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 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.

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 (a) the pressure.

Consider the three-step cycle described by the complete triangle in Figure P14.49. (b) Find the net work.

Consider the three-step cycle described by the complete triangle in Figure P14.49. (a) Is the net work done over the cycle positive or negative? Why?

Exercising vigorously, you do work on your surroundings, so $W<0$. You also transfer heat to your surroundings, so $Q<0$. With $W<0$ and $Q<0$, why doesn't your body temperature drop?

What happens to a gas's temperature when it (b) is compressed adiabatically?

What happens to a gas's temperature when it (a) expands adiabatically?