. Determine the molecular formula of the compound

A quantity of 0.225 g of a metal M (molar mass 5 27.0 g/mol) liberated 0.303 L of molecular hydrogen (measured at 17C and 741 mmHg) from an excess of hydrochloric acid. Deduce from these data the corresponding equation and write formulas for the oxide and sulfate of M.

What is the mass of the solid NH4Cl formed when 73.0 g of NH3 are mixed with an equal mass of HCl? What is the volume of the gas remaining, measured at 14.0C and 752 mmHg? What gas is it?

Dissolving 3.00 g of an impure sample of calcium carbonate in hydrochloric acid produced 0.656 L of carbon dioxide (measured at 20.0C and 792 mmHg). Calculate the percent by mass of calcium carbonate in the sample. State any assumptions.

Calculate the mass in grams of hydrogen chloride produced when 5.6 L of molecular hydrogen measured at STP react with an excess of molecular chlorine gas

Ethanol (C2H5OH) burns in air: C2H5OH(l) 1 O2(g) CO2(g) 1 H2O(l) Balance the equation and determine the volume of air in liters at 35.0C and 790 mmHg required to burn 227 g of ethanol. Assume that air is 21.0 percent O2 by volume

(a) What volumes (in liters) of ammonia and oxygen must react to form 12.8 L of nitric oxide according to the equation at the same temperature and pressure? 4NH3(g) 1 5O2(g) 4NO(g) 1 6H2O(g) (b) What volumes (in liters) of propane and water vapor must react to form 8.96 L of hydrogen according to the equation at the same temperature and pressure? C3H8(g) 1 3H2O(g) 3CO(g) 1 7H2(g)

A 4.00-g sample of FeS containing nonsulfide impurities reacted with HCl to give 896 mL of H2S at 14C and 782 mmHg. Calculate mass percent purity of the sample.

State Daltons law of partial pressures and explain what mole fraction is. Does mole fraction have units?

A sample of air contains only nitrogen and oxygen gases whose partial pressures are 0.80 atm and 0.20 atm, respectively. Calculate the total pressure and the mole fractions of the gases.

A mixture of gases contains 0.31 mol CH4, 0.25 mol C2H6, and 0.29 mol C3H8. The total pressure is 1.50 atm. Calculate the partial pressures of the gases

A 2.5-L flask at 15C contains a mixture of N2, He, and Ne at partial pressures of 0.32 atm for N2, 0.15 atm for He, and 0.42 atm for Ne. (a) Calculate the total pressure of the mixture. (b) Calculate the volume in liters at STP occupied by He and Ne if the N2 is removed selectively

Dry air near sea level has the following composition by volume: N2, 78.08 percent; O2, 20.94 percent; Ar, 0.93 percent; CO2, 0.05 percent. The atmospheric pressure is 1.00 atm. Calculate (a) the partial pressure of each gas in atm and (b) the concentration of each gas in moles per liter at 0C. (Hint: Because volume is proportional to the number of moles present, mole fractions of gases can be expressed as ratios of volumes at the same temperature and pressure.)

A mixture of helium and neon gases is collected over water at 28.0C and 745 mmHg. If the partial pressure of helium is 368 mmHg, what is the partial pressure of neon? (Vapor pressure of water at 28C 5 28.3 mmHg.)

A piece of sodium metal reacts completely with water as follows: 2Na(s) 1 2H2O(l) 2NaOH(aq) 1 H2(g) The hydrogen gas generated is collected over water at 25.0C. The volume of the gas is 246 mL measured at 1.00 atm. Calculate the number of grams of sodium used in the reaction. (Vapor pressure of water at 25C 5 0.0313 atm.)

A sample of zinc metal reacts completely with an excess of hydrochloric acid: Zn(s) 1 2HCl(aq) ZnCl2(aq) 1 H2(g) The hydrogen gas produced is collected over water at 25.0C using an arrangement similar to that shown in Figure 5.15. The volume of the gas is 7.80 L, and the pressure is 0.980 atm. Calculate the amount of zinc metal in grams consumed in the reaction. (Vapor pressure of water at 25C 5 23.8 mmHg.)

Helium is mixed with oxygen gas for deep-sea divers. Calculate the percent by volume of oxygen gas in the mixture if the diver has to submerge to a depth where the total pressure is 4.2 atm. The partial pressure of oxygen is maintained at 0.20 atm at this depth.

A sample of ammonia (NH3) gas is completely decomposed to nitrogen and hydrogen gases over heated iron wool. If the total pressure is 866 mmHg, calculate the partial pressures of N2 and H2.

Consider the three gas containers shown here. All of them have the same volume and are at the same temperature. (a) Which container has the smallest mole fraction of gas A (blue sphere)? (b) Which container has the highest partial pressure of gas B (green sphere)? (i) (ii) (iii)

The volume of the box on the right is twice that of the box on the left. The boxes contain helium atoms (red) and hydrogen molecules (green) at the same temperature. (a) Which box has a higher total pressure? (b) Which box has a lower partial pressure of helium?

What are the basic assumptions of the kinetic molecular theory of gases? How does the kinetic molecular theory explain Boyles law, Charles law, Avogadros law, and Daltons law of partial pressures?

What does the Maxwell speed distribution curve tell us? Does Maxwells theory work for a sample of 200 molecules? Explain

Which of the following statements is correct? (a) Heat is produced by the collision of gas molecules against one another. (b) When a gas is heated, the molecules collide with one another more often.

What is the difference between gas diffusion and effusion? State Grahams law and define the terms in Equation (5.17).

Compare the root-mean-square speeds of O2 and UF6 at 65C.

The temperature in the stratosphere is 223C. Calculate the root-mean-square speeds of N2, O2, and O3 molecules in this region.

The average distance traveled by a molecule between successive collisions is called mean free path. For a given amount of a gas, how does the mean free path of a gas depend on (a) density, (b) temperature at constant volume, (c) pressure at constant temperature, (d) volume at constant temperature, and (e) size of the atoms?

At a certain temperature the speeds of six gaseous molecules in a container are 2.0 m/s, 2.2 m/s, 2.6 m/s, 2.7 m/s, 3.3 m/s, and 3.5 m/s. Calculate the rootmean-square speed and the average speed of the molecules. These two average values are close to each other, but the root-mean-square value is always the larger of the two. Why?

Based on your knowledge of the kinetic theory of gases, derive Grahams law [Equation (5.17)].

The 235U isotope undergoes fission when bombarded with neutrons. However, its natural abundance is only 0.72 percent. To separate it from the more abundant 238U isotope, uranium is first converted to UF6, which is easily vaporized above room temperature. The mixture of the 235UF6 and 238UF6 gases is then subjected to many stages of effusion. Calculate the separation factor, that is, the enrichment of 235U relative to 238U after one stage of effusion.

A gas evolved from the fermentation of glucose is found to effuse through a porous barrier in 15.0 min. Under the same conditions of temperature and pressure, it takes an equal volume of N2 12.0 min to effuse through the same barrier. Calculate the molar mass of the gas and suggest what the gas might be.

Nickel forms a gaseous compound of the formula Ni(CO)x. What is the value of x given the fact that under the same conditions of temperature and pressure, methane (CH4) effuses 3.3 times faster than the compound?

Cite two pieces of evidence to show that gases do not behave ideally under all conditions.

Under what set of conditions would a gas be expected to behave most ideally? (a) High temperature and low pressure, (b) high temperature and high pressure, (c) low temperature and high pressure, (d) low temperature and low pressure.

Shown here are plots of PVyRT against P for one mole of a nonideal gas at two different temperatures. Which curve is at the higher temperature? P PV RT 1.0

(a) A real gas is introduced into a flask of volume V. Is the corrected volume of the gas greater or less than V? (b) Ammonia has a larger a value than neon does (see Table 5.4). What can you conclude about the relative strength of the attractive forces between molecules of ammonia and between atoms of neon?

Using the data shown in Table 5.4, calculate the pressure exerted by 2.50 moles of CO2 confined in a volume of 5.00 L at 450 K. Compare the pressure with that predicted by the ideal gas equation.

At 27C, 10.0 moles of a gas in a 1.50-L container exert a pressure of 130 atm. Is this an ideal gas?

Discuss the following phenomena in terms of the gas laws: (a) the pressure increase in an automobile tire on a hot day, (b) the popping of a paper bag, (c) the expansion of a weather balloon as it rises in the air, (d) the loud noise heard when a lightbulb shatters

Under the same conditions of temperature and pressure, which of the following gases would behave most ideally: Ne, N2, or CH4? Explain

Nitroglycerin, an explosive compound, decomposes according to the equation 4C3H5(NO3)3(s) 12CO2(g) 1 10H2O(g) 1 6N2(g) 1 O2(g) Calculate the total volume of gases when collected at 1.2 atm and 25C from 2.6 3 102 g of nitroglycerin. What are the partial pressures of the gases under these conditions?

The empirical formula of a compound is CH. At 200C, 0.145 g of this compound occupies 97.2 mL at a pressure of 0.74 atm. What is the molecular formula of the compound?

When ammonium nitrite (NH4NO2) is heated, it decomposes to give nitrogen gas. This property is used to inflate some tennis balls. (a) Write a balanced equation for the reaction. (b) Calculate the quantity (in grams) of NH4NO2 needed to inflate a tennis ball to a volume of 86.2 mL at 1.20 atm and 22C.

The percent by mass of bicarbonate (HCO3 2) in a certain Alka-Seltzer product is 32.5 percent. Calculate the volume of CO2 generated (in mL) at 37C and 1.00 atm when a person ingests a 3.29-g tablet. (Hint: The reaction is between HCO3 2 and HCl acid in the stomach.)

The boiling point of liquid nitrogen is 2196C. On the basis of this information alone, do you think nitrogen is an ideal gas?

In the metallurgical process of refining nickel, the metal is first combined with carbon monoxide to form tetracarbonylnickel, which is a gas at 43C: Ni(s) 1 4CO(g) Ni(CO)4(g) This reaction separates nickel from other solid impurities. (a) Starting with 86.4 g of Ni, calculate the pressure of Ni(CO)4 in a container of volume 4.00 L. (Assume the above reaction goes to completion.) (b) At temperatures above 43C, the pressure of the gas is observed to increase much more rapidly than predicted by the ideal gas equation. Explain.

The partial pressure of carbon dioxide varies with seasons. Would you expect the partial pressure in the Northern Hemisphere to be higher in the summer or winter? Explain

A healthy adult exhales about 5.0 3 102 mL of a gaseous mixture with each breath. Calculate the number of molecules present in this volume at 37C and 1.1 atm. List the major components of this gaseous mixture.

Sodium bicarbonate (NaHCO3) is called baking soda because when heated, it releases carbon dioxide gas, which is responsible for the rising of cookies, doughnuts, and bread. (a) Calculate the volume (in liters) of CO2 produced by heating 5.0 g of NaHCO3 at 180C and 1.3 atm. (b) Ammonium bicarbonate (NH4HCO3) has also been used for the same purpose. Suggest one advantage and one disadvantage of using NH4HCO3 instead of NaHCO3 for baking

A barometer having a cross-sectional area of 1.00 cm2 at sea level measures a pressure of 76.0 cm of mercury. The pressure exerted by this column of mercury is equal to the pressure exerted by all the air on 1 cm2 of Earths surface. Given that the density of mercury is 13.6 g/mL and the average radius of Earth is 6371 km, calculate the total mass of Earths atmosphere in kilograms. (Hint: The surface area of a sphere is 4r 2 where r is the radius of the sphere.)

Some commercial drain cleaners contain a mixture of sodium hydroxide and aluminum powder. When the mixture is poured down a clogged drain, the following reaction occurs: 2NaOH(aq) 1 2Al(s) 1 6H2O(l) 2NaAl(OH)4(aq) 1 3H2(g) The heat generated in this reaction helps melt away obstructions such as grease, and the hydrogen gas released stirs up the solids clogging the drain. Calculate the volume of H2 formed at 23C and 1.00 atm if 3.12 g of Al are treated with an excess of NaOH.

The volume of a sample of pure HCl gas was 189 mL at 25C and 108 mmHg. It was completely dissolved in about 60 mL of water and titrated with an NaOH solution; 15.7 mL of the NaOH solution were required to neutralize the HCl. Calculate the molarity of the NaOH solution

Propane (C3H8) burns in oxygen to produce carbon dioxide gas and water vapor. (a) Write a balanced equation for this reaction. (b) Calculate the number of liters of carbon dioxide measured at STP that could be produced from 7.45 g of propane.

Consider the following apparatus. Calculate the partial pressures of helium and neon after the stopcock is open. The temperature remains constant at 16C. He Ne 1.2 L 0.63 atm 3.4 L 2.8 atm

Nitric oxide (NO) reacts with molecular oxygen as follows: 2NO(g) 1 O2(g) 2NO2(g) Initially NO and O2 are separated as shown here. When the valve is opened, the reaction quickly goes to completion. Determine what gases remain at the end and calculate their partial pressures. Assume that the temperature remains constant at 25C. 4.00 L at 0.500 atm 2.00 L at 1.00 atm NO O2

Consider the apparatus shown here. When a small amount of water is introduced into the flask by squeezing the bulb of the medicine dropper, water is squirted upward out of the long glass tubing. Explain this observation. (Hint: Hydrogen chloride gas is soluble in water.) H2O H2O Rubber bulb HCl gas

Describe how you would measure, by either chemical or physical means, the partial pressures of a mixture of gases of the following composition: (a) CO2 and H2, (b) He and N2.

