Particle Model and Pressure

• What is the motion of molecules in a gas?

  They are in constant random motion.
• What factor affects the average kinetic energy of gas molecules?

  The temperature of the substance.
• How does temperature affect the average kinetic energy of gas molecules?

  The higher the temperature, the higher the average kinetic energy.
• What effect does increasing temperature have on the pressure of a gas at constant volume?

  Pressure of the gas will increase.
• Why does pressure increase as temperature increases at constant volume?

  Kinetic energy of molecules increases.
• What happens to the rate of collisions in gas A (low pressure) compared to gas B (high pressure)?

  There are more collisions per second in gas B.
• Describe the force that the pressure of a gas exerts on the walls of its container.

  The net force acts at right-angles to the surface.
• How does increasing the volume of a gas result in a decrease of pressure?

  Molecules become more spread out, increasing time between collisions.
• What can be said about the product of pressure and volume for a fixed mass of gas at constant temperature?

  It is constant.
• What is the unit used for pressure?

  Pascal (Pa).
• What increases when you do work on a gas?

  The internal energy of the gas increases.
• Why does the temperature of air inside a bike pump increase when it is pumped?

  Work is done on a gas when compressed.
• How does doing work on a gas affect its average kinetic energy?

  It increases the average kinetic energy of the molecules.
• How does temperature relate to average kinetic energy in a gas?

  Temperature increases with an increase of average kinetic energy.