Solved: The sun supplies energy at a rate of about 1.0

Objects placed together eventually reach the same temperature.When you go into a room and touch a piece of metal in thatroom, it feels colder than a piece of plastic. Explain.

What is meant by the term lower in energy? Which is lower inenergy, a mixture of hydrogen and oxygen gases or liquid water?How do you know? Which of the two is more stable? Howdo you know?

A fire is started in a fireplace by striking a match and lightingcrumpled paper under some logs. Explain all the energy transfersin this scenario using the terms exothermic, endothermic,system, surroundings, potential energy, and kinetic energy in thediscussion.

Liquid water turns to ice. Is this process endothermic or exothermic?Explain what is occurring using the terms system,surroundings, heat, potential energy, and kinetic energy in thediscussion.

Consider the following statements: Heat is a form of energy,and energy is conserved. The heat lost by a system must be equalto the amount of heat gained by the surroundings. Therefore,heat is conserved. Indicate everything you think is correctin these statements. Indicate everything you think is incorrect.Correct the incorrect statements and explain.

Consider 5.5 L of a gas at a pressure of 3.0 atm in a cylinderwith a movable piston. The external pressure is changed so thatthe volume changes to 10.5 L.a. Calculate the work done, and indicate the correct sign.b. Use the preceding data but consider the process to occur intwo steps. At the end of the first step, the volume is 7.0 L.The second step results in a final volume of 10.5 L. Calculatethe work done, and indicate the correct sign.c. Calculate the work done if after the first step the volume is8.0 L and the second step leads to a volume of 10.5 L. Doesthe work differ from that in part b? Explain.

In Question 6 the work calculated for the different conditions inthe various parts of the question was different even though thesystem had the same initial and final conditions. Based on thisinformation, is work a state function?a. Explain how you know that work is not a state function.b. Why does the work increase with an increase in the numberof steps?c. Which two-step process resulted in more work, when the firststep had the bigger change in volume or when the second stephad the bigger change in volume? Explain.

Photosynthetic plants use the following reaction to produceglucose, cellulose, and so forth:How might extensive destruction of forests exacerbate the greenhouseeffect?

Consider an airplane trip from Chicago, Illinois to Denver,Colorado. List some path-dependent functions and some statefunctions for the plane trip

How is average bond strength related to relative potential energiesof the reactants and the products?

Assuming gasoline is pure C8H18(l), predict the signs of q andw for the process of combusting gasoline into CO2(g) andH2O(g).

What is the difference between _H and _E?

The enthalpy of combustion of CH4(g) when H2O(l) is formedis _891 kJ/mol and the enthalpy of combustion of CH4(g) whenH2O(g) is formed is _803 kJ/mol. Use these data and Hesss lawto determine the enthalpy of vaporization for water.6CO21g2 _ 6H2O1l2 ! SunlightC6H12O61s2 _ 6O21g2

Standard enthalpies of formation are relative values. What are_Hf values relative to?

What is incomplete combustion of fossil fuels? Why can this bea problem?

Explain the advantages and disadvantages of hydrogen as analternative fuel.

Calculate the kinetic energy of a baseball (mass _ 5.25 oz) witha velocity of 1.0 _ 102 mi/h.

Calculate the kinetic energy of a 1.0 _ 10_5-g object with avelocity of 2.0 _ 105 cm/s.

Which has the greater kinetic energy, an object with a mass of2.0 kg and a velocity of 1.0 m/s or an object with a mass of1.0 kg and a velocity of 2.0 m/s?

Consider the accompanying diagram. Ball A is allowed to falland strike ball B. Assume that all of ball As energy is transferredto ball B, at point I, and that there is no loss of energy to othersources. What is the kinetic energy and the potential energy ofball B at point II? The potential energy is given by PE _ mgz,where m is the mass in kilograms, g is the gravitational constant(9.81 m/s2), and z is the distance in meters.

Calculate _E for each of the following.a. q _ _47 kJ, w _ _88 kJb. q _ _82 kJ, w _ _47 kJc. q _ _47 kJ, w _ 0d. In which of these cases do the surroundings do work on thesystem?

A system undergoes a process consisting of the following two steps:Step 1: The system absorbs 72 J of heat while 35 J of work isdone on it.Step 2: The system absorbs 35 J of heat while performing 72 Jof work.Calculate _E for the overall process.

If the internal energy of a thermodynamic system is increasedby 300. J while 75 J of expansion work is done, how much heatwas transferred and in which direction, to or from the system?