A certain hydrate has the formula MgSO4 ? xH2O. A quantity of 54.2 g of the compound is heated in an oven to drive off the water. If the steam generated exerts a pressure of 24.8 atm in a 2.00-L container at 120C, calculate x

A mixture of Na2CO3 and MgCO3 of mass 7.63 g is reacted with an excess of hydrochloric acid. The CO2 gas generated occupies a volume of 1.67 L at 1.24 atm and 26C. From these data, calculate the percent composition by mass of Na2CO3 in the mixture

The following apparatus can be used to measure atomic and molecular speed. Suppose that a beam of metal atoms is directed at a rotating cylinder in a vacuum. A small opening in the cylinder allows the atoms to strike a target area. Because the cylinder is rotating, atoms traveling at different speeds will strike the target at different positions. In time, a layer of the metal will deposit on the target area, and the variation in its thickness is found to correspond to Maxwells speed distribution. In one experiment it is found that at 850C some bismuth (Bi) atoms struck the target at a point 2.80 cm from the spot directly opposite the slit. The diameter of the cylinder is 15.0 cm and it is rotating at 130 revolutions per second. (a) Calculate the speed (m/s) at which the target is moving. (Hint: The circumference of a circle is given by 2r, where r is the radius.) (b) Calculate the time (in seconds) it takes for the target to travel 2.80 cm. (c) Determine the speed of the Bi atoms. Compare your result in (c) with the urms of Bi at 850C. Comment on the difference. Rotating cylinder Target Slit Bi atoms

A catalytic converter in an automobile uses a palladium or platinum catalyst (a substance that increases the rate of a reaction without being consumed by the reaction) to convert carbon monoxide gas to carbon dioxide according to the reaction: \(2 \mathrm{CO}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g}) \rightarrow 2 \mathrm{CO}_{2}(\mathrm{g})\) A chemist researching the effectiveness of a new catalyst combines a 2.0:1.0 mole ratio mixture of carbon monoxide and oxygen gas (respectively) over the catalyst in a 2.45 L flask at a total pressure of 745 torr and a temperature of \(552^\circ C\). When the reaction is complete, the pressure in the flask has dropped to 552 torr. What percentage of the carbon monoxide was converted to carbon dioxide?

Commercially, compressed oxygen is sold in metal cylinders. If a 120-L cylinder is filled with oxygen to a pressure of 132 atm at 22C, what is the mass (in grams) of O2 present? How many liters of O2 gas at 1.00 atm and 22C could the cylinder produce? (Assume ideal behavior.)

The shells of hard-boiled eggs sometimes crack due to the rapid thermal expansion of the shells at high temperatures. Suggest another reason why the shells may crack.

Ethylene gas (C2H4) is emitted by fruits and is known to be responsible for their ripening. Based on this information, explain why a bunch of bananas ripens faster in a closed paper bag than in a bowl.

About 8.0 3 106 tons of urea [(NH2)2CO] are used annually as a fertilizer. The urea is prepared at 200C and under high-pressure conditions from carbon dioxide and ammonia (the products are urea and steam). Calculate the volume of ammonia (in liters) measured at 150 atm needed to prepare 1.0 ton of urea.

Some ballpoint pens have a small hole in the main body of the pen. What is the purpose of this hole?

The gas laws are vitally important to scuba divers. The pressure exerted by 33 ft of seawater is equivalent to 1 atm pressure. (a) A diver ascends quickly to the surface of the water from a depth of 36 ft without exhaling gas from his lungs. By what factor will the volume of his lungs increase by the time he reaches the surface? Assume that the temperature is constant. (b) The partial pressure of oxygen in air is about 0.20 atm. (Air is 20 percent oxygen by volume.) In deep-sea diving, the composition of air the diver breathes must be changed to maintain this partial pressure. What must the oxygen content (in percent by volume) be when the total pressure exerted on the diver is 4.0 atm? (At constant temperature and pressure, the volume of a gas is directly proportional to the number of moles of gases.) (Hint: See the Chemistry in Action essay on p. 200.)

Nitrous oxide (N2O) can be obtained by the thermal decomposition of ammonium nitrate (NH4NO3). (a) Write a balanced equation for the reaction. (b) In a certain experiment, a student obtains 0.340 L of the gas at 718 mmHg and 24C. If the gas weighs 0.580 g, calculate the value of the gas constant

Two vessels are labeled A and B. Vessel A contains NH3 gas at 70C, and vessel B contains Ne gas at the same temperature. If the average kinetic energy of NH3 is 7.1 3 10221 J/molecule, calculate the meansquare speed of Ne atoms in m2 /s2 .

Which of the following molecules has the largest a value: CH4, F2, C6H6, Ne?

The following procedure is a simple though somewhat crude way to measure the molar mass of a gas. A liquid of mass 0.0184 g is introduced into a syringe like the one shown here by injection through the rubber tip using a hypodermic needle. The syringe is then transferred to a temperature bath heated to 45C, and the liquid vaporizes. The final volume of the vapor (measured by the outward movement of the plunger) is 5.58 mL and the atmospheric pressure is 760 mmHg. Given that the compounds empirical formula is CH2, determine the molar mass of the compound. 5 4 3 2 1 Rubber tip

In 1995 a man suffocated as he walked by an abandoned mine in England. At that moment there was a sharp drop in atmospheric pressure due to a change in the weather. Suggest what might have caused the mans death.

Acidic oxides such as carbon dioxide react with basic oxides like calcium oxide (CaO) and barium oxide (BaO) to form salts (metal carbonates). (a) Write equations representing these two reactions. (b) A student placed a mixture of BaO and CaO of combined mass 4.88 g in a 1.46-L flask containing carbon dioxide gas at 35C and 746 mmHg. After the reactions were complete, she found that the CO2 pressure had dropped to 252 mmHg. Calculate the percent composition by mass of the mixture. Assume volumes of the solids are negligible.

Identify the Maxwell speed distribution curves shown here with the following gases: Br2, CH4, N2, SO3. 0 500 Number of molecules Molecular speed (m/s) 1000 1500

The running engine of an automobile produces carbon monoxide (CO), a toxic gas, at the rate of about 188 g CO per hour. A car is left idling in a poorly ventilated garage that is 6.0 m long, 4.0 m wide, and 2.2 m high at 20C. (a) Calculate the rate of CO production in moles per minute. (b) How long would it take to build up a lethal concentration of CO of 1000 ppmv (parts per million by volume)?

Interstellar space contains mostly hydrogen atoms at a concentration of about 1 atom/cm3 . (a) Calculate the pressure of the H atoms. (b) Calculate the volume (in liters) that contains 1.0 g of H atoms. The temperature is 3 K.

Atop Mt. Everest, the atmospheric pressure is 210 mmHg and the air density is 0.426 kg/m3 . (a) Calculate the air temperature, given that the molar mass of air is 29.0 g/mol. (b) Assuming no change in air composition, calculate the percent decrease in oxygen gas from sea level to the top of Mt. Everest.

Relative humidity is defined as the ratio (expressed as a percentage) of the partial pressure of water vapor in the air to the equilibrium vapor pressure (see Table 5.3) at a given temperature. On a certain summer day in North Carolina the partial pressure of water vapor in the air is 3.9 3 103 Pa at 30C. Calculate the relative humidity.

Under the same conditions of temperature and pressure, why does one liter of moist air weigh less than one liter of dry air? In weather forecasts, an oncoming low-pressure front usually means imminent rainfall. Explain

Air entering the lungs ends up in tiny sacs called alveoli. It is from the alveoli that oxygen diffuses into the blood. The average radius of the alveoli is 0.0050 cm and the air inside contains 14 percent oxygen. Assuming that the pressure in the alveoli is 1.0 atm and the temperature is 37C, calculate the number of oxygen molecules in one of the alveoli. (Hint: The volume of a sphere of radius r is 4 3r 3 .)

A student breaks a thermometer and spills most of the mercury (Hg) onto the floor of a laboratory that measures 15.2 m long, 6.6 m wide, and 2.4 m high. (a) Calculate the mass of mercury vapor (in grams) in the room at 20C. The vapor pressure of mercury at 20C is 1.7 3 1026 atm. (b) Does the concentration of mercury vapor exceed the air quality regulation of 0.050 mg Hg/m3 of air? (c) One way to treat small quantities of spilled mercury is to spray sulfur powder over the metal. Suggest a physical and a chemical reason for this action.

Consider two bulbs containing argon (left) and oxygen (right) gases. After the stopcock is opened, the pressure of the combined gases is 1.08 atm. Calculate the volume of the right bulb. The temperature is kept at 20C. Assume ideal behavior. n 5 0.227 mol V 5 3.60 L n 5 0.144 mol V 5 ? Ar O2

Nitrogen dioxide (NO2) cannot be obtained in a pure form in the gas phase because it exists as a mixture of NO2 and N2O4. At 25C and 0.98 atm, the density of this gas mixture is 2.7 g/L. What is the partial pressure of each gas?

The Chemistry in Action essay on p. 208 describes the cooling of rubidium vapor to 5.0 3 1028 K. Calculate the root-mean-square speed and average kinetic energy of a Rb atom at this temperature.

Lithium hydride reacts with water as follows: LiH(s) 1 H2O(l) LiOH(aq) 1 H2(g) During World War II, U.S. pilots carried LiH tablets. In the event of a crash landing at sea, the LiH would react with the seawater and fill their life belts and lifeboats with hydrogen gas. How many grams of LiH are needed to fill a 4.1-L life belt at 0.97 atm and 12C?

The atmosphere on Mars is composed mainly of carbon dioxide. The surface temperature is 220 K and the atmospheric pressure is about 6.0 mmHg. Taking these values as Martian STP, calculate the molar volume in liters of an ideal gas on Mars

Venuss atmosphere is composed of 96.5 percent CO2, 3.5 percent N2, and 0.015 percent SO2 by volume. Its standard atmospheric pressure is 9.0 3 106 Pa. Calculate the partial pressures of the gases in pascals.

A student tries to determine the volume of a bulb like the one shown on p. 191. These are her results: Mass of the bulb filled with dry air at 23C and 744 mmHg 5 91.6843 g; mass of evacuated bulb 5 91.4715 g. Assume the composition of air is 78 percent N2, 21 percent O2, and 1 percent argon. What is the volume (in milliliters) of the bulb? (Hint: First calculate the average molar mass of air, as shown in Problem 3.152.)

Apply your knowledge of the kinetic theory of gases to the following situations. (a) Two flasks of volumes V1 and V2 (V2 . V1) contain the same number of helium atoms at the same temperature. (i) Compare the root-mean-square (rms) speeds and average kinetic energies of the helium (He) atoms in the flasks. (ii) Compare the frequency and the force with which the He atoms collide with the walls of their containers. (b) Equal numbers of He atoms are placed in two flasks of the same volume at temperatures T1 and T2 (T2 . T1). (i) Compare the rms speeds of the atoms in the two flasks. (ii) Compare the frequency and the force with which the He atoms collide with the walls of their containers. (c) Equal numbers of He and neon (Ne) atoms are placed in two flasks of the same volume, and the temperature of both gases is 74C. Comment on the validity of the following statements: (i) The rms speed of He is equal to that of Ne. (ii) The average kinetic energies of the two gases are equal. (iii) The rms speed of each He atom is 1.47 3 103 m/s.

It has been said that every breath we take, on average, contains molecules that were once exhaled by Wolfgang Amadeus Mozart (17561791). The following calculations demonstrate the validity of this statement. (a) Calculate the total number of molecules in the atmosphere. (Hint: Use the result in Problem 5.106 and 29.0 g/mol as the molar mass of air.) (b) Assuming the volume of every breath (inhale or exhale) is 500 mL, calculate the number of molecules exhaled in each breath at 37C, which is the body temperature. (c) If Mozarts life span was exactly 35 years, what is the number of molecules he exhaled in that period? (Given that an average person breathes 12 times per minute.) (d) Calculate the fraction of molecules in the atmosphere that was exhaled by Mozart. How many of Mozarts molecules do we breathe in with every inhalation of air? Round off your answer to one significant figure. (e) List three important assumptions in these calculations

At what temperature will He atoms have the same urms value as N2 molecules at 25C?

Estimate the distance (in nanometers) between molecules of water vapor at 100C and 1.0 atm. Assume ideal behavior. Repeat the calculation for liquid water at 100C, given that the density of water is 0.96 g/cm3 at that temperature. Comment on your results. (Assume water molecule to be a sphere with a diameter of 0.3 nm.) (Hint: First calculate the number density of water molecules. Next, convert the number density to linear density, that is, number of molecules in one direction.)

Which of the noble gases would not behave ideally under any circumstance? Why?

