Question

when the gas in container is heated the pistons moves outwards why

Answer 1

Explanation:

We know that gaseous state molecules posses greatest kinetic energy than the molecules in solid or liquid state. This is why they do not have a specific volume.

When gas in a container is heated, the molecule's temperature increases and we know that temperature is directly proportional to kinetic energy. Thus, the kinetic energy of molecules increase.

As a result, molecules move faster and exert force on the walls of the container and the piston due to which it moves upward.