Exam 15: Thermodynamics

A gasoline engine with an efficiency of 0.40 generates 1800 W of power. If a liter of gasoline has an energy content of 3.7 × 10⁷ J, how many liters of gasoline does the engine consume each hour?

What is the maximum possible efficiency of an engine operating between the boiling and freezing points of water at sea level?

A match ignites within in an oxygen-filled cylinder that has a movable piston. The piston is moved so quickly that no heat escapes. What kind of change is demonstrated in this process?

Heat is added to a sample of an ideal monatomic gas. Which one of the following statements is necessarily true?

An ideal monatomic gas expands isothermally from state A to state B. The gas then cools at constant volume to state C. The gas is then compressed isobarically to D before it is heated until it returns to state A. -How much work is done on the gas as it is compressed isobarically from state C to state D?

A container holding 1.2 kg of water at 20.0 °C is placed in a freezer that is kept at -20.0 °C. The water freezes and comes into thermal equilibrium with the interior of the freezer. -Which one of the following statements is true concerning this process?

Two moles of an ideal gas have an initial Kelvin temperature Ti and absolute pressure Pi. The gas undergoes a reversible isothermal compression from an initial volume Vi to a final volume 0.5Vi. -What is the change in entropy of the sample?

What change in temperature occurs when 1600 J of heat are removed from 3.0 moles of monatomic gas under constant pressure?

5.00 kg of liquid water is heated to 100.0 °C in a closed system. At this temperature, the density of liquid water is 958 kg/m³. The pressure is maintained at atmospheric pressure of 1.01 × 10⁵ Pa. A moveable piston of negligible weight rests on the surface of the water. The water is then converted to steam by adding an additional amount of heat to the system. When all of the water is converted, the final volume of the steam is 8.50 m³. The latent heat of vaporization of water is 2.26 × 10⁶ J/kg. -How much heat is added to the system in the isothermal process of converting all of the water into steam?

Which one of the following situations is a direct application of the Zeroth Law of Thermodynamics?

An ideal monatomic gas expands isobarically from state A to state B. It is then compressed isothermally from state B to state C and finally cooled at constant volume until it returns to its initial state A. -What is the temperature of the gas when it is in state B?

In a reversible heat engine, one mole of an ideal gas is carried through a circular cycle beginning and ending at point A as shown in the figure. Which one of the following statements concerning this system is false?

Two moles of an ideal gas have an initial Kelvin temperature Ti and absolute pressure Pi. The gas undergoes a reversible isothermal compression from an initial volume Vi to a final volume 0.5Vi. -Which one of the following expressions represents the final pressure of the gas?

A thermally isolated sample of an ideal gas at a fixed temperature is confined to one half of a container by an impermeable membrane. The other half of the container is evacuated. The membrane is then pierced and the gas is allowed to expand freely and to double its volume as shown. Which one of the following statements is true concerning this situation?

A Carnot engine operates between hot and cold reservoirs with temperatures 527 °C and -73.0 °C, respectively. If the engine performs 1000.0 J of work per cycle, how much heat is extracted per cycle from the hot reservoir?

Enclosed beneath the moveable piston in the drawing is 4.8 moles of a monatomic ideal gas. The gas performs work on the piston as 2300 J of heat are added from the surroundings. During the process, the temperature of the gas decreases by 45 K. How much work does the gas perform?

A quantity of carbon monoxide gas is slowly compressed adiabatically in an insulated container to one-half of its initial volume. The ratio of the specific heat capacities at constant pressure and constant volume, c_P/c_V , for carbon dioxide is approximately 1.3. Determine the final pressure of the gas if the initial pressure is 2.0 × 10⁵ Pa.

An ideal monatomic gas expands isobarically from state A to state B. It is then compressed isothermally from state B to state C and finally cooled at constant volume until it returns to its initial state A. -How much work is done by the gas in expanding isobarically from A to B?

Which one of the following statements best describes the operation of a heat engine?

A container is divided into two chambers that are separated by a valve. The left chamber contains one mole of a monatomic ideal gas. The right chamber is evacuated. At some instant, the valve is opened and the gas rushes freely into the right chamber. Which one of the following statements concerning this process is true?