A relation known as the barometric formula is useful for estimating the change in atmospheric pressure with altitude. The formula is given by P 5 P0e2gmhyRT , where P and P0 are the pressures at height h and sea level, respectively, g is the acceleration due to gravity (9.8 m/s2 ), m is the average molar mass of air (29.0 g/mol), and R is the gas constant. Calculate the atmospheric pressure in atm at a height of 5.0 km, assuming the temperature is constant at 5C and P0 5 1.0 atm

A 5.72-g sample of graphite was heated with 68.4 g of O2 in a 8.00-L flask. The reaction that took place was C(graphite) 1 O2(g) CO2(g) After the reaction was complete, the temperature in the flask was 182C. What was the total pressure inside the flask?

An equimolar mixture of H2 and D2 effuses through an orifice (small hole) at a certain temperature. Calculate the composition (in mole fractions) of the gases that pass through the orifice. The molar mass of D2 is 2.014 g/mol.

A mixture of calcium carbonate (CaCO3) and magnesium carbonate (MgCO3) of mass 6.26 g reacts completely with hydrochloric acid (HCl) to generate 1.73 L of CO2 at 48C and 1.12 atm. Calculate the mass percentages of CaCO3 and MgCO3 in the mixture

A 6.11-g sample of a Cu-Zn alloy reacts with HCl acid to produce hydrogen gas. If the hydrogen gas has a volume of 1.26 L at 22C and 728 mmHg, what is the percent of Zn in the alloy? (Hint: Cu does not react with HCl.)

A stockroom supervisor measured the contents of a partially filled 25.0-gallon acetone drum on a day when the temperature was 18.0C and atmospheric pressure was 750 mmHg, and found that 15.4 gallons of the solvent remained. After tightly sealing the drum, an assistant dropped the drum while carrying it upstairs to the organic laboratory. The drum was dented and its internal volume was decreased to 20.4 gallons. What is the total pressure inside the drum after the accident? The vapor pressure of acetone at 18.0C is 400 mmHg. (Hint: At the time the drum was sealed, the pressure inside the drum, which is equal to the sum of the pressures of air and acetone, was equal to the atmospheric pressure.)

In 2.00 min, 29.7 mL of He effuse through a small hole. Under the same conditions of pressure and temperature, 10.0 mL of a mixture of CO and CO2 effuse through the hole in the same amount of time. Calculate the percent composition by volume of the mixture.

Referring to Figure 5.22, explain the following: (a) Why do the curves dip below the horizontal line labeled ideal gas at low pressures and then why do they arise above the horizontal line at high pressures? (b) Why do the curves all converge to 1 at very low pressures? (c) Each curve intercepts the horizontal line labeled ideal gas. Does it mean that at that point the gas behaves ideally?

A mixture of methane (CH4) and ethane (C2H6) is stored in a container at 294 mmHg. The gases are burned in air to form CO2 and H2O. If the pressure of CO2 is 356 mmHg measured at the same temperature and volume as the original mixture, calculate the mole fractions of the gases

Use the kinetic theory of gases to explain why hot air rises.

One way to gain a physical understanding of b in the van der Waals equation is to calculate the excluded volume. Assume that the distance of closest approach between two similar atoms is the sum of their radii (2r). (a) Calculate the volume around each atom into which the center of another atom cannot penetrate. (b) From your result in (a), calculate the excluded volume for 1 mole of the atoms, which is the constant b. How does this volume compare with the sum of the volumes of 1 mole of the atoms?

Use the van der Waals constants in Table 5.4 to estimate the radius of argon in picometers. (Hint: See Problem 5.160.)

Identify the gas whose root-mean-square speed is 2.82 times that of hydrogen iodide (HI) at the same temperature

A 5.00-mole sample of NH3 gas is kept in a 1.92-L container at 300 K. If the van der Waals equation is assumed to give the correct answer for the pressure of the gas, calculate the percent error made in using the ideal gas equation to calculate the pressure.

The root-mean-square speed of a certain gaseous oxide is 493 m/s at 20C. What is the molecular formula of the compound?

Referring to Figure 5.17, we see that the maximum of each speed distribution plot is called the most probable speed (ump) because it is the speed possessed by the largest number of molecules. It is given by ump 5 12RTym. (a) Compare ump with urms for nitrogen at 25C. (b) The following diagram shows the Maxwell speed distribution curves for an ideal gas at two different temperatures T1 and T2. Calculate the value of T2. 0 T1 5 300 K T2 5 ? Number of molecules Molecular speed (m/s) 500 1000 1500 2000

A gaseous reaction takes place at constant volume and constant pressure in a cylinder shown here. Which of the following equations best describes the reaction? The initial temperature (T1) is twice that of the final temperature (T2). (a) A 1 B C (b) AB C 1 D (c) A 1 B C 1 D (d) A 1 B 2C 1 D T1 T2

A gaseous hydrocarbon (containing C and H atoms) in a container of volume 20.2 L at 350 K and 6.63 atm reacts with an excess of oxygen to form 205.1 g of CO2 and 168.0 g of H2O. What is the molecular formula of the hydrocarbon?

Three flasks containing gases A (red) and B (green) are shown here. (i) If the pressure in (a) is 4.0 atm, what are the pressures in (b) and (c)? (ii) Calculate the total pressure and partial pressure of each gas after the valves are opened. The volumes of (a) and (c) are 4.0 L each and that of (b) is 2.0 L. The temperature is the same throughout. (a) (b) (c)

(a) Show that the pressure exerted by a fluid P (in pascals) is given by P 5 hdg, where h is the column of the fluid in meters, d is the density in kg/m3 , and g is the acceleration due to gravity (9.81 m/s2 ). (Hint: See Appendix 2.) (b) The volume of an air bubble that starts at the bottom of a lake at 5.24C increases by a factor of 6 as it rises to the surface of water where the temperature is 18.73C and the air pressure is 0.973 atm. The density of the lake water is 1.02 g/cm3 . Use the equation in (a) to determine the depth of the lake in meters.

A student first measured the total pressure of a mixture of gases methane (CH4), ethane (C2H6), and propane (C3H8) at a certain temperature, which turned out to be 4.50 atm. She then recorded the mass spectra of the gases shown here. Calculate the partial pressure of the gases. 0 0 Intensity of peaks (arbitrary units) Molecular mass (amu) 10 20 30 40 50 1 2 3 4 5

In 2012, Felix Baumgartner jumped from a balloon roughly 24 mi above Earth, breaking the record for the highest skydive. He reached speeds of more than 700 miles per hour and became the first skydiver to exceed the speed of sound during free fall. The helium-filled plastic balloon used tocarry Baumgartner to the edge of space was designed to expand to 8.5 3 108L in order to accommodate the low pressures at the altituderequired to break the record. (a) Calculate the mass of helium in the balloon from the conditions at the time of the jump (8.5 3 108 L, 267.8C,0.027 mmHg). (b) Determine the volume of the helium in the balloon just before it was released,assuming a pressure of 1.0 atm and a tempera tureof 23C.

Which of the following has a greater mass: a sample of air of volume V at a certain temperature T and pressure P or a sample of air plus water vapor having the same volume and at the same temperature and pressure?

A flask with a volume of 14.5 L contains 1.25 moles of helium gas. Estimate the average distance between He atoms in nanometers.

Hyperbaric oxygen therapy (HBOT) is very effective in treating burns, crush injuries that impede blood flow, and tissue-damaging infections, as well as carbon monoxide poisoning. However, it has generated some controversy in its application to other maladies (for example, autism, multiple sclerosis). A typical oxygen hyperbaric chamber is shown here. HBOT can be administered using pressure up to six atmospheres, but lower pressures are more common. (a) If this chamber was pressurized to 3.0 atm with pure oxygen, how many moles of O2 would be contained in an empty chamber? (b) Given that a full tank of oxygen contains about 2500 moles of the gas, how many times could the chamber be filled with a single tank of oxygen?

(a) Fluorescent lightbulbs contain a small amount of mercury, giving a mercury vapor pressure of around 1 3 1025 atm. When excited electrically, the Hg atoms emit UV light, which excites the phosphor coating of the inner tube, which then emits visible (white) light. Estimate the mass of Hg vapor present in the type of long, thin fluorescent tubes used in offices. (b) Ordinary tungsten incandescent lightbulbs used in households are filled with argon gas at about 0.5 atm to retard the sublimation of the tungsten filament. Estimate the number of moles of Ar in a typical lightbulb

(a) Estimate the volume of air at 1.0 atm and 22C needed to fill a bicycle tire to a pressure of 5.0 atm at the same temperature. (Note that the 5.0 atm is the gauge pressure, which is the difference between the pressure in the tire and atmospheric pressure.) (b) The tire is pumped by filling the cylinder of a hand pump with air at 1.0 atm and then, by compressing the gas in the cylinder, adding all the air in the pump to the air in the tire. If the volume of the pump is 33 percent of the tires volume, what is the gauge pressure in the tire after three full strokes of the pump?

On October 15, 2009, a homemade helium balloon was released, and for a while authorities were led to believe that a 6-year-old boy had been carried away in the balloon. (The incident was later revealed to be a hoax.) The balloon traveled more than 50 mi and reached a height of 7000 ft. The shape and span of the balloon are shown in the figure. How much weight could this balloon lift? (A helium balloon can lift a mass equal to the difference in the mass of air and the mass of helium that would be contained in the balloon.) Could it actually lift a 6-year-old boy? 20 ft

A gas sample has an initial pressure of 547 mmHg and an initial volume of 0.500 L. What is the pressure (in atm) when the volume of the sample is decreased to 225 mL? (Assume constant temperature and constant number of moles of gas.) a) 1.60 X 10-3 atm b) 1.60 atm c) 0.324 atm d) 1.22 atm

Problem 2SAQ A gas sample has a volume of 178 mL at 0.00 °C. The temperature is raised (at constant pressure) until the volume reaches 211 mL. What is the temperature of the gas sample in °C at this volume? a) 0.00 °C b) 324 °C c) - 43 °C d) 51 °C

Problem 3SAQ What is the pressure of 1.78 g of nitrogen gas confined to a volume of 0.118 L at 25 °C? a) 13.2 atm b) ) 369 atm c) 1.10 atm A d) 26.3 atm

What is the density of a sample of argon gas at 55 °C and 765 mmHg? a) 2.99 g/L b) 1.13 x 103 g/L c) 1.49 g/L d) 8.91 g>L

Problem 5SAQ Which gas sample has the greatest volume at STP? a) 10.0 g Ar b) 10.0 g Kr c) 10.0 g Xe d) None of the above (They all have the same volume.)

Problem 6SAQ A 1.25 g gas sample occupies 663 mL at 25 °C and 1.00 atm. What is the molar mass of the gas? a) 0.258 g/mol b) 0.0461 g/mol c) 3.87 g/mol d) 46.1 g/mol

Problem 7SAQ A 255 mL gas sample contains argon and nitrogen at a temperature of 65 °C. The total pressure of the sample is 725 mmHg and the partial pressure of argon is 231 mmHg. What mass of nitrogen is present in the sample? a) 0.324 g nitrogen b) 0.167 g nitrogen c) 0.0837 g nitrogen d) 0.870 g nitrogen

A gas mixture in a 1.55 L at 298 K container contains 10.0 g of Ne and 10.0 g of Ar. Calculate the partial pressure (in atm) of Ne and Ar in the container. a) PNe = 10.5 atm , PAr = 5.29 atm b) PNe = 5.83 atm , PAr = 2.95 atm c) PNe = 5.88 atm , PAr = 5.88 atm d) PNe = 7.82 atm , PAr = 3.95 atm

Problem 9SAQ A gas sample at STP contains 1.15 g oxygen and 1.55 g nitrogen. What is the volume of the gas sample? a) 1.26 L b) 2.04 L c) 4.08 L d) 61.0 L

Problem 10E Explain why hot air balloons float above the ground and why the second story of a two-story home is often warmer than the ground story.

Aluminum reacts with chlorine gas to form aluminum chloride. What minimum volume of chlorine gas (at 298 K and 225 mmHg) is required to completely react with 7.85 g of aluminum? a) 36.0 L b) 24.0 L c) 0.0474 L d) 16.0 L

Problem 11E What is the ideal gas law? Why is it useful?

Calculate the root mean square velocity of \(I_{2} (g)\) at 373 K. a) 19.0 m/s b) 191 m/s c) 6.05 m/s d) 99.1 m/s

Problem 12SAQ Which gas has the greatest kinetic energy at STP? a) He b) Ne c) Ar d) None of the above (All have the same kinetic energy.)

Problem 22E Describe how the molecules in a perfume bottle travel from the bottle to your nose. What is mean free path?

Problem 28E The world record for lowest pressure (at sea level) was 652.5 mmHg recorded inside Typhoon Tip on October 12, 1979, in the western Pacific Ocean. Convert this pressure to each indicated unit. a . torr b . atm c . in Hg d . psi

Given a barometric pressure of 762.4 mmHg, calculate the pressure of each gas sample as indicated by the manometer.

Given a barometric pressure of 751.5 mmHg, calculate the pressure of each gas sample as indicated by the manometer.

