Can you warm a kitchen in winter by leaving the oven door open? Can you cool the kitchen on a hot summer day by leaving the refrigerator door open? Explain.

The COPs are defined differently for heat pumps and air conditioners. Explain why.

A bag containing $0^{\circ} \mathrm{C}$ ice is much more effective in absorbing energy than one containing the same amount of $0^{\circ} \mathrm{C}$ water. $(a)$ How much heat transfer is necessary to raise the temperature of $0.800 \mathrm{~kg}$ of water from $0^{\circ} \mathrm{C}$ to $30.0^{\circ} \mathrm{C}$ ? $(b)$ How much heat transfer is required to first melt $0.800 \mathrm{~kg}$ of $0^{\circ} \mathrm{C}$ ice and then raise its temperature? $(c)$ Explain how your answer supports the contention that the ice is more effective.

Which statement best describes how a refrigerator works?
A. It uses energy to cause heat to flow from a colder location to a hotter location.
B. It does work by causing heat to flow from a hotter location to a colder location.
C. It cools through reverse osmosis.
D. It rejects heat from the environment into the enclosure.

If this heat pump operates on 1200 W of electrical power, what is the maximum heat it can deliver into your house each hour?

The print in many books averages 3.50 mm in height. How high is the image of the print on the retina when the book is held 30.0 cm from the eye?

A bag containing $0^{\circ} \mathrm{C}$ ice is much more effective in absorbing energy than one containing the same amount of $0^{\circ} \mathrm{C}$ water.

How much heat transfer is necessary to raise the temperature of 0.800 kg of water from $0^{\circ} \mathrm{C}$ to $30.0^{\circ} \mathrm{C}$ ?

Explain how water's entropy can decrease when it freezes without violating the second law of thermodynamics. Specifically, explain what happens to the entropy of its surroundings.

A food establishment has a history of cockroach infestations. What sign of cockroach infestation might food workers notice?
A. Dirt on the floor
B. A strong, oily smell
C. Rusty floor drain covers
D. Spoiled food in the refrigerator

Suppose you walk into a sauna that has an ambient temperature of $50.0^{\circ} \mathrm{C}$. Calculate the rate of heat transfer to you by radiation given your skin temperature is $37.0^{\circ} \mathrm{C}$, the emissivity of skin is 0.98 , and the surface area of your body is $1.50 \mathrm{~m}^2$.

Explain why heat pumps do not work as well in very cold climates as they do in milder ones. Is the same true of refrigerators?

One winter day, the climate control system of a large university classroom building malfunctions. As a result $500\ \mathrm{m}^{3}$ of excess cold air is brought in each minute. At what rate in kilowatts must heat transfer occur to warm this air by $10.0^{\circ} \mathrm{C}$ (that is, to bring the air to room temperature)?

Explain why the temperature of a gas increases when it is adiabatically compressed.

On a hot day, the temperature of an 80,000-L swimming pool increases by $1.50 ^ { \circ } \mathrm { C }$. What is the net heat transfer during this heating? Ignore any complications, such as loss of water by evaporation.