When a gas is heated it's molecules begin to move faster and farther apart, juat as all other states of matter will when heated.
The speed of the molecules speeds up when the gas is heated.
it moves faster
Liquid to a gas
Gas molecules change their motion when they bounce into the surfaces of their containers. If the surfaces absorb the impact, then energy is transfered out of the system and particle speed decreases.
Molecules move faster when heated -- no matter what state they're in.
When the molecules in a body move with increased speed, it's possible that the body will change from a
It is true that, in a rigid container, when the speed of the gas molecules increases, the temperature of the gas rises. This has nothing to do with the speed or lack of speed of the gas as a whole.
The molecules absorb more energy, more speed and can be released from the liquid.
they get heated up and evaporate
That could cause a change from solid to liquid, or from liquid to gas.
Liquid to gas
As the molecules in a body move with increased speed, i.e. increasing kinetic energy, it is possible that the body will change from the solid phase to the liquid phase, or the liquid phase to the gas phase, and in some cases from the solid directly to the gas phase.