A sample of gas has an initial volume of 5.6 L at a pressure of 735 mmHg. If the volume of the gas is increased to 9.4 L, what is its pressure?

Problem 32E A sample of gas has an initial volume of 13.9 L at a pressure of 1.22 atm. If the sample is compressed to a volume of 10.3 L, what is its pressure?

Problem 33E A 48.3 mL sample of gas in a cylinder is warmed from 22 °C to 87 °C. What is its volume at the final temperature?

Problem 34E A syringe containing 1.55 mL of oxygen gas is cooled from 95.3 °C to 0.0 °C. What is the final volume of oxygen gas?

A balloon contains \(0.158 \mathrm{~mol}\) of gas and has a volume of \(2.46 \mathrm{~L}\). If an additional \(0.113 \mathrm{~mol}\) of gas is added to the balloon (at the same temperature and pressure), what is its final volume?

Problem 36E A cylinder with a moveable piston contains 0.553 mol of gas and has a volume of 253 mL. What is its volume if an additional 0.365 mol of gas is added to the cylinder? (Assume constant temperature and pressure.)

Problem 37E What is the volume occupied by 0.118 mol of helium gas at a pressure of 0.97 atm and a temperature of 305 K? Would the volume be different if the gas was argon (under the same conditions)?

Problem 38E What is the volume occupied by 12.5 g of argon gas at a pressure of 1.05 atm and a temperature of 322 K? Would the volume be different if the sample were 12.5 g of helium (under identical conditions)?

What is the pressure in a 10.0 L cylinder filled with 0.448 mol of nitrogen gas at a temperature of 315 K?

Problem 40E What is the pressure in a 15.0 L cylinder filled with 32.7 g of oxygen gas at a temperature of 302 K?

Problem 41E A cylinder contains 28.5 L of oxygen gas at a pressure of 1.8 atm and a temperature of 298 K. How much gas (in moles) is in the cylinder?

Problem 42E What is the temperature of 0.52 mol of gas at a pressure of 1.3 atm and a volume of 11.8 L?

Problem 43E An automobile tire has a maximum rating of 38.0 psi (gauge pressure). The tire is inflated (while cold) to a volume of 11.8 L and a gauge pressure of 36.0 psi at a temperature of 12.0 °C. Driving on a hot day, the tire warms to 65.0 °C and its volume expands to 12.2 L. Does the pressure in the tire exceed its maximum rating? (Note: The gauge pressure is the differencebetween the total pressure and atmospheric pressure. In this case, assume that atmospheric pressure is 14.7 psi.)

Problem 44E A weather balloon is inflated to a volume of 28.5 L at a pressure of 748 mmHg and a temperature of 28.0 °C. The balloon rises in the atmosphere to an altitude of approximately 25,000 feet, where the pressure is 385 mmHg and the temperature is -15.0 °C. Assuming the balloon can freely expand, calculate the volume of the balloon at this altitude.

A piece of dry ice (solid carbon dioxide) with a mass of \(28.8 \mathrm{~g}\) sublimes (converts from solid to gas) into a large balloon. Assuming that all of the carbon dioxide ends up in the balloon, what is the volume of the balloon at a temperature of \(22^{\circ} \mathrm{C}\) and a pressure of \(742 \mathrm{mmHg}\)?

Problem 46E A 1.0 L container of liquid nitrogen is kept in a closet measuring 1.0 m by 1.0 m by 2.0 m. Assuming that the container is completely full, that the temperature is 25.0 °C, and that the atmospheric pressure is 1.0 atm, calculate the percent (by volume) of air that is displaced if all of the liquid nitrogen evaporates. (Liquid nitrogen has a density of 0.807 g/mL.)

Problem 47E A wine-dispensing system uses argon canisters to pressurize and preserve wine in the bottle. An argon canister for the system has a volume of 55.0 mL and contains 26.0 g of argon. Assuming ideal gas behavior, what is the pressure in the canister at 295 K? When the argon is released from the canister, it expands to fill the wine bottle. How many 750.0 mL wine bottles can be purged with the argon in the canister at a pressure of 1.20 atm and a temperature of 295 K?

Problem 48E Pressurized carbon dioxide inflators can be used to inflate a bicycle tire in the event of a flat. These inflators use metal cartridges that contain 16.0 g of carbon dioxide. At 298 K, to what pressure (in psi) can the carbon dioxide in the cartridge inflate a 3.45 L mountain bike tire? (Note: The gauge pressure is the difference between the total pressure and atmospheric pressure. In this case, assume that atmospheric pressure is 14.7 psi.)

Which gas sample representation has the greatest pressure? Assume that all the samples are at the same temperature. Explain.

This picture represents a sample of gas at a pressure of 1 atm, a volume of 1 L, and a temperature of \(25\ ^{\circ}\mathrm{C}\). Draw a similar picture showing what would happen to the sample if the volume were reduced to 0.5 L and the temperature were increased to \(250\ ^{\circ}\mathrm{C}\). What would happen to the pressure?

Aerosol cans carry clear warnings against incineration because of the high pressures that can develop upon heating. Suppose that a can contains a residual amount of gas at a pressure of 755 mmHg and a temperature of \(25^{\ \circ}\mathrm{C}\). What would the pressure be if the can were heated to \(1155^{\ \circ}\mathrm{C}\)?

Problem 52E A sample of nitrogen gas in a 1.75 L container exerts a pressure of 1.35 atm at 25 °C. What is the pressure if the volume of the container is maintained constant and the temperature is raised to 355 °C?

Problem 53E Use the molar volume of a gas at STP to determine the volume (in L) occupied by 33.6 g of neon at STP.

Problem 54E Use the molar volume of a gas at STP to calculate the density (in g/L) of nitrogen gas at STP.

Problem 55E What is the density (in g/L) of hydrogen gas at 20.0 °C and a pressure of 1655 psi?

Problem 57E A 248 mL gas sample has a mass of 0.433 g at a pressure of 745 mmHg and a temperature of 28 °C. What is the molar mass of the gas?

A sample of N2O gas has a density of 2.85 g/L at 298 K. What is the pressure of the gas (in mmHg)?

Problem 58E A 113 mL gas sample has a mass of 0.171 g at a pressure of 721 mmHg and a temperature of 32 °C. What is the molar mass of the gas?

Problem 59E A sample of gas has a mass of 38.8 mg. Its volume is 224 mL at a temperature of 55 °C and a pressure of 886 torr. Find the molar mass of the gas.

A sample of gas has a mass of 0.555 g. Its volume is 117 mL at a temperature of \(85\ ^{\circ}\mathrm{C}\) and a pressure of 753 mmHg. Find the molar mass of the gas.

A gas mixture contains each of the following gases at the indicated partial pressures: N2, 215 torr; O2, 102 torr; and He, 117 torr. What is the total pressure of the mixture? What mass of each gas is present in a 1.35 L sample of this mixture at 25.0 °C?

A gas mixture with a total pressure of 745 mmHg contains each of the following gases at the indicated partial pressures: CO2, 125 mmHg; Ar, 214 mmHg; and O2, 187 mmHg. The mixture also contains helium gas. What is the partial pressure of the helium gas? What mass of helium gas is present in a 12.0 L sample of this mixture at 273 K?

A \(1.20 \mathrm{~g}\) sample of dry ice is added to a \(755 \mathrm{~mL}\) flask containing nitrogen gas at a temperature of \(25.0{ }^{\circ} \mathrm{C}\) and a pressure of \(725 \mathrm{mmHg}\). The dry ice sublimes (converts from solid to gas) and the mixture returns to \(25.0^{\circ} \mathrm{C}\). What is the total pressure in the flask?

Problem 64E A 275 mL flask contains pure helium at a pressure of 752 torr. A second flask with a volume of 475 mL contains pure argon at a pressure of 722 torr. If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of each gas and the total pressure?

A gas mixture contains 1.25 g N2 and 0.85 g O2 in a 1.55 L container at 18 °C. Calculate the mole fraction and partial pressure of each component in the gas mixture.

What is the mole fraction of oxygen gas in air (see Table 5.3 )? What volume of air contains 10.0 g of oxygen gas at 273 K and 1.00 atm?

Problem 67E The hydrogen gas formed in a chemical reaction is collected over water at 30.0 °C at a total pressure of 732 mmHg. What is the partial pressure of the hydrogen gas collected in this way? If the total volume of gas collected is 722 mL, what mass of hydrogen gas is collected?

The air in a bicycle tire is bubbled through water and collected at \(25 ^\circ C\). If the total volume of gas collected is 5.45 L at a temperature of \(25 ^\circ C\) and a pressure of 745 torr, how many moles of gas were in the bicycle tire?

The zinc within a copper-plated penny will dissolve in hydrochloric acid if the copper coating is filed down in several spots (so that the hydrochloric acid can get to the zinc). The reaction between the acid and the zinc is 2 H+(aq) + Zn(s) ? H2(g) + Zn2+(aq). When the zinc in a certain penny dissolves, the total volume of gas collected over water at 25 °C is 0.951 L at a total pressure of 748 mmHg. What mass of hydrogen gas is collected?

Problem 70E A heliox deep-sea diving mixture contains 2.0 g of oxygen to every 98.0 g of helium. What is the partial pressure of oxygen when this mixture is delivered at a total pressure of 8.5 atm?

Consider the chemical reaction: How many liters of hydrogen gas are formed from the complete reaction of 15.7 g C? Assume that the hydrogen gas is collected at a pressure of 1.0 atm and a temperature of 355 K.

Consider the chemical reaction: What mass of H 2 O is required to form 1.4 L of O2 at a temperature of 315 K and a pressure of 0.957 atm?

\(\mathrm{CH}_{3} \mathrm{OH}\) can be synthesized by the reaction: \(\mathrm{CO}(g)+2 \mathrm{H}_{2}(g) \rightarrow \mathrm{CH}_{3} \mathrm{OH}(g)\) What volume of \(\mathrm{H}_{2}\) gas (in L), at 748 mmHg and \(86^{\circ} \mathrm{C}\), is required to synthesize 25.8 g \(\mathrm{CH}_{3} \mathrm{OH}\)? How many liters of CO gas, measured under the same conditions, are required?

Oxygen gas reacts with powdered aluminum according to the reaction: What volume of O2 gas (in L), measured at 782 mmHg and 25 °C, completely reacts with 53.2 g Al?

Automobile air bags inflate following a serious impact. The impact triggers the chemical reaction: If an automobile air bag has a volume of 11.8 L, what mass of NaN3 (in g) is required to fully inflate the air bag upon impact? Assume STP conditions.

Lithium reacts with nitrogen gas according to the reaction: What mass of lithium (in g) reacts completely with 58.5 mL of N2 gas at STP?

Hydrogen gas (a potential future fuel) can be formed by the reaction of methane with water according to the equation: \(\mathrm{CH}_4(g)+\mathrm{H}_2\mathrm{O}(g)\rightarrow\mathrm{CO}(g)+3\mathrm{\ H}_2(g)\) In a particular reaction, 25.5 L of methane gas (measured at a pressure of 732 torr and a temperature of \(25\ ^{\circ}\mathrm{C}\)) mixes with 22.8 L of water vapor (measured at a pressure of 702 torr and a temperature of \(125\ ^{\circ}\mathrm{C}\)). The reaction produces 26.2 L of hydrogen gas at STP. What is the percent yield of the reaction?

Ozone is depleted in the stratosphere by chlorine from CF3Cl according to this set of equations: What total volume of ozone at a pressure of 25.0 mmHg and a temperature of 225 K is destroyed when all of the chlorine from 15.0 g of CF3Cl goes through ten cycles of the given reactions?

Chlorine gas reacts with fluorine gas to form chlorine trifluoride. A 2.00 L reaction vessel, initially at 298 K, contains chlorine gas at a partial pressure of 337 mmHg and fluorine gas at a partial pressure of 729 mmHg. Identify the limiting reactant and determine the theoretical yield of ClF3 in grams.

Carbon monoxide gas reacts with hydrogen gas to form methanol. \(\mathrm{CO}(g)+2 \mathrm{H}_{2}(g) \ \rightarrow \ \mathrm{CH}_{3} \mathrm{OH}(g)\) A 1.50 L reaction vessel, initially at 305 K, contains carbon monoxide gas at a partial pressure of 232 mmHg and hydrogen gas at a partial pressure of 397 mmHg. Identify the limiting reactant and determine the theoretical yield of methanol in grams.

Problem 81E Consider a 1.0 L sample of helium gas and a 1.0 L sample of argon gas, both at room temperature and atmospheric pressure. a. Do the atoms in the helium sample have the same average kinetic energy as the atoms in the argon sample? b. Do the atoms in the helium sample have the same average velocity as the atoms in the argon sample? c. Do the argon atoms, because they are more massive, exert a greater pressure on the walls of the container? Explain. d. Which gas sample has the faster rate of effusion?

Problem 82E A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and xenon. a. Which of the two gases exerts the greater partial pressure? b. The molecules or atoms of which gas have the greater average velocity? c. The molecules of which gas have the greater average kinetic energy? d. If a small hole were opened in the flask, which gas effuses more quickly?