Calculate the internal energy change for each of the following.a. One hundred (100.) joules of work are required to compressa gas. At the same time, the gas releases 23 J of heat.b. A piston is compressed from a volume of 8.30 L to 2.80 Lagainst a constant pressure of 1.90 atm. In the process, thereis a heat gain by the system of 350. J.c. A piston expands against 1.00 atm of pressure from 11.2 Lto 29.1 L. In the process, 1037 J of heat is absorbed.

A sample of an ideal gas at 15.0 atm and 10.0 L is allowed toexpand against a constant external pressure of 2.00 atm at aconstant temperature. Calculate the work in units of kJ for thegas expansion. (Hint: Boyles law applies.)

A piston performs work of 210. L atm on the surroundings, whilethe cylinder in which it is placed expands from 10. L to 25 L.At the same time, 45 J of heat is transferred from the surroundingsto the system. Against what pressure was the pistonworking?

Consider a mixture of air and gasoline vapor in a cylinder witha piston. The original volume is 40. cm3. If the combustion ofthis mixture releases 950. J of energy, to what volume will thegases expand against a constant pressure of 650. torr if all theenergy of combustion is converted into work to push backthe piston?

As a system increases in volume, it absorbs 52.5 J of energy inthe form of heat from the surroundings. The piston is workingagainst a pressure of 0.500 atm. The final volume of the systemis 58.0 L. What was the initial volume of the system if the internalenergy of the system decreased by 102.5 J?

A balloon filled with 39.1 mol helium has a volume of 876 L at0.0_C and 1.00 atm pressure. The temperature of the balloon isincreased to 38.0_C as it expands to a volume of 998 L, the pressureremaining constant. Calculate q, w, and _E for the heliumin the balloon. (The molar heat capacity for helium gas is.)

One mole of H2O(g) at 1.00 atm and 100._C occupies a volumeof 30.6 L. When one mole of H2O(g) is condensed to one moleof H2O(l) at 1.00 atm and 100._C, 40.66 kJ of heat is released.If the density of H2O(l) at this temperature and pressure is0.996 g/cm3, calculate _E for the condensation of one mole ofwater at 1.00 atm and 100._C.

One of the components of polluted air is NO. It is formed in thehigh-temperature environment of internal combustion engines bythe following reaction:Why are high temperatures needed to convert N2 and O2 to NO?N21g2 _ O21g2!2NO1g2 H _ 180 kJ20.8 J/C _ mol

The reactionis the last step in the commercial production of sulfuric acid. Theenthalpy change for this reaction is _227 kJ. In designing a sulfuricacid plant, is it necessary to provide for heating or coolingof the reaction mixture? Explain.

Are the following processes exothermic or endothermic?a. When solid KBr is dissolved in water, the solution getscolder.b. Natural gas (CH4) is burned in a furnace.c. When concentrated H2SO4 is added to water, the solution getsvery hot.d. Water is boiled in a teakettle.

Are the following processes exothermic or endothermic?a. the combustion of gasoline in a car engineb. water condensing on a cold pipec.d.

The overall reaction in a commercial heat pack can be representedasa. How much heat is released when 4.00 mol iron is reacted withexcess O2?b. How much heat is released when 1.00 mol Fe2O3 is produced?c. How much heat is released when 1.00 g iron is reacted withexcess O2?d. How much heat is released when 10.0 g Fe and 2.00 g O2 arereacted?

Consider the following reaction:a. How much heat is evolved for the production of 1.00 mol ofH2O(l )?b. How much heat is evolved when 4.03 g of hydrogen is reactedwith excess oxygen?c. How much heat is evolved when 186 g of oxygen is reactedwih excess hydrogen?d. The total volume of hydrogen gas needed to fill the Hindenburgwas 2.0 _ 108 L at 1.0 atm and 25_C. How much heatwas evolved when the Hindenburg exploded, assuming all ofthe hydrogen reacted?

Consider the combustion of propane:Assume that all the heat in Sample Exercise 6.3 comes from thecombustion of propane. What mass of propane must be burnedto furnish this amount of energy assuming the heat transferprocess is 60.% efficient?

Consider the following reaction:Calculate the enthalpy change for each of the following cases:a. 1.00 g methane is burned in excess oxygen.b. 1.00 _ 103 L methane gas at 740. torr and 25_C is burned inexcess oxygen.

