Gas Laws

The relationship between pressure p and volume V of a gas is given as PV = constant.

Under which conditions for the mass of a gas and its temperature does the equation hold?

• changing mass; changing temperature

• changing mass; constant temperature

• constant mass; changing temperature

• constant mass; constant temperature

 A gas is headted in a sealed container. The volume of the container does not change.

What happens to the molecules of the gas?

• The average distance between molecules increases.

• The average kinetic energy of the molecules increases.

• The mass of each molecule increases.

• The volume of each molecule increases.

A fixed mass of gas has a volume of 25 . The pressure of the gas is 100 kPa. The volume of the gas is slowly decreased by 15  at constant temperature.

What is the change in pressure of the gas?

• 67 kPa

• 150 kPa

• 170 kPa

• 250 kPa

A closed container of gas is heated. The pressure of the gas increases.

Which statement explains this increase in pressure?

• The changes in the momentum of the gas molecules striking the walls of the container increase.

• The forces of attraction between the gas molecules and the walls of the container increase.

• The gas molecules collide with each other more frequently.

• The gas molecules lose more energy when they strike the walls of the container.

A bubble of air of volume 3.0 mm³  is under water. The bubble is at a depth where the pressure of the air inside the bubble is four times atmospheric pressure.

The temperature of the air in the bubble stays the same as it rises to the surface.

What is the volume of the air in the bubble as it reaches the surface?

• 3.0 mm³

• 9.0 mm³

• 12 mm³

• 15 mm³

The diagram shows an air-filled rubber toy. A child sits on the toy and its volume decreases. The temperature of the air in the toy does not change.

How does the air pressure in the toy change and why?

• decreases because air molecules move more slowly.

• decreases because air molecules strike the rubber less frequently.

• increases because air molecules move more quickly.

• increases because air molecules strike the rubber more frequently.

The diagram shows a quantity of gas trapped in a cylinder. The piston is pushed in slowly and the gas is compressed. The temperature of the gas does not change.

Which graph shows the relationship between the pressure and the volume of the gas?

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Air is trapped inside a cylinder. The volume of the cylinder cannot change. The temperature of the air is increased.

Which of the graphs below shows the correct relationship between pressure and temperature?

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