Calculate the root mean square velocity and kinetic energy of F2, Cl2, and Br2 at 298 K. Rank the three halogens with respect to their rate of effusion.

Calculate the root mean square velocity and kinetic energy of CO, CO2, and SO3 at 298 K. Which gas has the greatest velocity? The greatest kinetic energy? The greatest effusion rate?

We separate uranium-235 from U-238 by fluorinating a sample of uranium to form UF6 (which is a gas) and then taking advantage of the different rates of effusion and diffusion for compounds containing the two isotopes. Calculate the ratio of effusion rates for 238UF6 and 235UF6. The atomic mass of U-235 is 235.054 amu and that of U-238 is 238.051 amu.

Problem 86E Calculate the ratio of effusion rates for Ar and Kr.

Problem 87E A sample of neon effuses from a container in 76 seconds. The same amount of an unknown noble gas requires 155 seconds. Identify the gas.

A sample of N2O effuses from a container in 42 seconds. How long will it take the same amount of gaseous I2 to effuse from the same container under identical conditions?

The graph shows the distribution of molecular velocities for two different molecules (A and B) at the same temperature. Which molecule has the higher molar mass? Which molecule has the higher rate of effusion?

Which postulate of the kinetic molecular theory breaks down under conditions of high pressure? Explain.

The graph shows the distribution of molecular velocities for the same molecule at two different temperatures (T1 and T2). Which temperature is greater? Explain.

Problem 92E Which postulate of the kinetic molecular theory breaks down under conditions of low temperature? Explain.

Problem 93E Use the van der Waals equation and the ideal gas equation to calculate the volume of 1.000 mol of neon at a pressure of 500.0 atm and a temperature of 355.0 K. Explain why the two values are different. (Hint: One way to solve the van der Waals equation for V is to use successive approximations. Use the ideal gas law to get a preliminary estimate for V .)

Use the van der Waals equation and the ideal gas equation to calculate the pressure exerted by 1.000 mol of Cl2 in a volume of 5.000 L at a temperature of 273.0 K. Explain why the two values are different.

Modern pennies are composed of zinc coated with copper. A student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coating (to expose the underlying zinc). The student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the HCl (the copper remains undissolved): The student collects the hydrogen produced over water at 25 °C. The collected gas occupies a volume of 0.899 L at a total pressure of 791 mmHg. Calculate the percent zinc (by mass) in the penny. (Assume that all the Zn in the penny dissolves.)

Problem 96E A 2.85 g sample of an unknown chlorofluorocarbon decomposes and produces 564 mL of chlorine gas at a pressure of 752 mmHg and a temperature of 298 K. What is the percent chlorine (by mass) in the unknown chlorofluorocarbon?

Problem 97E The mass of an evacuated 255 mL flask is 143.187 g. The mass of the flask filled with 267 torr of an unknown gas at 25 °C is 143.289 g. Calculate the molar mass of the unknown gas.

Problem 98E A 118 mL flask is evacuated and found to have a mass of 97.129 g. When the flask is filled with 768 torr of helium gas at 35 °C, it has a mass of 97.171 g. Was the helium gas pure?

Problem 99E A gaseous hydrogen- and carbon-containing compound is decomposed and found to contain 82.66% carbon and 17.34% hydrogen by mass. The mass of 158 mL of the gas, measured at 556 mmHg and 25 °C, was 0.275 g. What is the molecular formula of the compound?

Problem 100E A gaseous hydrogen- and carbon-containing compound is decomposed and found to contain 85.63% C and 14.37% H by mass. The mass of 258 mL of the gas, measured at STP, was 0.646 g. What is the molecular formula of the compound?

Consider the reaction: \(2\mathrm{\ NiO}(s)\rightarrow2\ \mathrm{Ni}(s)+\mathrm{O}_2(g)\) If \(\mathrm{O}_{2}\) is collected over water at \(40.0\ ^{\circ}\mathrm{C}\) and a total pressure of 745 mmHg, what volume of gas is collected for the complete reaction of 24.78 g of NiO?

Problem 103E When hydrochloric acid is poured over potassium sulfide, 42.9 Ml of hydrogen sulfide gas is produced at a pressure of 752 torr and 25.8 °C. Write an equation for the gas-evolution reaction and determine how much potassium sulfide (in grams) reacted.

Consider the reaction: If this reaction produces 15.8 g of Ag( s ), what total volume of gas can be collected over water at a temperature of 25 °C and a total pressure of 752 mmHg?

Consider the reaction: a. If 285.5 mL of SO2 reacts with 158.9 mL of O2 (both measured at 315 K and 50.0 mmHg), what is the limiting reactant and the theoretical yield of SO3a? b. If 187.2 mL of SO3 is collected (measured at 315 K and 50.0 mmHg), what is the percent yield for the reaction?

Ammonium carbonate decomposes upon heating according to the balanced equation: Calculate the total volume of gas produced at 22 °C and 1.02 atm by the complete decomposition of 11.83 g of ammonium carbonate.

Ammonium nitrate decomposes explosively upon heating according to the balanced equation: Calculate the total volume of gas (at 125 °C and 748 mmHg) produced by the complete decomposition of 1.55 kg of ammonium nitrate.

Problem 107E Olympic cyclists fill their tires with helium to make them lighter. Calculate the mass of air in an air-filled tire and the mass of helium in a helium-filled tire. What is the mass difference between the two? Assume that the volume of the tire is 855 mL, that it is filled to a total pressure of 125 psi, and that the temperature is 25 °C. Also, assume an average molar mass for air of 28.8 g/mol.

In a common classroom demonstration, a balloon is filled with air and submerged in liquid nitrogen. The balloon contracts as the gases within the balloon cool. Suppose a balloon initially contains 2.95 L of air at a temperature of 25.0 °C and a pressure of 0.998 atm. Calculate the expected volume of the balloon upon cooling to -196 °C (the boiling point of liquid nitrogen). When the demonstration is carried out, the actual volume of the balloon decreases to 0.61 L. How does the observed volume of the balloon compare to your calculated value? Explain the difference.

Gaseous ammonia is injected into the exhaust stream of a coal burning power plant to reduce the pollutant NO to N2 according to the reaction: Suppose that the exhaust stream of a power plant has a flow rate of 335 L/s at a temperature of 955 K, and that the exhaust contains a partial pressure of NO of 22.4 torr. What should be the flow rate of ammonia delivered at 755 torr and 298 K into the stream to react completely with the NO if the ammonia is 65.2% pure (by volume)?

!The emission of NO2 by fossil fuel combustion can be prevented by injecting gaseous urea into the combustion mixture. The urea reduces NO (which oxidizes in air to form NO 2 ) according to the reaction: Suppose that the exhaust stream of an automobile has a flow rate of 2.55 L/s at 655 K and contains a partial pressure of NO of 12.4 torr. What total mass of urea is necessary to react completely with the NO formed during 8.0 hours of driving?

Problem 111E An ordinary gasoline can measuring 30.0 cm by 20.0 cm by 15.0 cm is evacuated with a vacuum pump. Assuming that virtually all of the air can be removed from inside the can, and that atmospheric pressure is 14.7 psi, what is the total force (in pounds) on the surface of the can? Do you think that the can could withstand the force?

Problem 112E Twenty-five milliliters of liquid nitrogen (density = 0.807 g/mL) is poured into a cylindrical container with a radius of 10.0 cm and a length of 20.0 cm. The container initially contains only air at a pressure of 760.0 mmHg (atmospheric pressure) and a temperature of 298 K. If the liquid nitrogen completely vaporizes, what is the total force (in lb) on the interior of the container at 298 K?

A 160.0 L helium tank contains pure helium at a pressure of 1855 psi and a temperature of 298 K. How many 3.5 L helium balloons will the helium in the tank fill? (Assume an atmospheric pressure of 1.0 atm and a temperature of 298 K.)

Problem 114E An 11.5 mL sample of liquid butane (density = 0.573 g/mL)is evaporated in an otherwise empty container at a temperature of 28.5 °C. The pressure in the container following evaporation is 892 torr. What is the volume of the container?

Problem 115E A scuba diver creates a spherical bubble with a radius of 2.5 cm at a depth of 30.0 m where the total pressure (including atmospheric pressure) is 4.00 atm. What is the radius of the bubble when it reaches the surface of the water? (Assume that the atmospheric pressure is 1.00 atm and the temperature is 298 K.)

A catalytic converter in an automobile uses a palladium or platinum catalyst (a substance that increases the rate of a reaction without being consumed by the reaction) to convert carbon monoxide gas to carbon dioxide according to the reaction: A chemist researching the effectiveness of a new catalyst combines a 2.0:1.0 mole ratio mixture of carbon monoxide and oxygen gas (respectively) over the catalyst in a 2.45 L flask at a total pressure of 745 torr and a temperature of 552 °C. When the reaction is complete, the pressure in the flask has dropped to 552 torr. What percentage of the carbon monoxide was converted to carbon dioxide?

A particular balloon can be stretched to a maximum surface area of \(1257 \mathrm{\ cm}^{2}\). The balloon is filled with 3.0 L of helium gas at a pressure of 755 torr and a temperature of 298 K. The balloon is then allowed to rise in the atmosphere. If the atmospheric temperature is 273 K, at what pressure will the balloon burst? (Assume the balloon to be in the shape of a sphere.)

A quantity of \(N_2\) occupies a volume of 1.0 L at 300 K and 1.0 atm. The gas expands to a volume of 3.0 L as the result of a change in both temperature and pressure. Find the density of the gas at these new conditions.

A mixture of CO( g ) and O2( g ) in a 1.0 L container at 1.0 x 103 K has a total pressure of 2.2 atm. After some time the total pressure falls to 1.9 atm as the result of the formation of CO2. Determine the mass (in grams) of CO2 that forms.

The radius of a xenon atom is 1.3 x 10-8 cm . A 100 mL flask is filled with Xe at a pressure of 1.0 atm and a temperature of 273 K. Calculate the fraction of the volume that is occupied by Xe atoms. (Hint: The atoms are spheres.)

Problem 121E A natural gas storage tank is a cylinder with a moveable top whose volume can change only as its height changes. Its radius remains fixed. The height of the cylinder is 22.6 m on a day when the temperature is 22 °C. The next day the height of the cylinder increases to 23.8 m when the gas expands because of a heat wave. Find the temperature on the second day, assuming that the pressure and amount of gas in the storage tank have not changed.

A mixture of 8.0 g CH4 and 8.0 g Xe is placed in a container and the total pressure is found to be 0.44 atm. Determine the partial pressure of CH4.

Problem 123E A steel container of volume 0.35 L can withstand pressures up to 88 atm before exploding. What mass of helium can be stored in this container at 299 K?

Binary compounds of alkali metals and hydrogen react with water to liberate H2(g) . The H2 from the reaction of a sample of NaH with an excess of water fills a volume of 0.490 L above the water. The temperature of the gas is 35 °C and the total pressure is 758 mmHg. Determine the mass of H2 liberated and the mass of NaH that reacted.

Problem 125E In a given diffusion apparatus, 15.0 mL of HBr gas diffused in 1.0 min. In the same apparatus and under the same conditions, 20.3 mL of an unknown gas diffused in 1.0 min. The unknown gas is a hydrocarbon. Find its molecular formula.

A sample of N2O3(g) has a pressure of 0.017 atm. The temperature (in K) is then doubled and the N2O3 undergoes complete decomposition to NO2(g) and NO(g) . Find the total pressure of the mixture of gases assuming constant volume and no additional temperature change.

When 0.583 g of neon is added to an 800 cm3 bulb containing a sample of argon, the total pressure of the gases is 1.17 atm at a temperature of 295 K. Find the mass of the argon in the bulb.

A gas mixture composed of helium and argon has a density of 0.670 g/L at a 755 mmHg and 298 K. What is the composition of the mixture by volume?

A gas mixture contains 75.2% nitrogen and 24.8% krypton by mass. What is the partial pressure of krypton in the mixture if the total pressure is 745 mmHg?

A 10-liter container is filled with 0.10 mol of H2(g) and heated to 3000 K, causing some of the H2(g) to decompose into H( g ). The pressure is found to be 3.0 atm. Find the partial pressure of the H( g ) that forms from H2 at this temperature. ( Assume two significant figures for the temperature.)

A mixture of \(\mathrm{NH}_{3}(g)\) and \(\mathrm{N}_{2} \mathrm{H}_{4}(g)\) is placed in a sealed container at 300 K. The total pressure is 0.50 atm. The container is heated to 1200 K at which time both substances decompose completely according to the equations \(2\ \mathrm{NH}_3(g)\rightarrow\mathrm{N}_2(g)+3\mathrm{\ H}_2(g);\ \mathrm{N}_2\mathrm{H}_4(g)\rightarrow\mathrm{N}_2(g)+2\mathrm{\ H}_2(g)\). After decomposition is complete the total pressure at 1200 K is found to be 4.5 atm. Find the percent of \(\mathrm{N}_{2} \mathrm{H}_{4}(g)\) in the original mixture. (Assume two significant figures for the temperature.)

