### Short Answer

#### 12.1 Zeroth Law of Thermodynamics: Thermal Equilibrium

What does *green* energy development entail?

- Green energy involves finding new ways to harness clean and renewable alternative energy sources.
- Green energy involves finding new ways to conserve alternative energy sources.
- Green energy involves decreasing the efficiency of nonrenewable energy resources.
- Green energy involves finding new ways to harness nonrenewable energy resources.

Why are the sun and Earth not in thermal equilibrium?

- The mass of the sun is much greater than the mass of Earth.
- There is a vast amount of empty space between the sun and Earth.
- The diameter of the sun is much greater than the diameter of Earth.
- The sun is in thermal contact with Earth.

#### 12.2 First law of Thermodynamics: Thermal Energy and Work

If a fixed quantity of an ideal gas is held at a constant volume, which variable relates to pressure, and what is that relation?

- Temperature; inverse proportionality $\left(P\phantom{\rule{0.25em}{0ex}}\propto \text{}\frac{\text{1}}{T}\right)$
- Temperature, direct proportionality to square root $\left(P\phantom{\rule{0.25em}{0ex}}\propto \text{}\sqrt{T}\right)$
- Temperature; direct proportionality $\left(P\phantom{\rule{0.25em}{0ex}}\propto \text{}T\right)$
- Temperature; direct proportionality to square $\left(P\phantom{\rule{0.25em}{0ex}}\propto {\phantom{\rule{0.25em}{0ex}}T}^{\text{2}}\right)$

By convention, if *Q* is positive, what is the direction in which heat transfers energy with regard to the system?

- The direction of the heat transfer of energy depends on the changes in
*W*, regardless of the sign of*Q*. - The direction of
*Q*cannot be determined from just the sign of*Q*. - The direction of net heat transfer of energy will be out of the system.
- The direction of net heat transfer of energy will be into the system.

#### 12.3 Second Law of Thermodynamics: Entropy

Which sort of thermal energy do molecules in a solid possess?

- electric potential energy
- gravitational potential energy
- translational kinetic energy
- vibrational kinetic energy

What is the change in entropy caused by melting 5.00 kg of ice at 0 °C ?

- 0 J/K
- 6.11×10
^{3}J/K - 6.11×10
^{4}J/K - ∞J/K

#### 12.4 Applications of Thermodynamics: Heat Engines, Heat Pumps, and Refrigerators

Which component of an air conditioner converts gas into liquid?

- the condenser
- the compressor
- the evaporator
- the thermostat

What is one example for which calculating thermal efficiency is of interest?

- A wind turbine
- An electric pump
- A bicycle
- A car engine

How is the efficiency of a refrigerator or heat pump expressed?

- $Eff=W\sqrt{{Q}_{\text{c}}}$
- $Eff=\frac{W}{{Q}_{\text{c}}}$
- $Eff={Q}_{\text{c}}\times W$
- $Eff=\frac{{Q}_{\text{c}}}{W}$