For the process at 298 K and 1.0 atm, _His more positive than _E by 2.5 kJ/mol. What does the 2.5 kJ/molquantity represent?

For the following reactions at constant pressure, predict if _H __E, _H _ _E, or _H _ _E.a.b.c.

Consider the substances in Table 6.1. Which substance requiresthe largest amount of energy to raise the temperature of 25.0 gof the substance from 15.0_C to 37.0_C? Calculate the energy.Which substance in Table 6.1 has the largest temperature changewhen 550. g of the substance absorbs 10.7 kJ of energy?Calculate the temperature change.

The specific heat capacity of silver isa. Calculate the energy required to raise the temperature of150.0 g Ag from 273 K to 298 K.b. Calculate the energy required to raise the temperature of1.0 mol Ag by 1.0_C (called the molar heat capacity ofsilver).c. It takes 1.25 kJ of energy to heat a sample of pure silverfrom 12.0_C to 15.2_C. Calculate the mass of the sample ofsilver.

A 5.00-g sample of one of the substances listed in Table 6.1 washeated from 25.2_C to 55.1_C, requiring 133 J to do so. Whatsubstance was it?

It takes 585 J of energy to raise the temperature of 125.6 g mercuryfrom 20.0_C to 53.5_C. Calculate the specific heat capacityand the molar heat capacity of mercury.

A 30.0-g sample of water at 280. K is mixed with 50.0 g of waterat 330. K. Calculate the final temperature of the mixtureassuming no heat loss to the surroundings.

A biology experiment requires the preparation of a water bathat 37.0_C (body temperature). The temperature of the cold tapwater is 22.0_C, and the temperature of the hot tap water is55.0_C. If a student starts with 90.0 g of cold water, what massof hot water must be added to reach 37.0_C?

A 5.00-g sample of aluminum pellets (specific heat capacity _0.89 J/_C g) and a 10.00-g sample of iron pellets (specificheat capacity _0.45 J/_C g) are heated to 100.0_C. The mixtureof hot iron and aluminum is then dropped into 97.3 g of waterat 22.0_C. Calculate the final temperature of the metal and watermixture, assuming no heat loss to the surroundings.

Hydrogen gives off 120. J/g of energy when burned in oxygen,and methane gives off 50. J/g under the same circumstances.If a mixture of 5.0 g of hydrogen and 10. g of methaneis burned, and the heat released is transferred to 50.0 g of waterat 25.0_C, what final temperature will be reached by the water?

A 150.0-g sample of a metal at 75.0_C is added to 150.0 g ofH2O at 15.0_C. The temperature of the water rises to 18.3_C.Calculate the specific heat capacity of the metal, assuming thatall the heat lost by the metal is gained by the water.__0.24 J/C _ g.4NH31g2 _ 5O21g2!4NO1g2 _ 6H2O1g2N21g2 _ 3H21g2!2NH31g22HF1g2!H21g2 _ F21g2H2O1l2!H2O1g2

A 110.-g sample of copper (specific heat capacity _ 0.20 J/_Cg) is heated to 82.4_C and then placed in a container of water at22.3_C. The final temperature of the water and copper is 24.9_C.What is the mass of the water in the container, assuming that allthe heat lost by the copper is gained by the water?

In a coffee-cup calorimeter, 50.0 mL of 0.100 M AgNO3 and50.0 mL of 0.100 M HCl are mixed to yield the followingreaction:The two solutions were initially at 22.60_C, and the final temperatureis 23.40_C. Calculate the heat that accompanies thisreaction in kJ/mol of AgCl formed. Assume that the combinedsolution has a mass of 100.0 g and a specific heat capacity of4.18 J/_C g.

In a coffee-cup calorimeter, 1.60 g of NH4NO3 is mixed with75.0 g of water at an initial temperature of 25.00_C. After dissolutionof the salt, the final temperature of the calorimeter contentsis 23.34_C. Assuming the solution has a heat capacity of4.18 J/_C g and assuming no heat loss to the calorimeter, calculatethe enthalpy change for the dissolution of NH4NO3 in unitsof kJ/mol.

Consider the dissolution of CaCl2:An 11.0-g sample of CaCl2 is dissolved in 125 g of water, withboth substances at 25.0_C. Calculate the final temperature of thesolution assuming no heat lost to the surroundings and assumingthe solution has a specific heat capacity of 4.18 J/_C g.

