Solved: Your laboratory assignment for the week is to

What is the first law of thermodynamics?

How is work done on a gas?

What is heat?

How is heat transferred?

What are some thermal properties of matter?

Why is the first law important?

A gas cylinder and piston Insulation are covered with heavy insulation. The piston is pushed into the cylinder, compressing the gas. In this process the gas temperature a. Increases. b. Decreases. c. Doesnt change. d. Theres not sufficient information to te

How much work is done in the ideal-gas process of Figure 19.6?

A cylinder contains 7.0 g of nitrogen gas. How much work must be done to compress the gas at a constant temperature of 80C until the volume is halved?

Two processes take an ideal p gas from state 1 to state 3. Compare the work done by process A to the work done by process B. a. WA = WB = 0 b. WA = WB but neither is zero c. WA 7 WB d. WA 6 WB

Which one or more of the following processes involves heat? a. The brakes in your car get hot when you stop. b. A steel block is held over a candle. c. You push a rigid cylinder of gas across a frictionless surface. d. You push a piston into a cylinder of gas, increasing the temperature of the gas. e. You place a cylinder of gas in hot water. The gas expands, causing a piston to rise and lift a weight. The temperature of the gas does not change.

A 70 kg student catches the flu, and his body temperature increases from 37.0C 198.6F2 to 39.0C 1102.2F2. How much energy is required to raise his bodys temperature? The specific heat of a mammalian body is 3400 J/kg K, nearly that of water because mammals are mostly water

Which first-law bar chart describes the process shown in the pV diagram?

An insulated jar containing 200 g of solid candle wax is placed on a hot plate that supplies heat energy to the wax at the rate of 220 J/s. The wax temperature is measured every 30 s, yielding the following data: What are the specific heat of the solid wax, the melting point, and the waxs heat of fusion?

Objects A and B are brought into close thermal contact with each other, but they are well isolated from their surroundings. Initially TA = 0C and TB = 100C. The specific heat of A is less than the specific heat of B. The two objects will soon reach a common final temperature Tf. The final temperature is a. Tf 7 50C b. Tf = 50C c. Tf 6 50C

Your 500 mL soda is at 20C, room temperature, so you add 100 g of ice from the -20C freezer. Does all the ice melt? If so, what is the final temperature? If not, what fraction of the ice melts? Assume that you have a well-insulated cup

A 200 g piece of iron at 120C and a 150 g piece of copper at -50C are dropped into an insulated beaker containing 300 g of ethyl alcohol at 20C. What is the final temperature?

For the two processes shown, which of the following is true: a. QA 7 QB b. QA = QB c. QA 6 QB

Three moles of O2 gas are at 20.0C. 600 J of heat energy are transferred to the gas at constant pressure, then 600 J are removed at constant volume. What is the final temperature? Show the process on a pV diagram.

The interior volume of a 200 g hollow aluminum box is 800 cm3 . The box contains nitrogen gas at STP. A 20 cm3 block of copper at a temperature of 300C is placed inside the box, then the box is sealed. What is the final temperature?

Air containing gasoline vapor is admitted into the cylinder of an internal combustion engine at 1.00 atm pressure and 30C. The piston rapidly compresses the gas from 500 cm3 to 50 cm3 , a compression ratio of 10. a. What are the final temperature and pressure of the gas? b. Show the compression process on a pV diagram. c. How much work is done to compress the gas?

A 1.8-m-wide by 1.0-m-tall by 0.65-m-deep home freezer is insulated with 5.0-cm-thick Styrofoam insulation. At what rate must the compressor remove heat from the freezer to keep the inside at -20C in a room where the air temperature is 25C?

The radius of the sun is 6.96 * 108 m. At the distance of the earth, 1.50 * 1011 m, the intensity of solar radiation (measured by satellites above the atmosphere) is 1370 W/m2 . What is the temperature of the suns surface?