Problem 132E A quantity of CO gas occupies a volume of 0.48 L at 1.0 atm and 275 K. The pressure of the gas is lowered and its temperature is raised until its volume is 1.3 L. Determine the density of the CO under the new conditions.

When CO2(g) is put in a sealed container at 701 K and a pressure of 10.0 atm and is heated to 1401 K, the pressure rises to 22.5 atm. Some of the CO2 decomposes to CO and O2. Calculate the mole percent of CO2 that decomposes.

The world burns approximately 3.5 x 1012 kg of fossil fuel per year. Use the combustion of octane as the representative reaction and determine the mass of carbon dioxide (the most significant greenhouse gas) formed per year. The current concentration of carbon dioxide in the atmosphere is approximately 387 ppm (by volume). By what percentage does the concentration increase each year due to fossil fuel combustion? Approximate the average properties of the entire atmosphere by assuming that the atmosphere extends from sea level to 15 km and that it has an average pressure of 381 torr and average temperature of 275 K. Assume Earth is a perfect sphere with a radius of 6371 km.

The atmosphere slowly oxidizes hydrocarbons in a number of steps that eventually convert the hydrocarbon into carbon dioxide and water. The overall reaction of a number of such steps for methane gas is Suppose that an atmospheric chemist combines 155 mL of methane at STP, 885 mL of oxygen at STP, and 55.5 mL of NO at STP in a 2.0 L flask. The flask is allowed to stand for several weeks at 275 K. If the reaction reaches 90.0% of completion (90.0% of the limiting reactant is consumed), what is the partial pressure of each of the reactants and products in the flask at 275 K? What is the total pressure in the flask?

Problem 136E Two identical balloons are filled to the same volume, one with air and one with helium. The next day, the volume of the air-filled balloon has decreased by 5.0%. By what percent has the volume of the helium-filled balloon decreased? (Assume that the air is four-fifths nitrogen and one-fifth oxygen and that the temperature did not change.)

A mixture of CH4(g) and C2H6(g) has a total pressure of 0.53 atm. Just enough O2(g) is added to the mixture to bring about its complete combustion to CO2(g) and H2O(g) . The total pressure of the two product gases is found to be 2.2 atm. Assuming constant volume and temperature, find the mole fraction of CH4 in the mixture.

A sample of \(\mathrm{C}_{2} \mathrm{H}_{2}(\mathrm{g})\) has a pressure of 7.8 kPa. After some time a portion of it reacts to form \(\mathrm{C}_{6} \mathrm{H}_{6}(\mathrm{g})\). The total pressure of the mixture of gases is then 3.9 kPa. Assume the volume and the temperature do not change. What fraction of \(\mathrm{C}_{2} \mathrm{H}_{2}(\mathrm{g})\) has undergone reaction?

Problem 139E When the driver of an automobile applies the brakes, the passengers are pushed toward the front of the car, but a helium balloon is pushed toward the back of the car. Upon forward acceleration, the passengers are pushed toward the back of the car, but the helium balloon is pushed toward the front of the car. Why?

The reaction occurs in a closed container: A reaction mixture initially contains 1.5 L of A and 2.0 L of B. Assuming that the volume and temperature of the reaction mixture remain constant, what is the percent change in pressure if the reaction goes to completion?

Problem 140E Suppose that a liquid is ten times denser than water. If you were to sip this liquid at sea level using a straw, what is the maximum length your straw can be?

Problem 142E One mole of nitrogen and one mole of neon are combined in a closed container at STP. How big is the container?

Problem 143E Exactly equal amounts (in moles) of gas A and gas B are combined in a 1 L container at room temperature. Gas B has a molar mass that is twice that of gas A. Which statement is true for the mixture of gases and why? a. The molecules of gas B have greater kinetic energy than those of gas A. b. Gas B has a greater partial pressure than gas A. c. The molecules of gas B have a greater average velocity than those of gas A. d. Gas B makes a greater contribution to the average density of the mixture than gas A.

Which gas would you expect to deviate most from ideal behavior under conditions of low temperature: F2, Cl2, or Br2? Explain.

Problem 145E The volume of a sample of a fixed amount of gas is decreased from 2.0 L to 1.0 L. The temperature of the gas in kelvins is then doubled. What is the final pressure of the gas in terms of the initial pressure?

Problem 146E Which gas sample has the greatest volume at STP? a. 10.0 g Kr b. 10.0 g Xe c. 10.0 g He

Problem 147E Draw a depiction of a gas sample, as described by kinetic molecular theory, containing equal molar amounts of helium, neon, and krypton. Use different color dots to represent each element. Give each atom a “tail” to represent its velocity relative to the others in the mixture.

Francine Prose states, Traditionally, the love of reading has been born and nurtured in high school En glish class (para. 1). Do you think this is generally the case? Describe your experience on this subject.

What does Prose mean when she writes, [B]y concentrating on the students own history they [teachers] narrow the world of experience down to the personal and deny students other sorts of experience the experience of whats in the book, for starters (para. 40)? Do you agree with Proses statement? Why or why not?

What is Prose implying in the following statement about what she calls the new-model En glish-class graduate: But of course whats happening is more complex and subtle than that [seeing books as unconnected to advertising], more

Whom does Prose blame for this state of affairs? Does assigning blame affect the cogency of her argument?

This essay was written in 1999. Do you think Prose would or could make the same argument today? Why or why not?

According to Prose, To hold up [I Know Why the Caged Bird Sings] as a paradigm of memoir, of thought of literature is akin to inviting doctors convicted of malpractice to instruct our medical students (para. 13). Do you agree with this analogy? Explain your answer. What other examples of figurative language can you find in this essay?

Toward the end of the essay (paras. 35, 39, and 43), Prose uses a series of rhetorical questions. What is her purpose in piling one rhetorical question on top of another?

Would Prose have strengthened her argument by including interviews with a few high school students or teachers? Why or why not?

According to Prose, why are American high school students learning to loathe literature? Try to find at least four or five reasons.

Does she propose a solution or recommendations to change this situation? If she does not offer a solution, is her argument weakened? Explain your answer.

How would you describe Emersons tone in this essay?

How would you describe Baldwins overall tone? Cite specific passages to support your description.

Throughout this speech, Wallace builds a tension between two ways of being/ living in the world. What are they? How does he explain and illustrate each to build his argument for the superiority of one over the other?

According to one researcher, a commencement speech has four major characteristics: it acknowledges the graduates, creates an identification between the graduates and the speaker, presents the world and its challenges, and instills hope. To what extent does this speech embody these characteristics? Cite specific passages to support and illustrate your response

If someone asked you what this speech is about, how would you answer in under ten words? Explain your response.

Why do deep-sea divers breathe a mixture of helium and oxygen?

When a gas is collected over water, is the gas pure? Why or why not? How can the partial pressure of the collected gas be determined?

If a reaction occurs in the gas phase at STP, the mass of a product can be determined from the volumes of reactants. Explain.

What are the basic postulates of kinetic molecular theory? How does the concept of pressure follow from kinetic molecular theory?

Explain how Boyles law, Charless law, Avogadros law, and Daltons law all follow from kinetic molecular theory

How is the kinetic energy of a gas related to temperature? How is the root mean square velocity of a gas related to its molar mass?

Describe how the molecules in a perfume bottle travel from the bottle to your nose. What is mean free path?

Explain the difference between diffusion and effusion. How is the effusion rate of a gas related to its molar mass?

Deviations from the ideal gas law are often observed at high pressure and low temperature. Explain this in light of kinetic molecular theory.

The pressure in Denver, Colorado (elevation 5280 ft), averages about 24.9 in Hg. Convert this pressure to each indicated unit. a. atm b. mmHg c. psi d. Pa

The pressure on top of Mt. Everest averages about 235 mmHg. Convert this pressure to each indicated unit. a. torr b. psi c. in Hg d. atm

The North American record for highest recorded barometric pressure is 31.85 in Hg, set in 1989 in Northway, Alaska. Convert this pressure to each indicated unit. a. mmHg b. atm c. torr d. kPa (kilopascals)

The world record for lowest pressure (at sea level) was 652.5 mmHg recorded inside Typhoon Tip on October 12, 1979, in the western Pacific Ocean. Convert this pressure to each indicated unit. a. torr b. atm c. in Hg d. psi

Given a barometric pressure of 762.4 mmHg, calculate the pressure of each gas sample as indicated by the manometer.

Given a barometric pressure of 751.5 mmHg, calculate the pressure of each gas sample as indicated by the manometer.

A sample of gas has an initial volume of 5.6 L at a pressure of 735 mmHg. If the volume of the gas is increased to 9.4 L, what is its pressure?

A sample of gas has an initial volume of 13.9 L at a pressure of 1.22 atm. If the sample is compressed to a volume of 10.3 L, what is its pressure?

A 48.3 mL sample of gas in a cylinder is warmed from 22 C to 87 C. What is its volume at the final temperature?

A syringe containing 1.55 mL of oxygen gas is cooled from 95.3 C to 0.0 C. What is the final volume of oxygen gas?

A balloon contains 0.158 mol of gas and has a volume of 2.46 L. If an additional 0.113 mol of gas is added to the balloon (at the same temperature and pressure), what is its final volume?

A cylinder with a moveable piston contains 0.553 mol of gas and has a volume of 253 mL. What is its volume if an additional 0.365 mol of gas is added to the cylinder? (Assume constant temperature and pressure.)

What is the volume occupied by 0.118 mol of helium gas at a pressure of 0.97 atm and a temperature of 305 K? Would the volume be different if the gas was argon (under the same conditions)?

What is the volume occupied by 12.5 g of argon gas at a pressure of 1.05 atm and a temperature of 322 K? Would the volume be different if the sample were 12.5 g of helium (under identical conditions)?

What is the pressure in a 10.0 L cylinder filled with 0.448 mol of nitrogen gas at a temperature of 315 K?

What is the pressure in a 15.0 L cylinder filled with 32.7 g of oxygen gas at a temperature of 302 K?

A cylinder contains 28.5 L of oxygen gas at a pressure of 1.8 atm and a temperature of 298 K. How much gas (in moles) is in the cylinder?

What is the temperature of 0.52 mol of gas at a pressure of 1.3 atm and a volume of 11.8 L?

An automobile tire has a maximum rating of 38.0 psi (gauge pressure). The tire is inflated (while cold) to a volume of 11.8 L and a gauge pressure of 36.0 psi at a temperature of 12.0 C. Driving on a hot day, the tire warms to 65.0 C and its volume expands to 12.2 L. Does the pressure in the tire exceed its maximum rating? (Note: The gauge pressure is the difference between the total pressure and atmospheric pressure. In this case, assume that atmospheric pressure is 14.7 psi.)

A weather balloon is inflated to a volume of 28.5 L at a pressure of 748 mmHg and a temperature of \(28.0 \ ^\circ C\). The balloon rises in the atmosphere to an altitude of approximately 25,000 feet, where the pressure is 385 mmHg and the temperature is \(-15.0 \ ^\circ C\). Assuming the balloon can freely expand, calculate the volume of the balloon at this altitude.

A piece of dry ice (solid carbon dioxide) with a mass of 28.8 g sublimes (converts from solid to gas) into a large balloon. Assuming that all of the carbon dioxide ends up in the balloon, what is the volume of the balloon at a temperature of 22 C and a pressure of 742 mmHg?

A 1.0 L container of liquid nitrogen is kept in a closet measuring 1.0 m by 1.0 m by 2.0 m. Assuming that the container is completely full, that the temperature is 25.0 C, and that the atmospheric pressure is 1.0 atm, calculate the percent (by volume) of air that is displaced if all of the liquid nitrogen evaporates. (Liquid nitrogen has a density of 0.807 g/mL.)

A wine-dispensing system uses argon canisters to pressurize and preserve wine in the bottle. An argon canister for the system has a volume of 55.0 mL and contains 26.0 g of argon. Assuming ideal gas behavior, what is the pressure in the canister at 295 K? When the argon is released from the canister, it expands to fill the wine bottle. How many 750.0 mL wine bottles can be purged with the argon in the canister at a pressure of 1.20 atm and a temperature of 295 K?

Pressurized carbon dioxide inflators can be used to inflate a bicycle tire in the event of a flat. These inflators use metal cartridges that contain 16.0 g of carbon dioxide. At 298 K, to what pressure (in psi) can the carbon dioxide in the cartridge inflate a 3.45 L mountain bike tire? (Note: The gauge pressure is the difference between the total pressure and atmospheric pressure. In this case, assume that atmospheric pressure is 14.7 psi.)

Which gas sample representation has the greatest pressure? Assume that all the samples are at the same temperature. Explain.

This picture represents a sample of gas at a pressure of 1 atm, a volume of 1 L, and a temperature of 25 C. Draw a similar picture showing what would happen to the sample if the volume were reduced to 0.5 L and the temperature were increased to 250 C. What would happen to the pressure?

Aerosol cans carry clear warnings against incineration because of the high pressures that can develop upon heating. Suppose that a can contains a residual amount of gas at a pressure of 755 mmHg and a temperature of 25 C. What would the pressure be if the can were heated to 1155 C?

A sample of nitrogen gas in a 1.75 L container exerts a pressure of 1.35 atm at 25 C. What is the pressure if the volume of the container is maintained constant and the temperature is raised to 355 C?

