simple kinetic model of matter

A cup contains hot liquid. Some of the liquid evaporates. What happens to the mass and what happens to the weight of the liquid in the cup?

• A

• B

• C

• D

Which statement about evaporation is correct?

• Evaporation causes the temperature of the remaining liquid to decrease.

• Evaporation does not occur from a cold liquid near its freezing point.

• Evaporation does not occur from a dense liquid, such as mercury.

• Evaporation occurs from all parts of a liquid.

A gas is stored in a sealed container of constant volume. The temperature of the gas increases. This causes the pressure of the gas to increase. What happens to the gas molecules during this pressure increase?

• The average kinetic energy of the molecules increases.

• The average separation of the molecules decreases.

• The average separation of the molecules increases.

• The volume of each molecule increases.

A liquid is evaporating. The liquid is not boiling. Which statement about the liquid is correct?

• Any molecule can escape, and from any part of the liquid.

• Any molecule can escape, but only from the liquid surface.

• Only molecules with enough energy can escape, and only from the liquid surface.

• Only molecules with enough energy can escape, but from any part of the liquid.

• A

• B

• C

• D

What causes the random, zig-zag movement (Brownian motion) of smoke particles suspended in air?

• air molecules colliding with smoke particles

• convection currents as the hot smoke rises

• smoke particles colliding with each other

• smoke particles reacting with oxygen molecules in the air

• A

• B

• C

• D

• The pressure of the air decreases because its molecules now travel more slowly.

• The pressure of the air decreases because the area of the syringe walls is now smaller.

• The pressure of the air increases because its molecules now hit the syringe walls more frequently.

• The pressure of the air increases because its molecules now travel more quickly.

• pollen grains being hit by other pollen grains

• pollen grains being hit by water molecules

• water molecules being hit by other water molecules

• water molecules being hit by pollen grains

• A

• B

• C

• D