An automobile engine with an efficiency $0.21$ dumps heat to the environment at the rate of $330 \mathrm{~kW}$. What's its mechanical power output, in W and in hp?

A $40 \%$ efficient heat engine does mechanical work at the rate of $400 \mathrm{~W}$. If it runs for an entire day, find the heat removed from the hot reservoir and the heat transferred to the cold reservoir.

A heat engine does $650 \mathrm{~J}$ of work and dumps $1270 \mathrm{~J}$ of heat to its cold reservoir. What's its efficiency?

Earth receives energy from the Sun at an average rate of about $240 \mathrm{~W} / \mathrm{m}^2$. Given Earth's average temperature of $15^{\circ} \mathrm{C}$, find the rate of entropy increase associated with this energy flow.

Find the entropy increase when $100 \mathrm{~g}$ of nitrogen boil at atmospheric pressure.

Using data from Chapter 13 , find the entropy increase in $1.5 \mathrm{~kg}$ of mercury when it melts at $-39^{\circ} \mathrm{C}$ and 1 atm pressure.

$150 \mathrm{~g}$ of water at $0^{\circ} \mathrm{C}$ are placed in a freezer at $-4^{\circ} \mathrm{C}$. Find the net entropy change after all the water has turned to ice but is still at $0^{\circ} \mathrm{C}$.

Find the net entropy change when a $50-\mathrm{g}$ ice cube initially at $0^{\circ} \mathrm{C}$ melts in (b) a $35^{\circ} \mathrm{C}$ room.

Find the net entropy change when a $50-\mathrm{g}$ ice cube initially at $0^{\circ} \mathrm{C}$ melts in (a) a $10^{\circ} \mathrm{C}$ room.

Find the entropy created when $100 \mathrm{~g}$ of ice melts at $0^{\circ} \mathrm{C}$. Compare with the entropy created when the same mass of water boils at $100^{\circ} \mathrm{C}$.

Find the entropy change when $75 \mathrm{~g}$ of steam condenses to water at $100^{\circ} \mathrm{C}$.

Find the entropy change when water at $25^{\circ} \mathrm{C}$ (b) loses $1000 \mathrm{~J}$ of heat. Assume there's enough water that its temperature change is negligible.

Find the entropy change when water at $25^{\circ} \mathrm{C}$ (a) absorbs $1000 \mathrm{~J}$ of heat. Assume there's enough water that its temperature change is negligible.

A high-performance gasoline engine has a compression ratio of $10: 1$, meaning that air entering the cylinders is compressed to one-tenth its volume as the piston rises. If air enters this engine's cylinders at $290 \mathrm{~K}$ and $1 \mathrm{~atm}$, find (b) the temperature of the air at full compression. Assume adiabatic compression.