Use the molar volume of a gas at STP to determine the volume (in L) occupied by 33.6 g of neon at STP.

Use the molar volume of a gas at STP to calculate the density (in \(\mathrm{g} / \mathrm{L}\) ) of nitrogen gas at STP.

What is the density (in g/L) of hydrogen gas at 20.0 C and a pressure of 1655 psi?

A sample of \(N_2 O\) gas has a density of 2.85 g/L at 298 K. What is the pressure of the gas (in mmHg)?

A 248 mL gas sample has a mass of 0.433 g at a pressure of 745 mmHg and a temperature of 28 C. What is the molar mass of the gas?

A 113 mL gas sample has a mass of 0.171 g at a pressure of 721 mmHg and a temperature of \(32 \ ^\circ C\). What is the molar mass of the gas?

. A sample of gas has a mass of 38.8 mg. Its volume is 224 mL at a temperature of 55 C and a pressure of 886 torr. Find the molar mass of the gas

A sample of gas has a mass of 0.555 g. Its volume is 117 mL at a temperature of 85 C and a pressure of 753 mmHg. Find the molar mass of the gas.

A gas mixture contains each of the following gases at the indicated partial pressures: N 2 , 215 torr; O 2 , 102 torr; and He, 117 torr. What is the total pressure of the mixture? What mass of each gas is present in a 1.35 L sample of this mixture at 25.0 C?

A gas mixture with a total pressure of 745 mmHg contains each of the following gases at the indicated partial pressures: CO 2 , 125 mmHg; Ar, 214 mmHg; and O 2 , 187 mmHg. The mixture also contains helium gas. What is the partial pressure of the helium gas? What mass of helium gas is present in a 12.0 L sample of this mixture at 273 K?

A 1.20 g sample of dry ice is added to a 755 mL flask containing nitrogen gas at a temperature of 25.0 C and a pressure of 725 mmHg. The dry ice sublimes (converts from solid to gas) and the mixture returns to 25.0 C. What is the total pressure in the flask?

A 275 mL flask contains pure helium at a pressure of 752 torr. A second flask with a volume of 475 mL contains pure argon at a pressure of 722 torr. If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of each gas and the total pressure?

A gas mixture contains 1.25 g N2 and 0.85 g O2 in a 1.55 L container at 18 C. Calculate the mole fraction and partial pressure of each component in the gas mixture.

What is the mole fraction of oxygen gas in air (see Table 5.3 )? What volume of air contains 10.0 g of oxygen gas at 273 K and 1.00 atm?

The hydrogen gas formed in a chemical reaction is collected over water at 30.0 C at a total pressure of 732 mmHg. What is the partial pressure of the hydrogen gas collected in this way? If the total volume of gas collected is 722 mL, what mass of hydrogen gas is collected?

The air in a bicycle tire is bubbled through water and collected at 25 C. If the total volume of gas collected is 5.45 L at a temperature of 25 C and a pressure of 745 torr, how many moles of gas were in the bicycle tire?

The zinc within a copper-plated penny will dissolve in hydrochloric acid if the copper coating is filed down in several spots (so that the hydrochloric acid can get to the zinc). The reaction between the acid and the zinc is 2 H+1aq2 + Zn1s2 S H21g2 + Zn2+1aq2. When the zinc in a certain penny dissolves, the total volume of gas collected over water at 25 C is 0.951 L at a total pressure of 748 mmHg. What mass of hydrogen gas is collected?

A heliox deep-sea diving mixture contains 2.0 g of oxygen to every 98.0 g of helium. What is the partial pressure of oxygen when this mixture is delivered at a total pressure of 8.5 atm?

Consider the chemical reaction: C(s) + H2O(g) S CO(g) + H2(g) How many liters of hydrogen gas are formed from the complete reaction of 15.7 g C? Assume that the hydrogen gas is collected at a pressure of 1.0 atm and a temperature of 355 K.

Consider the chemical reaction: 2 H2O(l) S 2 H2(g) + O2(g) What mass of H 2 O is required to form 1.4 L of O 2 at a temperature of 315 K and a pressure of 0.957 atm?

CH 3 OH can be synthesized by the reaction: CO(g) + 2 H2(g) S CH3OH(g) What volume of H2 gas (in L), at 748 mmHg and 86 C, is required to synthesize 25.8 g CH3OH ? How many liters of CO gas, measured under the same conditions, are required?

Oxygen gas reacts with powdered aluminum according to the reaction: \(4\mathrm{\ Al}(s)+3\ \mathrm{O}_2(g)\rightarrow2\mathrm{\ Al}_2\mathrm{O}_3(s)\) What volume of \(\mathrm{O}_2\) gas (in L), measured at 782 mmHg and \(25\ ^{\circ}\mathrm{C}\), completely reacts with 53.2 g Al?

Automobile air bags inflate following a serious impact. The impact triggers the chemical reaction: 2 NaN3(s) S 2 Na(s) + 3 N2(g) If an automobile air bag has a volume of 11.8 L, what mass of NaN3 (in g) is required to fully inflate the air bag upon impact? Assume STP conditions.

Lithium reacts with nitrogen gas according to the reaction: 6 Li(s) + N2(g) S 2 Li3N(s) What mass of lithium (in g) reacts completely with 58.5 mL of N 2 gas at STP?

Hydrogen gas (a potential future fuel) can be formed by the reaction of methane with water according to the equation: CH4(g) + H2O(g) S CO(g) + 3 H2(g) In a particular reaction, 25.5 L of methane gas (measured at a pressure of 732 torr and a temperature of 25 C) mixes with 22.8 L of water vapor (measured at a pressure of 702 torr and a temperature of 125 C). The reaction produces 26.2 L of hydrogen gas at STP. What is the percent yield of the reaction?

Ozone is depleted in the stratosphere by chlorine from CF3Cl according to this set of equations: CF3Cl + UV light S CF3 + Cl Cl + O3 S ClO + O2 O3 + UV light S O2 + O ClO + O S Cl + O2 What total volume of ozone at a pressure of 25.0 mmHg and a temperature of 225 K is destroyed when all of the chlorine from 15.0 g of CF3Cl goes through ten cycles of the given reactions?

Chlorine gas reacts with fluorine gas to form chlorine trifluoride. \(\mathrm{Cl}_2(\mathrm{g})+3\mathrm{\ F}_2(\mathrm{g})\rightarrow2\ \mathrm{ClF}_3(\mathrm{g})\) A 2.00 L reaction vessel, initially at 298 K, contains chlorine gas at a partial pressure of 337 mmHg and fluorine gas at a partial pressure of 729 mmHg. Identify the limiting reactant and determine the theoretical yield of \(\mathrm{ClF}_{3}\) in grams.

Carbon monoxide gas reacts with hydrogen gas to form methanol. CO(g) + 2 H2(g) S CH3OH(g) A 1.50 L reaction vessel, initially at 305 K, contains carbon monoxide gas at a partial pressure of 232 mmHg and hydrogen gas at a partial pressure of 397 mmHg. Identify the limiting reactant and determine the theoretical yield of methanol in grams.

Consider a 1.0 L sample of helium gas and a 1.0 L sample of argon gas, both at room temperature and atmospheric pressure. a. Do the atoms in the helium sample have the same average kinetic energy as the atoms in the argon sample? b. Do the atoms in the helium sample have the same average velocity as the atoms in the argon sample? c. Do the argon atoms, because they are more massive, exert a greater pressure on the walls of the container? Explain. d. Which gas sample has the faster rate of effusion?

A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and xenon. a. Which of the two gases exerts the greater partial pressure? b. The molecules or atoms of which gas have the greater average velocity? c. The molecules of which gas have the greater average kinetic energy? d. If a small hole were opened in the flask, which gas effuses more quickly?

Calculate the root mean square velocity and kinetic energy of F 2 , Cl 2 , and Br 2 at 298 K. Rank the three halogens with respect to their rate of effusion.

Calculate the root mean square velocity and kinetic energy of CO, CO 2 , and SO 3 at 298 K. Which gas has the greatest velocity? The greatest kinetic energy? The greatest effusion rate?

We separate uranium-235 from U-238 by fluorinating a sample of uranium to form \(\mathrm{UF}_{6}\) (which is a gas) and then taking advantage of the different rates of effusion and diffusion for compounds containing the two isotopes. Calculate the ratio of effusion rates for \({ }^{238} \mathrm{UF}_{6}\) and \({ }^{235} \mathrm{UF}_{6}\). The atomic mass of U-235 is 235.054 amu and that of U-238 is 238.051 amu.

Calculate the ratio of effusion rates for Ar and Kr.

A sample of neon effuses from a container in 76 seconds. The same amount of an unknown noble gas requires 155 seconds. Identify the gas.

A sample of N 2 O effuses from a container in 42 seconds. How long will it take the same amount of gaseous I 2 to effuse from the same container under identical conditions?

The graph shows the distribution of molecular velocities for two different molecules (A and B) at the same temperature. Which molecule has the higher molar mass? Which molecule has the higher rate of effusion?

The graph shows the distribution of molecular velocities for the same molecule at two different temperatures (T1 and T2 ). Which temperature is greater? Explain.

Which postulate of the kinetic molecular theory breaks down under conditions of high pressure? Explain.

Which postulate of the kinetic molecular theory breaks down under conditions of low temperature? Explain.

Use the van der Waals equation and the ideal gas equation to calculate the volume of 1.000 mol of neon at a pressure of 500.0 atm and a temperature of 355.0 K. Explain why the two values are different. (Hint: One way to solve the van der Waals equation for V is to use successive approximations. Use the ideal gas law to get a preliminary estimate for V .)

Use the van der Waals equation and the ideal gas equation to calculate the pressure exerted by 1.000 mol of Cl 2 in a volume of 5.000 L at a temperature of 273.0 K. Explain why the two values are different.

Modern pennies are composed of zinc coated with copper. A student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coating (to expose the underlying zinc). The student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the HCl (the copper remains undissolved): Zn(s) + 2 HCl(aq) S H2(g) + ZnCl2(aq) The student collects the hydrogen produced over water at 25 C. The collected gas occupies a volume of 0.899 L at a total pressure of 791 mmHg. Calculate the percent zinc (by mass) in the penny. (Assume that all the Zn in the penny dissolves.)

A 2.85 g sample of an unknown chlorofluorocarbon decomposes and produces 564 mL of chlorine gas at a pressure of 752 mmHg and a temperature of 298 K. What is the percent chlorine (by mass) in the unknown chlorofluorocarbon?

The mass of an evacuated 255 mL flask is 143.187 g. The mass of the flask filled with 267 torr of an unknown gas at 25 C is 143.289 g. Calculate the molar mass of the unknown gas.

A 118 mL flask is evacuated and found to have a mass of 97.129 g. When the flask is filled with 768 torr of helium gas at 35 C, it has a mass of 97.171 g. Was the helium gas pure?

A gaseous hydrogen- and carbon-containing compound is decomposed and found to contain 82.66% carbon and 17.34% hydrogen by mass. The mass of 158 mL of the gas, measured at 556 mmHg and 25 C, was 0.275 g. What is the molecular formula of the compound?

A gaseous hydrogen- and carbon-containing compound is decomposed and found to contain 85.63% C and 14.37% H by mass. The mass of 258 mL of the gas, measured at STP, was 0.646 g. What is the molecular formula of the compound?

Consider the reaction: 2 NiO(s) S 2 Ni(s) + O2(g) If O 2 is collected over water at 40.0 C and a total pressure of 745 mmHg, what volume of gas is collected for the complete reaction of 24.78 g of NiO?

Consider the reaction: \(2\mathrm{\ Ag}_2\mathrm{O}(s)\rightarrow4\ \mathrm{Ag}(s)+\mathrm{O}_2(g)\) If this reaction produces 15.8 g of Ag(s), what total volume of gas can be collected over water at a temperature of \(25\ ^{\circ}\mathrm{C}\) and a total pressure of 752 mmHg?

When hydrochloric acid is poured over potassium sulfide, 42.9 mL of hydrogen sulfide gas is produced at a pressure of 752 torr and \(25.8 ^\circ C\). Write an equation for the gas-evolution reaction and determine how much potassium sulfide (in grams) reacted.

Consider the reaction: 2 SO2(g) + O2(g) S 2 SO3(g) a. If 285.5 mL of SO 2 reacts with 158.9 mL of O 2 (both measured at 315 K and 50.0 mmHg), what is the limiting reactant and the theoretical yield of SO 3 ? b. If 187.2 mL of SO 3 is collected (measured at 315 K and 50.0 mmHg), what is the percent yield for the reaction?

Ammonium carbonate decomposes upon heating according to the balanced equation: \(\left(\mathrm{NH}_4\right)_2\mathrm{CO}_3(s)\ \rightarrow\ 2\mathrm{\ NH}_3(g)+\mathrm{CO}_2(g)+\mathrm{H}_2\mathrm{O}(g)\) Calculate the total volume of gas produced at \(22\ ^{\circ}\mathrm{C}\) and 1.02 atm by the complete decomposition of 11.83 g of ammonium carbonate.