400 mL of water is poured into a covered 8.0@cm@diameter, 150 g glass beaker with a 2.0@mm@thick bottom; then the beaker is placed on a 400C hot plate. Once the water reaches the boiling point, how long will it take to boil away all the water?

When a space capsule returns to earth, its surfaces get very hot as it passes through the atmosphere at high speed. Has the space capsule been heated? If so, what was the source of the heat? If not, why is it hot?

Do (a) temperature, (b) heat, and (c) thermal energy describe a property of a system, an interaction of the system with its environment, or both? Explain

Two containers hold equal masses of nitrogen gas at equal temperatures. You supply 10 J of heat to container A while not allowing its volume to change, and you supply 10 J of heat to container B while not allowing its pressure to change. Afterward, is temperature TA greater than, less than, or equal to TB? Explain.

You need to raise the temperature of a gas by 10C. To use the least amount of heat energy, should you heat the gas at constant pressure or at constant volume? Explain

Why is the molar specific heat of a gas at constant pressure larger than the molar specific heat at constant volume?

Figure Q19.6 shows an adiabatic process. a. Is the final temperature higher than, lower than, or equal to the initial temperature? b. Is any heat energy added to or removed from the system in this process? Explain

Figure Q19.7 shows two different processes taking an ideal gas from state i to state f. Is the work done on the gas in process A greater than, less than, or equal to the work done in process B? Explain

Figure Q19.8 shows two different processes taking an ideal gas from state i to state f. a. Is the temperature change T during process A larger than, smaller than, or equal to the change during process B? Explain. b. Is the heat energy added during process A greater than, less than, or equal to the heat added during process B? Explain.

The gas cylinder in Figure Q19.9 is a rigid container that is well insulated except for the bottom surface, which is in contact with a block of ice. The initial gas temperature is 7 0C. a. During the process that occurs until the gas reaches a new equilibrium, are (i) T, (ii) W, and (iii) Q greater than, less than, or equal to zero? Explain. b. Draw a pV diagram showing the process.

The gas cylinder in Figure Q19.10 is well insulated except for the bottom surface, which is in contact with a block of ice. The piston can slide without friction. The initial gas temperature is 7 0C. a. During the process that occurs until the gas reaches a new equilibrium, are (i) T, (ii) W, and (iii) Q greater than, less than, or equal to zero? Explain. b. Draw a pV diagram showing the process

The gas cylinder in Figure Q19.11 is well insulated on all sides. The piston can slide without friction. Many small masses on top of the piston are removed one by one until the total mass is reduced by 50%. a. During this process, are (i) T, (ii) W, and (iii) Q greater than, less than, or equal to zero? Explain. b. Draw a pV diagram showing the process

How much work is done on the gas in the process shown in Figure EX19.1?

How much work is done on the gas in the process shown in Figure EX19.2?

80 J of work are done on the gas in the process shown in Figure EX19.3. What is V1 in cm3 ?

A 2000 cm3 container holds 0.10 mol of helium gas at 300C. How much work must be done to compress the gas to 1000 cm3 at (a) constant pressure and (b) constant temperature?

500 J of work must be done to compress a gas to half its initial volume at constant temperature. How much work must be done to compress the gas by a factor of 10, starting from its initial volume?

Draw a first-law bar chart (see Figure 19.12) for the gas process in Figure EX19.6.

Draw a first-law bar chart (see Figure 19.12) for the gas process in Figure EX19.7.

Draw a first-law bar chart (see Figure 19.12) for the gas process in Figure EX19.8.

Draw a first-law bar chart (see Figure 19.12) for the gas process in Figure EX19.9

A gas is compressed from 600 cm3 to 200 cm3 at a constant pressure of 400 kPa. At the same time, 100 J of heat energy is transferred out of the gas. What is the change in thermal energy of the gas during this process?

500 J of work are done on a system in a process that decreases the systems thermal energy by 200 J. How much heat energy is transferred to or from the system?

How much heat energy must be added to a 6.0-cm-diameter copper sphere to raise its temperature from -50C to 150C?