Consider the reactionCalculate the heat when 100.0 mL of 0.500 M HCl is mixed with300.0 mL of 0.100 M Ba(OH)2. Assuming that the temperature ofboth solutions was initially 25.0_C and that the final mixture hasa mass of 400.0 g and a specific heat capacity of 4.18 J/_C g,calculate the final temperature of the mixture.

The heat capacity of a bomb calorimeter was determined by burning6.79 g of methane (energy of combustion _ _802 kJ/molCH4) in the bomb. The temperature changed by 10.8_C.a. What is the heat capacity of the bomb?b. A 12.6-g sample of acetylene, C2H2, produced a temperatureincrease of 16.9_C in the same calorimeter. What is the energyof combustion of acetylene (in kJ/mol)?

A 0.1964-g sample of quinone (C6H4O2) is burned in a bombcalorimeter that has a heat capacity of 1.56 kJ/_C. The temperatureof the calorimeter increases by 3.2_C. Calculate the energyof combustion of quinone per gram and per mole.

The enthalpy of combustion of solid carbon to form carbon dioxideis _393.7 kJ/mol carbon, and the enthalpy of combustion ofcarbon monoxide to form carbon dioxide is _283.3 kJ/mol CO.Use these data to calculate _H for the reaction2C1s2 _ O21g2!2CO1g2

Combustion reactions involve reacting a substance with oxygen.When compounds containing carbon and hydrogen are combusted,carbon dioxide and water are the products. Using the enthalpiesof combustion for C4H4 (_2341 kJ/mol), C4H8 (_2755 kJ/mol),and H2 (_286 kJ/mol), calculate _H for the reaction

Given the following datacalculate _H for the reactionOn the basis of the enthalpy change, is this a useful reaction forthe synthesis of ammonia?

Given the following datacalculate _H for the reaction

Given the following datacalculate _H for the reaction

The bombardier beetle uses an explosive discharge as a defensivemeasure. The chemical reaction involved is the oxidationof hydroquinone by hydrogen peroxide to producequinone and water:Calculate _H for this reaction from the following data:

Given the following datacalculate _H for the reactionCaC21s2 _ 2H2O1l2!Ca1OH221aq2 _ C2H21g2C1graphite2 _ O21g2!CO21g2 H _ _393.5 kJC2H21g2 _ 52O21g2!2CO21g2 _ H2O1l2 H _ _1300. kJCaO1s2 _ H2O1l2!Ca1OH221aq2 H _ _653.1 kJCa1s2 _ 12O21g2!CaO1s2 H _ _635.5 kJCa1s2 _ 2C1graphite2!CaC21s2 H _ _62.8 kJH2O1g2!H2O1l2 H _ _43.8 kJH21g2 _ 12O21g2!H2O1g2 H _ _241.8 kJH21g2 _ O21g2!H2O21aq2 H _ _191.2 kJH _ _177.4 kJC6H41OH221aq2!C6H4O21aq2 _ H21g2C6H41OH221aq2 _ H2O21aq2!C6H4O21aq2 _ 2H2O1l2NO1g2 _ O1g2!NO21g2NO1g2 _ O31g2!NO21g2 _ O21g2 H _ _199 kJO21g2!2O1g2 H _ _495 kJ2O31g2!3O21g2 H _ _427 kJClF1g2 _ F21g2!ClF31g22F21g2 _ O21g2!2F2O1g2 H _ _43.4 kJ2ClF31g2 _ 2O21g2!Cl2O1g2 _ 3F2O1g2 H _ 341.4 kJ2ClF1g2 _ O21g2!Cl2O1g2 _ F2O1g2 H _ 167.4 kJ2N21g2 _ 6H2O1g2!3O21g2 _ 4NH31g22H21g2 _ O21g2!2H2O1g2 H _ _484 kJNH31g2!12N21g2 _ 32H21g2 H _ 46 kJC4H41g2 _ 2H21g2!C4H81g2

Given the following datacalculate _H for the reaction

Give the definition of the standard enthalpy of formation for asubstance. Write separate reactions for the formation of NaCl,H2O, C6H12O6, and PbSO4 that have _H_ values equal to _Hf_for each compound.

Write reactions for which the enthalpy change will bea. _Hf_ for solid aluminum oxide.b. The standard enthalpy of combustion of liquid ethanol,C2H5OH(l ).c. The standard enthalpy of neutralization of sodium hydroxidesolution by hydrochloric acid.d. _Hf _ for gaseous vinyl chloride, C2H3Cl(g).e. The enthalpy of combustion of liquid benzene, C6H6(l ).f. The enthalpy of solution of solid ammonium bromide.

