As the temperature of a gas increases, what happens to the particles of the gas?
An increase in total kinetic energy
An increase in the speed of individual particles
The total kinetic energy of an ideal atomic gas is given by
From this, it can be seen that an increase in temperature causes an increase in the kinetic energy of the particles in an ideal atomic gas.
This can also be applied to other ideal gasses with more complex molecules and real gasses.
The kinetic energy of a single particle is given by
They move faster.
“Temperature” is an arbitrary measurement of heat energy (enthalpy). When the temperature of something increases it is because there is a source of higher energy interacting with the system.
Without worrying about what the source is, the effect is to transfer the energy as heat. When molecules are heated (absorb energy) they move faster – some, or all of the heat energy is converted to kinetic energy.
So, when a gas is heated, the effect is to make the molecules move faster. It is this more rapid, energetic motion of the molecules that create an increased pressure in a container due to the collisions of the molecules with the container walls.