A rapidly spinning paddle wheel raises the temperature of 200 mL of water from 21C to 25C. How much (a) heat is transferred and (b) work is done in this process?

a. 100 J of heat energy are transferred to 20 g of mercury. By how much does the temperature increase? b. How much heat is needed to raise the temperature of 20 g of water by the same amount?

How much heat is needed to change 20 g of mercury at 20C into mercury vapor at the boiling point?

What is the maximum mass of ethyl alcohol you could boil with 1000 J of heat, starting from 20C?

One way you keep from overheating is by perspiring. Evaporationa phase changerequires heat, and the heat energy is removed from your body. Evaporation is much like boiling, only waters heat of vaporization at 35C is a somewhat larger 24 * 105 J/kg because at lower temperatures more energy is required to break the molecular bonds. Very strenuous activity can cause an adult human to produce 30 g of perspiration per minute. If all the perspiration evaporates, rather than dripping off, at what rate (in J/s) is it possible to exhaust heat by perspiring?

A scientist whose scale is broken but who has a working 2.5 kW heating coil and a thermometer decides to improvise to determine the mass of a block of aluminum she has recently acquired. She heats the aluminum for 30 s and finds that its temperature increases from 20C to 35C. What is the mass of the aluminum?

Two cars collide head-on while each is traveling at 80 km/h. Suppose all their kinetic energy is transformed into the thermal energy of the wrecks. What is the temperature increase of each car? You can assume that each cars specific heat is that of iron.

An experiment measures the temperature of a 500 g substance while steadily supplying heat to it. Figure EX19.20 shows the results of the experiment. What are the (a) specific heat of the solid phase, (b) specific heat of the liquid phase, (c) melting and boiling temperatures, and (d) heats of fusion and vaporization?

30 g of copper pellets are removed from a 300C oven and immediately dropped into 100 mL of water at 20C in an insulated cup. What will the new water temperature be?

A 750 g aluminum pan is removed from the stove and plunged into a sink filled with 10.0 L of water at 20.0C. The water temperature quickly rises to 24.0C. What was the initial temperature of the pan in C and in F?

A 50.0 g thermometer is used to measure the temperature of 200 mL of water. The specific heat of the thermometer, which is mostly glass, is 750 J/kgK, and it reads 20.0C while lying on the table. After being completely immersed in the water, the thermometers reading stabilizes at 71.2C. What was the actual water temperature before it was measured?

A 500 g metal sphere is heated to 300C, then dropped into a beaker containing 300 cm3 of mercury at 20.0C. A short time later the mercury temperature stabilizes at 99.0C. Identify the metal.

A 65 cm3 block of iron is removed from an 800C furnace and immediately dropped into 200 mL of 20C water. What fraction of the water boils away?

A container holds 1.0 g of argon at a pressure of 8.0 atm. a. How much heat is required to increase the temperature by 100C at constant volume? b. How much will the temperature increase if this amount of heat energy is transferred to the gas at constant pressure?

A container holds 1.0 g of oxygen at a pressure of 8.0 atm. a. How much heat is required to increase the temperature by 100C at constant pressure? b. How much will the temperature increase if this amount of heat energy is transferred to the gas at constant volume?

The volume of a gas is halved during an adiabatic compression that increases the pressure by a factor of 2.5. a. What is the specific heat ratio g? b. By what factor does the temperature increase?

A gas cylinder holds 0.10 mol of O2 at 150C and a pressure of 3.0 atm. The gas expands adiabatically until the pressure is halved. What are the final (a) volume and (b) temperature?

A gas cylinder holds 0.10 mol of O2 at 150C and a pressure of 3.0 atm. The gas expands adiabatically until the volume is doubled. What are the final (a) pressure and (b) temperature?

0.10 mol of nitrogen gas follow the two processes shown in Figure EX19.31. How much heat is required for each?

A monatomic gas follows the process 1 S 2 S 3 shown in Figure EX19.32. How much heat is needed for (a) process 1 S 2 and (b) process 2 S 3?