Use the values of _Hf_ in Appendix 4 to calculate _H_ for thefollowing reactions.a.b.c.

Use the values of _Hf_ in Appendix 4 to calculate _H_ for thefollowing reactions. (See Exercise 67.)a.b.c.

The Ostwald process for the commercial production of nitric acidfrom ammonia and oxygen involves the following steps:a. Use the values of _H_f in Appendix 4 to calculate the valueof _H_ for each of the preceding reactions.b. Write the overall equation for the production of nitric acid bythe Ostwald process by combining the preceding equations.(Water is also a product.) Is the overall reaction exothermic orendothermic?3NO21g2 _ H2O1l2!2HNO31aq2 _ NO1g22NO1g2 _ O21g2!2NO21g24NH31g2 _ 5O21g2!4NO1g2 _ 6H2O1g2MgO1s2 _ H2O1l2!Mg1OH221s2SiCl41l2 _ 2H2O1l2!SiO21s2 _ 4HCl1aq2(l) + (g) (g) + (g)NH31g2 _ HCl1g2!NH4Cl1s2Ca31PO4221s2 _ 3H2SO41l2!3CaSO41s2 _ 2H3PO41l2(g) + (g) + (g)

Calculate _H_ for each of the following reactions using the datain Appendix 4:Explain why a water or carbon dioxide fire extinguisher mightnot be effective in putting out a sodium fire.

The reusable booster rockets of the space shuttle use a mixtureof aluminum and ammonium perchlorate as fuel. A possiblereaction isCalculate _H_ for this reaction.

The space shuttle orbiter utilizes the oxidation of methylhydrazineby dinitrogen tetroxide for propulsion:Calculate _H_ for this reaction.

Consider the reactionCalculate _Hf_ for ClF3(g).

The standard enthalpy of combustion of ethene gas, C2H4(g),is _1411.1 kJ/mol at 298 K. Given the following enthalpies offormation, calculate _Hf_ for C2H4(g).

Ethanol (C2H5OH) has been proposed as an alternative fuel.Calculate the standard of enthalpy of combustion per gram ofliquid ethanol.

Methanol (CH3OH) has also been proposed as an alternativefuel. Calculate the standard enthalpy of combustion per gramof liquid methanol and compare this answer to that for ethanolin Exercise 75.

Some automobiles and buses have been equipped to burn propane(C3H8). Compare the amounts of energy that can be obtained pergram of C3H8(g) and per gram of gasoline, assuming that gasolineis pure octane, C8H18(l). (See Sample Exercise 6.11.) Lookup the boiling point of propane. What disadvantages are there tousing propane instead of gasoline as a fuel?

Acetylene (C2H2) and butane (C4H10) are gaseous fuels with enthalpiesof combustion of _49.9 kJ/g and _49.5 kJ/g, respectively.Compare the energy available from the combustion of a given volumeof acetylene to the combustion energy from the same volumeof butane at the same temperature and pressure.

Assume that 4.19 _ 106 kJ of energy is needed to heat a home.If this energy is derived from the combustion of methane(CH4), what volume of methane, measured at STP, mustbe burned? (_H_combustion for CH4 _ _891 kJ/mol)H2O1l2 _285.8 kJ/molCO21g2 _393.5 kJ/molH _ _1196 kJ2ClF31g2 _ 2NH31g2!N21g2 _ 6HF1g2 _ Cl21g24N2H3CH31l2 _ 5N2O41l2!12H2O1g2 _ 9N21g2 _ 4CO21g2!Al2O31s2 _ AlCl31s2 _ 3NO1g2 _ 6H2O1g23Al1s2 _ 3NH4ClO41s22Na1s2 _ CO21g2!Na2O1s2 _ CO1g22Na1s2 _ 2H2O1l2!2NaOH1aq2 _ H21g24Na1s2 _ O21g2!2Na2O1s2

The complete combustion of acetylene, C2H2(g), produces 1300. kJof energy per mole of acetylene consumed. How many gramsof acetylene must be burned to produce enough heat to raise thetemperature of 1.00 gal of water by 10.0_C if the process is 80.0%efficient? Assume the density of water is 1.00 g/cm3.

