Question

1. an

amount of energy is required to melt 1 gram of ice at 0°c compared to what is required to freeze 1 gram of water at 0°c.
equal
smaller
larger
sometimes larger, sometimes smaller

1. which of these will raise the boiling point of a liquid?

a decrease in atmospheric pressure
an increase of thermal energy
addition of nonvolatile solutes
an air current above the surface of the liquid
12.
is a flammable liquid that is used in aerosol cans because of its high vapor pressure.
acetone
dimethyl ether
ethylene glycol
isobutane

1. which of these statements regarding vapor pressure is not true?

evaporation and condensation are constantly happening at a liquids surface.
vapor pressure is the amount of pressure needed to have evaporation and condensation occurring at the same rate.
at higher temperatures, condensation occurs more quickly than evaporation.
when the air is dry, evaporation occurs more quickly than condensation.

1. in the

of a heat pump, the refrigerant is heated by increasing its pressure.
compressor
evaporator
condenser
expansion valve

1. substances can skip the liquid state and change from a solid directly into a gas by the process of

deposition
fusion
sublimation
vaporization

1. one liter of 65°c water is mixed with one liter of 25°c water. what temperature will the mixture be when it reaches thermal equilibrium?

20°c
35°c
45°c
90°c

1. the amount of heat needed to change an objects temperature by a specific amount is its

critical temperature
heat capacity
latent heat
specific heat

1. the transfer of heat by moving fluids is known as

conduction
convection
entropy
fusion

1. the heat absorbed or released when a substance undergoes a change of state is called

heat capacity
plasma
specific heat
latent heat

1. what is the specific heat of an object with a mass of 2.0 g and a heat capacity of 4.0 j/°c?

0.5 j/g·°c
2.0 j/g·°c
8.0 j/g·°c
6.0 j/g·°c

Explanation:

1. The heat of fusion is the same whether melting or freezing, so equal energy is involved for the same mass at the same temperature.
2. Adding non - volatile solutes raises the boiling point of a liquid due to colligative properties.
3. Dimethyl ether is a flammable liquid used in aerosol cans because of its high vapor pressure.
4. At higher temperatures, evaporation occurs more quickly than condensation, not the other way around.
5. In the compressor of a heat pump, the refrigerant is heated by increasing its pressure.
6. Sublimation is the process by which substances change from a solid directly into a gas.
7. Using the principle of conservation of energy for heat transfer, the final temperature of the mixture of equal - volume (and thus equal - mass assuming same density) waters is the average of the initial temperatures, $\frac{65 + 25}{2}=45^{\circ}C$.
8. The amount of heat needed to change an object's temperature by a specific amount is its heat capacity.
9. The transfer of heat by moving fluids is called convection.
10. The heat absorbed or released when a substance undergoes a change of state is called latent heat.
11. Specific heat $c=\frac{C}{m}$, where $C$ is heat capacity and $m$ is mass. So $c = \frac{4.0\ J/^{\circ}C}{2.0\ g}=2.0\ J/g\cdot^{\circ}C$.

Answer:

1. equal
2. addition of nonvolatile solutes
3. Dimethyl ether
4. At higher temperatures, condensation occurs more quickly than evaporation.
5. compressor
6. sublimation
7. $45^{\circ}C$
8. heat capacity
9. convection
10. latent heat
11. $2.0\ J/g\cdot^{\circ}C$