The ends of a 20-cm-long, 2.0-cm-diameter rod are maintained at 0C and 100C by immersion in an ice-water bath and boiling water. Heat is conducted through the rod at 4.5 * 104 J per hour. Of what material is the rod made?

A 10 m * 14 m house is built on a 12-cm-thick concrete slab. What is the heat-loss rate through the slab if the ground temperature is 5C while the interior of the house is 22C?

You are boiling pasta and absentmindedly grab a copper stirring spoon rather than your wooden spoon. The copper spoon has a 20 mm * 1.5 mm rectangular cross section, and the distance from the boiling water to your 35C hand is 18 cm. How long does it take the spoon to transfer 25 J of energy to your hand?

What maximum power can be radiated by a 10-cm-diameter solid lead sphere? Assume an emissivity of 1.

Radiation from the head is a major source of heat loss from the human body. Model a head as a 20-cm-diameter, 20-cm-tall cylinder with a flat top. If the bodys surface temperature is 35C, what is the net rate of heat loss on a chilly 5C day? All skin, regardless of color, is effectively black in the infrared where the radiation occurs, so use an emissivity of 0.95.

A 5.0 g ice cube at -20C is in a rigid, sealed container from which all the air has been evacuated. How much heat is required to change this ice cube into steam at 200C? Steam has CV = 1500 J/kgK and CP = 1960 J/kgK.

A 5.0-m-diameter garden pond is 30 cm deep. Solar energy is incident on the pond at an average rate of 400 W/m2 . If the water absorbs all the solar energy and does not exchange energy with its surroundings, how many hours will it take to warm from 15C to 25C?

The burner on an electric stove has a power output of 2.0 kW. A 750 g stainless steel teakettle is filled with 20C water and placed on the already hot burner. If it takes 3.0 min for the water to reach a boil, what volume of water, in cm3 , was in the kettle? Stainless steel is mostly iron, so you can assume its specific heat is that of iron

When air is inhaled, it quickly becomes saturated with water vapor as it passes through the moist airways. Consequently, an adult human exhales about 25 mg of evaporated water with each breath. Evaporationa phase changerequires heat, and the heat energy is removed from your body. Evaporation is much like boiling, only waters heat of vaporization at 35C is a somewhat larger 24 * 105 J/kg because at lower temperatures more energy is required to break the molecular bonds. At 12 breaths/min, on a dry day when the inhaled air has almost no water content, what is the bodys rate of energy loss (in J/s) due to exhaled water? (For comparison, the energy loss from radiation, usually the largest loss on a cool day, is about 100 J/s.)

512 g of an unknown metal at a temperature of 15C is dropped into a 100 g aluminum container holding 325 g of water at 98C. A short time later, the container of water and metal stabilizes at a new temperature of 78C. Identify the metal.

A 150 L 140 gal2 electric hot-water tank has a 5.0 kW heater. How many minutes will it take to raise the water temperature from 65F to 140F?

The specific heat of most solids is nearly constant over a wide temperature range. Not so for diamond. Between 200 K and 600 K, the specific heat of diamond is reasonably well described by c = 2.8T - 350 J/kgK, where T is in K. For gemstone diamonds, 1 carat = 200 mg. How much heat energy is needed to raise the temperature of a 3.5 carat diamond from -50C to 250C?

A lava flow is threatening to engulf a small town. A 400-m-wide, 35-cm-thick tongue of 1200C lava is advancing at the rate of 1.0 m per minute. The mayor devises a plan to stop the lava in its tracks by flying in large quantities of 20C water and dousing it. The lava has density 2500 kg/m3 , specific heat 1100 J/kgK, melting temperature 800C, and heat of fusion 4.0 * 105 J/kg. How many liters of water per minute, at a minimum, will be needed to save the town?

Suppose you take and hold a deep breath on a chilly day, inhaling 3.0 L of air at 0C and 1 atm. a. How much heat must your body supply to warm the air to your internal body temperature of 37C? b. By how much does the airs volume increase as it warms?