Three gas-phase reactions were run in a constant-pressure pistonapparatus as illustrated below. For each reaction, give the balancedreaction and predict the sign of w (the work done) for thereaction.If just the balanced reactions were given, how could you predictthe sign of w for a reaction?

Consider the following changes:a.b.c.d.e.At constant temperature and pressure, in which of thesechanges is work done by the system on the surroundings? Bythe surroundings on the system? In which of them is no workdone?

Consider the following cyclic process carried out in two stepson a gas:Step 1: 45 J of heat is added to the gas, and 10. J of expansionwork is performed.Step 2: 60. J of heat is removed from the gas as the gas is compressedback to the initial state.Calculate the work for the gas compression in Step 2.

Calculate _H_ for the reactionA 5.00-g chunk of potassium is dropped into 1.00 kg water at24.0_C. What is the final temperature of the water after the precedingreaction occurs? Assume that all the heat is used to raisethe temperature of the water. (Never run this reaction. It is verydangerous; it bursts into flame!)

The enthalpy of neutralization for the reaction of a strong acidwith a strong base is _56 kJ/mol of water produced. How muchenergy will be released when 200.0 mL of 0.400 M HCl is mixedwith 150.0 mL of 0.500 M NaOH?

When 1.00 L of 2.00 M Na2SO4 solution at 30.0_C is added to2.00 L of 0.750 M Ba(NO3)2 solution at 30.0_C in a calorimeter,a white solid (BaSO4) forms. The temperature of the mixtureincreases to 42.0_C. Assuming that the specific heat capacity ofthe solution is 6.37 J/_C g and that the density of the finalsolution is 2.00 g/mL, calculate the enthalpy change per mole ofBaSO4 formed.

If a student performs an endothermic reaction in a calorimeter,how does the calculated value of _H differ from the actual valueif the heat exchanged with the calorimeter is not taken intoaccount?

In a bomb calorimeter, the reaction vessel is surrounded by waterthat must be added for each experiment. Since the amount ofwater is not constant from experiment to experiment, the massof water must be measured in each case. The heat capacity ofthe calorimeter is broken down into two parts: the water and thecalorimeter components. If a calorimeter contains 1.00 kg waterand has a total heat capacity of 10.84 kJ/_C, what is the heatcapacity of the calorimeter components?

The bomb calorimeter in Exercise 88 is filled with 987 g of water.The initial temperature of the calorimeter contents is 23.32_C.A 1.056-g sample of benzoic acid (_Ecomb _ _26.42 kJ/g) iscombusted in the calorimeter. What is the final temperature ofthe calorimeter contents?

Given the following datacalculate _H_ for the reaction

At 298 K, the standard enthalpies of formation for C2H2(g) andC6H6(l) are 227 kJ/mol and 49 kJ/mol, respectively.a. Calculate _H_ forC6H61l2!3C2H21g2b. Both acetylene (C2H2) and benzene (C6H6) can be used as fuels.Which compound would liberate more energy per gramwhen combusted in air?

Using the following data, calculate the standard heat of formationof ICl(g) in kJ/mol:

Calculate _H_ for each of the following reactions, which occurin the atmosphere.a.b.c.d.

Consider 2.00 mol of an ideal gas that is taken from state A (PA _2.00 atm, VA _ 10.0 L) to state B (PB _ 1.00 atm, VB _ 30.0 L)by two different pathways:These pathways are summarized on the following graph ofP versus V:Calculate the work (in units of J) associated with the two pathways.Is work a state function? Explain.

Combustion of table sugar produces CO2(g) and H2O(l). When1.46 g of table sugar is combusted in a constant-volume (bomb)calorimeter, 24.00 kJ of heat is liberated.a. Assuming that table sugar is pure sucrose, C12H22O11(s), writethe balanced equation for the combustion reaction.b. Calculate _E in kJ/mol C12H22O11 for the combustion reactionof sucrose.c. Calculate _H in kJ/mol C12H22O11 for the combustion reactionof sucrose at 25_C.

The sun supplies energy at a rate of about 1.0 kilowatt per squaremeter of surface area (1 watt _ 1 J/s). The plants in an agriculturalfield produce the equivalent of 20. kg of sucrose (C12H22O11)per hour per hectare (1 ha _ 10,000 m2). Assuming that sucroseis produced by the reactioncalculate the percentage of sunlight used to produce the sucrosethat is, determine the efficiency of photosynthesis.

