A diesel engine performs $2200$ J of mechanical work and discards $4300$ J of heat each cycle. How much heat must be supplied to the engine in each cycle?

Calculate the theoretical efficiency for an Otto-cycle engine with $g=1.40$ and $r=9.50$.

The Otto-cycle engine in a Mercedes-Benz SLK230 has a compression ratio of $8.8$. What is the ideal efficiency of the engine? Use $g=1.40$.

The coefficient of performance $K=H/P$ is a dimensionless quantity. Its value is independent of the units used for $H$ and $P$, as long as the same units, such as watts, are used for both quantities. However, it is common practice to express $H$ in Btu/h and $P$ in watts. When these mixed units are used, the ratio $H/P$ is called the energy efficiency ratio ($EER$). If a room air conditioner has $K=3.0$, what is its $EER$?

A refrigerator has a coefficient of performance of $2.25$, runs on an input of $135$ W of electrical power, and keeps its inside compartment at $5$°C. If you put a dozen $1.0$-L plastic bottles of water at $31$°C into this refrigerator, how long will it take for them to be cooled down to $5$°C? (Ignore any heat that leaves the plastic.)

A Carnot engine is operated between two heat reservoirs at temperatures of $520$ K and $300$ K. If the engine receives $6.45$ kJ of heat energy from the reservoir at $520$ K in each cycle, how many joules per cycle does it discard to the reservoir at $300$ K?

A Carnot engine is operated between two heat reservoirs at temperatures of $520$ K and $300$ K. How much mechanical work is performed by the engine during each cycle?

A Carnot engine is operated between two heat reservoirs at temperatures of $520$ K and $300$ K. What is the thermal efficiency of the engine?

A certain brand of freezer is advertised to use $730$ kWh of energy per year. Assuming the freezer operates for $5$ hours each day, how much power does it require while operating?

A certain brand of freezer is advertised to use $730$ kWh of energy per year. What is the theoretical maximum amount of ice this freezer could make in an hour, starting with water at $20.0$°C?

A Carnot refrigerator is operated between two heat reservoirs at temperatures of $320$ K and $270$ K. If in each cycle the refrigerator receives $415$ J of heat energy from the reservoir at $270$ K, how many joules of heat energy does it deliver to the reservoir at $320$ K?

A Carnot refrigerator is operated between two heat reservoirs at temperatures of $320$ K and $270$ K. If the refrigerator completes $165$ cycles each minute, what power input is required to operate it?

A Carnot refrigerator is operated between two heat reservoirs at temperatures of $320$ K and $270$ K. What is the coefficient of performance of the refrigerator?

A Carnot heat engine uses a hot reservoir consisting of a large amount of boiling water and a cold reservoir consisting of a large tub of ice and water. In $5$ minutes of operation, the heat rejected by the engine melts $0.0400$ kg of ice. During this time, how much work $W$ is performed by the engine?

A $4.50$-kg block of ice at $0.00$°C falls into the ocean and melts. The average temperature of the ocean is $3.50$°C, including all the deep water. By how much does the change of this ice to water at $3.50$°C alter the entropy of the world? Does the entropy increase or decrease? (Hint: Do you think that the ocean temperature will change appreciably as the ice melts?)

A sophomore with nothing better to do adds heat to $0.350$ kg of ice at $0.0$°C until it is all melted. What is the change in entropy of the water?

You decide to take a nice hot bath but discover that your thoughtless roommate has used up most of the hot water. You fill the tub with $195$ kg of $30.0$°C water and attempt to warm it further by pouring in $5.00$ kg of boiling water from the stove. Is this a reversible or an irreversible process? Use physical reasoning to explain.

A $15.0$-kg block of ice at $0.0$°C melts to liquid water at $0.0$°C inside a large room at $20.0$°C. Treat the ice and the room as an isolated system, and assume that the room is large enough for its temperature change to be ignored. Is the melting of the ice reversible or irreversible? Explain, using simple physical reasoning without resorting to any equations.

You make tea with $0.250$ kg of $85.0$°C water and let it cool to room temperature ($20.0$°C). Calculate the entropy change of the water while it cools.

Two moles of an ideal gas occupy a volume $V$. The gas expands isothermally and reversibly to a volume $3V$. Is the velocity distribution changed by the isothermal expansion? Explain.

A box is separated by a partition into two parts of equal volume. The left side of the box contains $500$ molecules of nitrogen gas; the right side contains $100$ molecules of oxygen gas. The two gases are at the same temperature. The partition is punctured, and equilibrium is eventually attained. Assume that the volume of the box is large enough for each gas to undergo a free expansion and not change temperature. On average, how many molecules of each type will there be in either half of the box?

A lonely party balloon with a volume of $2.40$ L and containing $0.100$ mol of air is left behind to drift in the temporarily uninhabited and depressurized International Space Station. Sunlight coming through a porthole heats and explodes the balloon, causing the air in it to undergo a free expansion into the empty station, whose total volume is $425$ m³. Calculate the entropy change of the air during the expansion.