Your 300 mL cup of coffee is too hot to drink when served at 90C. What is the mass of an ice cube, taken from a -20C freezer, that will cool your coffee to a pleasant 60C?

A typical nuclear reactor generates 1000 MW (1000 MJ/s) of electrical energy. In doing so, it produces 2000 MW of waste heat that must be removed from the reactor to keep it from melting down. Many reactors are sited next to large bodies of water so that they can use the water for cooling. Consider a reactor where the intake water is at 18C. State regulations limit the temperature of the output water to 30C so as not to harm aquatic organisms. How many liters of cooling water have to be pumped through the reactor each minute?

2.0 mol of gas are at 30C and a pressure of 1.5 atm. How much work must be done on the gas to compress it to one third of its initial volume at (a) constant temperature and (b) constant pressure? (c) Show both processes on a single pV diagram.

A 6.0-cm-diameter cylinder of nitrogen gas has a 4.0-cm-thick movable copper piston. The cylinder is oriented vertically, as shown in Figure P19.50, and the air above the piston is evacuated. When the gas temperature is 20C, the piston floats 20 cm above the bottom of the cylinder. a. What is the gas pressure? b. How many gas molecules are in the cylinder? Then 2.0 J of heat energy are transferred to the gas. c. What is the new equilibrium temperature of the gas? d. What is the final height of the piston? e. How much work is done on the gas as the piston rises?

A 560 kg concrete table needs to be supported at the four corners by compressed-air cylinders. Each cylinder is 25 cm in diameter and has a 1.20 m initial length when the pressure inside is 1.0 atm. A hoist lowers the table very slowly, compressing the cylinders while allowing them to stay in thermal equilibrium with their surroundings. How much work has been done on the gas of the four cylinders when the table reaches its equilibrium position?

An ideal-gas process is described by p = cV1/2 , where c is a constant. a. Find an expression for the work done on the gas in this process as the volume changes from V1 to V2. b. 0.033 mol of gas at an initial temperature of 150C is compressed, using this process, from 300 cm3 to 200 cm3 . How much work is done on the gas? c. What is the final temperature of the gas in C?

A 10-cm-diameter cylinder contains argon gas at 10 atm pressure and a temperature of 50C. A piston can slide in and out of the cylinder. The cylinders initial length is 20 cm. 2500 J of heat are transferred to the gas, causing the gas to expand at constant pressure. What are (a) the final temperature and (b) the final length of the cylinder?

A cube 20 cm on each side contains 3.0 g of helium at 20C. 1000 J of heat energy are transferred to this gas. What are (a) the final pressure if the process is at constant volume and (b) the final volume if the process is at constant pressure? (c) Show and label both processes on a single pV diagram

An 8.0-cm-diameter, well-insulated vertical cylinder containing nitrogen gas is sealed at the top by a 5.1 kg frictionless piston. The air pressure above the piston is 100 kPa. a. What is the gas pressure inside the cylinder? b. Initially, the piston height above the bottom of the cylinder is 26 cm. What will be the piston height if an additional 3.5 kg are placed on top of the piston?

n moles of an ideal gas at temperature T1 and volume V1 expand isothermally until the volume has doubled. In terms of n, T1, and V1, what are (a) the final temperature, (b) the work done on the gas, and (c) the heat energy transferred to the gas?

5.0 g of nitrogen gas at 20C and an initial pressure of 3.0 atm undergo an isobaric expansion until the volume has tripled. a. What are the gas volume and temperature after the expansion? b. How much heat energy is transferred to the gas to cause this expansion? The gas pressure is then decreased at constant volume until the original temperature is reached. c. What is the gas pressure after the decrease? d. What amount of heat energy is transferred from the gas as its pressure decreases? e. Show the total process on a pV diagram. Provide an appropriate scale on both axes

0.10 mol of nitrogen gas follow the two processes shown in Figure P19.58. How much heat is required for each?