The best solar panels currently available are about 13% efficientin converting sunlight to electricity. A typical home will useabout 40. kWh of electricity per day (1 kWh _ 1 kilowatt hour;1 kW _ 1000 J/s). Assuming 8.0 hours of useful sunlight perday, calculate the minimum solar panel surface area necessaryto provide all of a typical homes electricity. (See Exercise 96for the energy rate supplied by the sun.)

On Easter Sunday, April 3, 1983, nitric acid spilled from a tankcar near downtown Denver, Colorado. The spill was neutralizedwith sodium carbonate:a. Calculate _H_ for this reaction. Approximately 2.0 _ 104 galnitric acid was spilled. Assume that the acid was an aqueoussolution containing 70.0% HNO3 by mass with a density of1.42 g/cm3. How much sodium carbonate was required forcomplete neutralization of the spill, and how much heat wasevolved? (_Hf_ for NaNO3(aq)_ _467 kJ/mol)b. According to The Denver Post for April 4, 1983, authoritiesfeared that dangerous air pollution might occur during theneutralization. Considering the magnitude of _H_, what wastheir major concern?

A piece of chocolate cake contains about 400 Calories. A nutritionalCalorie is equal to 1000 calories (thermochemical calories),which is equal to 4.184 kJ. How many 8-in-high steps musta 180-lb man climb to expend the 400 Cal from the piece ofcake? See Exercise 20 for the formula for potential energy.

The standard enthalpy of formation of H2O(l) at 298 K is_285.8 kJ/mol. Calculate the change in internal energy for thefollowing process at 298 K and 1 atm:(Hint: Using the ideal gas equation, derive an expression forwork in terms of n, R, and T.)

You have a 1.00-mol sample of water at _30._C and you heat ituntil you have gaseous water at 140._C. Calculate q for the entireprocess. Use the following data.H2O1l2!H2O1g2 Hvaporization _ 40.7 kJ_mol 1at 100.C2H2O1s2!H2O1l2 Hfusion _ 6.02 kJ_mol 1at 0C2Specific heat capacity of steam _ 2.02 J_C _ gSpecific heat capacity of water _ 4.18 J_C _ gSpecific heat capacity of ice _ 2.03 J_C _ gH2O1l2!H21g2 _ 12O21g2 E _ ?2HNO31aq2 _ Na2CO31s2!2NaNO31aq2 _ H2O1l2 _ CO21g2H _ 5640 kJ12CO21g2 _ 11H2O1l2!C12H22O111s2 _ 12O21g2

A 500.0-g sample of an element at 195_C is dropped into anicewater mixture; 109.5 g of ice melts and an icewater mixtureremains. Calculate the specific heat of the element. SeeExercise 101 for pertinent information.

The preparation of NO2(g) from N2(g) and O2(g) is an endothermicreaction:The enthalpy change of reaction for the balanced equation (withlowest whole-number coefficients) is _H _ 67.7 kJ. If 2.50 _102 mL of N2(g) at 100._C and 3.50 atm and 4.50 _ 102 mL ofO2(g) at 100._C and 3.50 atm are mixed, what amount of heat isnecessary to synthesize NO2(g)?

Nitromethane, CH3NO2, can be used as a fuel. When the liquidis burned, the (unbalanced) reaction is mainlya. The standard enthalpy change of reaction (_H_rxn) for the balancedreaction (with lowest whole-number coefficients) is_1288.5 kJ. Calculate the _H_f for nitromethane.b. A 15.0-L flask containing a sample of nitromethane is filledwith O2 and the flask is heated to 100.C. At this temperature,and after the reaction is complete, the total pressure ofall the gases inside the flask is 950. torr. If the mole fractionof nitrogen ( ) is 0.134 after the reaction is complete,what mass of nitrogen was produced?

A cubic piece of uranium metal (specific heat capacity _) at 200.0_C is dropped into 1.00 L of deuteriumoxide (heavy water, specific heat capacityat 25.5_C. The final temperature of the uranium and deuteriumoxide mixture is 28.5_C. Given the densities of uranium(19.05 g/cm3) and deuterium oxide (1.11 g/mL), what is theedge length of the cube of uranium?

A sample consisting of 22.7 g of a nongaseous, unstable compoundX is placed inside a metal cylinder with a radius of8.00 cm, and a piston is carefully placed on the surface of thecompound so that, for all practical purposes, the distance betweenthe bottom of the cylinder and the piston is zero. (A holein the piston allows trapped air to escape as the piston is placedon the compound; then this hole is plugged so that nothing in-