Questions: Gas Behavior: Pressure, Volume, and Temperature

Question 1

What happens to the pressure of a gas in a sealed, rigid container when the temperature increases?

• A. Pressure decreases
• B. Pressure stays the same
• C. Pressure increases
• D. The gas escapes

Answer: (C)

In a sealed, rigid container (fixed volume), increasing the temperature makes gas particles move faster. Faster particles hit the container walls more often and with greater force, which increases the pressure. Since the container is rigid and sealed, the volume cannot change and no gas escapes.

Question 2

Compressing a gas into a smaller volume decreases its pressure.

• T. True
• F. False

Answer: False

Compressing a gas into a smaller volume increases its pressure. With the same number of particles squeezed into less space, the particles collide with the container walls more frequently, producing more force per unit area — which is higher pressure.

Question 3

Explain why a balloon shrinks when placed in a freezer.

Model answer: Cooling the gas inside the balloon makes the particles move slower. They hit the balloon walls less often and with less force, so the pressure inside decreases and the balloon shrinks as the outside air pressure pushes in.

A balloon is flexible, so its volume adjusts when the internal pressure changes. Cooling the gas lowers the kinetic energy of the particles, reducing the frequency and force of their collisions with the balloon walls. The internal pressure drops below the external atmospheric pressure, and the balloon contracts until the pressures balance again.