You come into lab one day and find a well-insulated 2000 mL thermos bottle containing 500 mL of boiling liquid nitrogen. The remainder of the thermos has nitrogen gas at a pressure of 1.0 atm. The gas and liquid are in thermal equilibrium. While waiting for lab to start, you notice a piece of iron on the table with 197 g written on it. Just for fun, you drop the iron into the thermos and seal the cap tightly so that no gas can escape. After a few seconds have passed, what is the pressure inside the thermos? The density of liquid nitrogen is 810 kg/m

Your laboratory assignment for the week is to measure the specific heat ratio g of carbon dioxide. The gas is contained in a cylinder with a movable piston and a thermometer. When the piston is withdrawn as far as possible, the cylinders length is 20 cm. You decide to push the piston in very rapidly by various amounts and, for each push, to measure the temperature of the carbon dioxide. Before each push, you withdraw the piston all the way and wait several minutes for the gas to come to the room temperature of 21C. Your data are as follows: Push (cm) Temperature (C) 5 35 10 68 13 110 15 150 Use the best-fit line of an appropriate graph to determine g for carbon dioxide

Two cylinders each contain 0.10 mol of a diatomic gas at 300 K and a pressure of 3.0 atm. Cylinder A expands isothermally and cylinder B expands adiabatically until the pressure of each is 1.0 atm. a. What are the final temperature and volume of each? b. Show both processes on a single pV diagram. Use an appropriate scale on both axes.

Figure P19.62 shows a thermodynamic process followed by 120 mg of helium. a. Determine the pressure (in atm), temperature (in C), and volume (in cm3 ) of the gas at points 1, 2, and 3. Put your results in a table for easy reading. b. How much work is done on the gas during each of the three segments? c. How much heat energy is transferred to or from the gas during each of the three segments?

Two containers of a diatomic gas have the same initial conditions. One container, heated at constant pressure, has a temperature increase of 20C. The other container receives the same quantity of heat energy, but at constant volume. What is its temperature increase?

14 g of nitrogen gas at STP are adiabatically compressed to a pressure of 20 atm. What are (a) the final temperature, (b) the work done on the gas, (c) the heat transfer to the gas, and (d) the compression ratio Vmax/Vmin ? (e) Show the process on a pV diagram, using proper scales on both axes.

14 g of nitrogen gas at STP are pressurized in an isochoric process to a pressure of 20 atm. What are (a) the final temperature, (b) the work done on the gas, (c) the heat transfer to the gas, and (d) the pressure ratio pmax/pmin ? (e) Show the process on a pV diagram, using proper scales on both axes

A cylinder with a movable piston contains n moles of gas at a temperature higher than that of the surrounding environment. An external force on the piston keeps the pressure constant while the gas cools as T = 1T20e-t/t , where T is the temperature difference between the gas and the environment, 1T20 is the initial temperature difference, and t is the time constant. a. Find an expression for the rate at which the environment does work on the gas. Recall that the rate of doing work is power. b. What power is initially supplied by the environment if 0.15 mol of gas are initially 12C warmer than the surroundings and cool with a time constant of 60 s?

When strong winds rapidly carry air down from mountains to a lower elevation, the air has no time to exchange heat with its surroundings. The air is compressed as the pressure rises, and its temperature can increase dramatically. These warm winds are called Chinook winds in the Rocky Mountains and Santa Ana winds in California. Suppose the air temperature high in the mountains behind Los Angeles is 0C at an elevation where the air pressure is 60 kPa. What will the air temperature be, in C and F, when the Santa Ana winds have carried this air down to an elevation near sea level where the air pressure is 100 kPa?

You would like to put a solar hot water system on your roof, but youre not sure its feasible. A reference book on solar energy shows that the ground-level solar intensity in your city is 800 W/m2 for at least 5 hours a day throughout most of the year. Assuming that a completely black collector plate loses energy only by radiation, and that the air temperature is 20C, what is the equilibrium temperature of a collector plate directly facing the sun? Note that while a plate has two sides, only the side facing the sun will radiate because the opposite side will be well insulated.

