(d) Ideal gas molecules

Gas laws:

• Gas molecules have rapid and random motion.
• When they hit the walls of the container, they exert a force.
• Pressure = Force/Area

Absolute zero:

• At absolute zero the particles have no thermal energy or kinetic energy, so they cannot exert a force.
• Absolute zero = 0 Kelvin = -273⁰C

0 K = -273 ⁰C

E.g.         100K = -173⁰C

                200⁰C = 473K

As you increase the temperature of a gas, the kinetic energy of the gas particles increases and thus their average speed also increases.

The Kelvin temperature of a gas is proportional to the average kinetic energy of its molecules.

• As you heat the gas, the kinetic energy of the particles increases, and thus so does their average speed.
• This means more collisions per second with the walls, and they exert a larger force on the wall.
• This causes in the total pressure being exerted by the particles to rise.
• If temperature is constant, the average speed of the particles is constant.
• If the same number of particles is placed in a container of smaller volume they will hit the walls of the container more often.
• More collisions per second means that the particles are exerting a larger force on the wall over the same time, so average force exerted on the walls has increased.