Ammonium nitrate decomposes explosively upon heating according to the balanced equation: 2 NH4NO3(s) S 2 N2(g) + O2(g) + 4 H2O(g) Calculate the total volume of gas (at 125 C and 748 mmHg) produced by the complete decomposition of 1.55 kg of ammonium nitrate.

Olympic cyclists fill their tires with helium to make them lighter. Calculate the mass of air in an air-filled tire and the mass of helium in a helium-filled tire. What is the mass difference between the two? Assume that the volume of the tire is 855 mL, that it is filled to a total pressure of 125 psi, and that the temperature is 25 C. Also, assume an average molar mass for air of 28.8 g/mol.

In a common classroom demonstration, a balloon is filled with air and submerged in liquid nitrogen. The balloon contracts as the gases within the balloon cool. Suppose a balloon initially contains 2.95 L of air at a temperature of 25.0 C and a pressure of 0.998 atm. Calculate the expected volume of the balloon upon cooling to -196 C (the boiling point of liquid nitrogen). When the demonstration is carried out, the actual volume of the balloon decreases to 0.61 L. How does the observed volume of the balloon compare to your calculated value? Explain the difference.

Gaseous ammonia is injected into the exhaust stream of a coalburning power plant to reduce the pollutant NO to N 2 according to the reaction: 4 NH3(g) + 4 NO(g) + O2(g) S 4 N2(g) + 6 H2O(g) Suppose that the exhaust stream of a power plant has a flow rate of 335 L/s at a temperature of 955 K, and that the exhaust contains a partial pressure of NO of 22.4 torr. What should be the flow rate of ammonia delivered at 755 torr and 298 K into the stream to react completely with the NO if the ammonia is 65.2% pure (by volume)?

The emission of NO 2 by fossil fuel combustion can be prevented by injecting gaseous urea into the combustion mixture. The urea reduces NO (which oxidizes in air to form NO 2 ) according to the reaction: 2 CO( NH2)2(g) + 4 NO(g) + O2(g) S 4 N2(g) + 2 CO2(g) + 4 H2O(g) Suppose that the exhaust stream of an automobile has a flow rate of 2.55 L/s at 655 K and contains a partial pressure of NO of 12.4 torr. What total mass of urea is necessary to react completely with the NO formed during 8.0 hours of driving?

An ordinary gasoline can measuring \(30.0 \mathrm{~cm}\) by \(20.0 \mathrm{~cm}\) by \(15.0 \mathrm{~cm}\) is evacuated with a vacuum pump. Assuming that virtually all of the air can be removed from inside the can, and that atmospheric pressure is \(14.7 \mathrm{psi}\), what is the total force (in pounds) on the surface of the can? Do you think that the can could withstand the force?

Twenty-five milliliters of liquid nitrogen 1density = 0.807 g/mL2 is poured into a cylindrical container with a radius of 10.0 cm and a length of 20.0 cm. The container initially contains only air at a pressure of 760.0 mmHg (atmospheric pressure) and a temperature of 298 K. If the liquid nitrogen completely vaporizes, what is the total force (in lb) on the interior of the container at 298 K?

A 160.0 L helium tank contains pure helium at a pressure of 1855 psi and a temperature of 298 K. How many 3.5 L helium balloons will the helium in the tank fill? (Assume an atmospheric pressure of 1.0 atm and a temperature of 298 K.)

An 11.5 mL sample of liquid butane (density = 0.573 g/mL) is evaporated in an otherwise empty container at a temperature of \(28.5 \ ^\circ C\). The pressure in the container following evaporation is 892 torr. What is the volume of the container?

A scuba diver creates a spherical bubble with a radius of 2.5 cm at a depth of 30.0 m where the total pressure (including atmospheric pressure) is 4.00 atm. What is the radius of the bubble when it reaches the surface of the water? (Assume that the atmospheric pressure is 1.00 atm and the temperature is 298 K.)

A particular balloon can be stretched to a maximum surface area of 1257 cm2 . The balloon is filled with 3.0 L of helium gas at a pressure of 755 torr and a temperature of 298 K. The balloon is then allowed to rise in the atmosphere. If the atmospheric temperature is 273 K, at what pressure will the balloon burst? (Assume the balloon to be in the shape of a sphere.)

A catalytic converter in an automobile uses a palladium or platinum catalyst (a substance that increases the rate of a reaction without being consumed by the reaction) to convert carbon monoxide gas to carbon dioxide according to the reaction: 2 CO(g) + O2(g) S 2 CO2(g) A chemist researching the effectiveness of a new catalyst combines a 2.0:1.0 mole ratio mixture of carbon monoxide and oxygen gas (respectively) over the catalyst in a 2.45 L flask at a total pressure of 745 torr and a temperature of 552 C. When the reaction is complete, the pressure in the flask has dropped to 552 torr. What percentage of the carbon monoxide was converted to carbon dioxide?

A quantity of N 2 occupies a volume of 1.0 L at 300 K and 1.0 atm. The gas expands to a volume of 3.0 L as the result of a change in both temperature and pressure. Find the density of the gas at these new conditions.

A mixture of CO( g ) and O 2 ( g ) in a 1.0 L container at 1.0 * 103 K has a total pressure of 2.2 atm. After some time the total pressure falls to 1.9 atm as the result of the formation of CO 2 . Determine the mass (in grams) of CO 2 that forms.

The radius of a xenon atom is \(1.3 \times 10^{-8} \mathrm{\ cm}\). A 100 mL flask is filled with Xe at a pressure of 1.0 atm and a temperature of 273 K. Calculate the fraction of the volume that is occupied by Xe atoms. (Hint: The atoms are spheres.)

A natural gas storage tank is a cylinder with a moveable top whose volume can change only as its height changes. Its radius remains fixed. The height of the cylinder is 22.6 m on a day when the temperature is 22 C. The next day the height of the cylinder increases to 23.8 m when the gas expands because of a heat wave. Find the temperature on the second day, assuming that the pressure and amount of gas in the storage tank have not changed.

A mixture of 8.0 g CH4 and 8.0 g Xe is placed in a container and the total pressure is found to be 0.44 atm. Determine the partial pressure of CH4 .

A steel container of volume 0.35 L can withstand pressures up to 88 atm before exploding. What mass of helium can be stored in this container at 299 K?

Binary compounds of alkali metals and hydrogen react with water to liberate H2(g) . The H2 from the reaction of a sample of NaH with an excess of water fills a volume of 0.490 L above the water. The temperature of the gas is 35 C and the total pressure is 758 mmHg. Determine the mass of H2 liberated and the mass of NaH that reacted.

In a given diffusion apparatus, 15.0 mL of HBr gas diffused in 1.0 min. In the same apparatus and under the same conditions, 20.3 mL of an unknown gas diffused in 1.0 min. The unknown gas is a hydrocarbon. Find its molecular formula.

A sample of N2O3(g) has a pressure of 0.017 atm. The temperature (in K) is then doubled and the N2O3 undergoes complete decomposition to NO2(g) and NO(g) . Find the total pressure of the mixture of gases assuming constant volume and no additional temperature change.

When 0.583 g of neon is added to an 800 cm3 bulb containing a sample of argon, the total pressure of the gases is 1.17 atm at a temperature of 295 K. Find the mass of the argon in the bulb.

A gas mixture composed of helium and argon has a density of 0.670 g/L at a 755 mmHg and 298 K. What is the composition of the mixture by volume?

A gas mixture contains 75.2% nitrogen and 24.8% krypton by mass. What is the partial pressure of krypton in the mixture if the total pressure is 745 mmHg?

A 10-liter container is filled with 0.10 mol of H2(g) and heated to 3000 K, causing some of the H2(g) to decompose into H( g ). The pressure is found to be 3.0 atm. Find the partial pressure of the H( g ) that forms from H2 at this temperature. ( Assume two significant figures for the temperature.)

A mixture of \(\mathrm{NH}_{3}(g)\) and \(\mathrm{N}_{2} \mathrm{H}_{4}(\mathrm{g})\) is placed in a sealed container at 300 K. The total pressure is 0.50 atm. The container is heated to 1200 K at which time both substances decompose completely according to the equations \(2 \mathrm{NH}_{3}(g) \rightarrow \mathrm{N}_{2}(g)+3 \mathrm{H}_{2}(g)\); \(\mathrm{N}_{2} \mathrm{H}_{4}(g) \rightarrow \mathrm{N}_{2}(g)+2 \mathrm{H}_{2}(g)\). After decomposition is complete the total pressure at 1200 K is found to be 4.5 atm. Find the percent of \(\mathrm{N}_{2} \mathrm{H}_{4}(g)\) in the original mixture. (Assume two significant figures for the temperature.)

A quantity of CO gas occupies a volume of 0.48 L at 1.0 atm and 275 K. The pressure of the gas is lowered and its temperature is raised until its volume is 1.3 L. Determine the density of the CO under the new conditions.

When CO2(g) is put in a sealed container at 701 K and a pressure of 10.0 atm and is heated to 1401 K, the pressure rises to 22.5 atm. Some of the CO 2 decomposes to CO and O 2 . Calculate the mole percent of CO 2 that decomposes.

The world burns approximately \(3.5 \times 10^{12} \mathrm{\ kg}\) of fossil fuel per year. Use the combustion of octane as the representative reaction and determine the mass of carbon dioxide (the most significant greenhouse gas) formed per year. The current concentration of carbon dioxide in the atmosphere is approximately 387 ppm (by volume). By what percentage does the concentration increase each year due to fossil fuel combustion? Approximate the average properties of the entire atmosphere by assuming that the atmosphere extends from sea level to 15 km and that it has an average pressure of 381 torr and average temperature of 275 K. Assume Earth is a perfect sphere with a radius of 6371 km.

The atmosphere slowly oxidizes hydrocarbons in a number of steps that eventually convert the hydrocarbon into carbon dioxide and water. The overall reaction of a number of such steps for methane gas is CH4(g) + 5 O2(g) + 5 NO(g) S CO2(g) + H2O(g) + 5 NO2(g) + 2 OH(g) Suppose that an atmospheric chemist combines 155 mL of methane at STP, 885 mL of oxygen at STP, and 55.5 mL of NO at STP in a 2.0 L flask. The flask is allowed to stand for several weeks at 275 K. If the reaction reaches 90.0% of completion (90.0% of the limiting reactant is consumed), what is the partial pressure of each of the reactants and products in the flask at 275 K? What is the total pressure in the flask?

Two identical balloons are filled to the same volume, one with air and one with helium. The next day, the volume of the air-filled balloon has decreased by 5.0%. By what percent has the volume of the helium-filled balloon decreased? (Assume that the air is four-fifths nitrogen and one-fifth oxygen and that the temperature did not change.)

A mixture of CH4(g) and C2H6(g) has a total pressure of 0.53 atm. Just enough O2(g) is added to the mixture to bring about its complete combustion to CO2(g) and H2O(g) . The total pressure of the two product gases is found to be 2.2 atm. Assuming constant volume and temperature, find the mole fraction of CH4 in the mixture.

A sample of C2H2(g) has a pressure of 7.8 kPa. After some time a portion of it reacts to form C6H6(g) . The total pressure of the mixture of gases is then 3.9 kPa. Assume the volume and the temperature do not change. What fraction of C2H2(g) has undergone reaction?

When the driver of an automobile applies the brakes, the passengers are pushed toward the front of the car, but a helium balloon is pushed toward the back of the car. Upon forward acceleration, the passengers are pushed toward the back of the car, but the helium balloon is pushed toward the front of the car. Why?

Suppose that a liquid is ten times denser than water. If you were to sip this liquid at sea level using a straw, what is the maximum length your straw can be?

The reaction occurs in a closed container: A(g) + 2 B(g) S 2 C(g) A reaction mixture initially contains 1.5 L of A and 2.0 L of B. Assuming that the volume and temperature of the reaction mixture remain constant, what is the percent change in pressure if the reaction goes to completion?

One mole of nitrogen and one mole of neon are combined in a closed container at STP. How big is the container?

Exactly equal amounts (in moles) of gas A and gas B are combined in a 1 L container at room temperature. Gas B has a molar mass that is twice that of gas A. Which statement is true for the mixture of gases and why? a. The molecules of gas B have greater kinetic energy than those of gas A. b. Gas B has a greater partial pressure than gas A. c. The molecules of gas B have a greater average velocity than those of gas A. d. Gas B makes a greater contribution to the average density of the mixture than gas A.

Which gas would you expect to deviate most from ideal behavior under conditions of low temperature: F 2 , Cl 2 , or Br 2 ? Explain.

The volume of a sample of a fixed amount of gas is decreased from 2.0 L to 1.0 L. The temperature of the gas in kelvins is then doubled. What is the final pressure of the gas in terms of the initial pressure?

Which gas sample has the greatest volume at STP? a. 10.0 g Kr b. 10.0 g Xe c. 10.0 g He

Draw a depiction of a gas sample, as described by kinetic molecular theory, containing equal molar amounts of helium, neon, and krypton. Use different color dots to represent each element. Give each atom a “tail” to represent its velocity relative to the others in the mixture.