A cubical box 20 cm on a side is constructed from 1.2-cmthick concrete panels. A 100 W lightbulb is sealed inside the box. What is the air temperature inside the box when the light is on if the surrounding air temperature is 20C?

A cylindrical copper rod and an iron rod with exactly the same dimensions are welded together end to end. The outside end of the copper rod is held at 100C, and the outside end of the iron rod is held at 0C. What is the temperature at the midpoint where the rods are joined together?

Most stars are main-sequence stars, a group of stars for which size, mass, surface temperature, and radiated power are closely related. The sun, for instance, is a yellow main-sequence star with a surface temperature of 5800 K. For a main-sequence star whose mass M is more than twice that of the sun, the total radiated power, relative to the sun, is approximately P/Psun = 1.51M/Msun23.5 . The star Regulus A is a bluish main-sequence star with mass 3.8Msun and radius 3.1Rsun. What is the surface temperature of Regulus A?

A satellite to reflect radar is a 2.0-m-diameter, 2.0-mm-thick spherical copper shell. While orbiting the earth, the satellite absorbs sunlight and is warmed to 50C. When it passes into the earths shadow, the satellite radiates energy to deep space. The temperature of deep space is actually 3 K, as a result of the Big Bang 14 billion years ago, but it is so much colder than the satellite that you can assume a deep-space temperature of 0 K. If the satellites emissivity is 0.75, to what temperature, in C, will it drop during the 45 minutes it takes to move through the earths shadow?

The suns intensity at the distance of the earth is 1370 W/m2 . 30% of this energy is reflected by water and clouds; 70% is absorbed. What would be the earths average temperature (in C) if the earth had no atmosphere? The emissivity of the surface is very close to 1. (The actual average temperature of the earth, about 15C, is higher than your calculation because of the greenhouse effect.)

In Problems 74 through 76 you are given the equation used to solve a problem. For each of these, you are to a. Write a realistic problem for which this is the correct equation. b. Finish the solution of the problem.50 J = -n18.31 J/mol K21350 K2ln1 1 3 2

In Problems 74 through 76 you are given the equation used to solve a problem. For each of these, you are to a. Write a realistic problem for which this is the correct equation. b. Finish the solution of the problem.1200 * 10-6 m3 2113,600 kg/m3 2 * 1140 J/kg K2190C - 15C2 + 10.50 kg21449 J/kg K2190C - Ti 2 = 0

In Problems 74 through 76 you are given the equation used to solve a problem. For each of these, you are to a. Write a realistic problem for which this is the correct equation. b. Finish the solution of the problem.110 atm2V2 1.40 = 11.0 atm2V1 1.40

10 g of aluminum at 200C and 20 g of copper are dropped into 50 cm3 of ethyl alcohol at 15C. The temperature quickly comes to 25C. What was the initial temperature of the copper?

A beaker with a metal bottom is filled with 20 g of water at 20C. It is brought into good thermal contact with a 4000 cm3 container holding 0.40 mol of a monatomic gas at 10 atm pressure. Both containers are well insulated from their surroundings.What is the gas pressure after a long time has elapsed? You can assume that the containers themselves are nearly massless and do not affect the outcome.

Figure CP19.79 shows a thermodynamic process followed by 0.015 mol of hydrogen. How much heat energy is transferred to the gas?

One cylinder in the diesel engine of a truck has an initial volume of 600 cm3 . Air is admitted to the cylinder at 30C and a pressure of 1.0 atm. The piston rod then does 400 J of work to rapidly compress the air. What are its final temperature and volume?

0.020 mol of a diatomic gas, with initial temperature 20C, are compressed from 1500 cm3 to 500 cm3 in a process in which pV2 = constant. How much heat energy is added during this process?

A monatomic gas fills the left end of the cylinder in Figure CP19.82. At 300 K, the gas cylinder length is 10.0 cm and the spring is compressed by 2.0 cm. How much heat energy must be added to the gas to expand the cylinder length to 16.0 cm?