The main assumptions of the kinetic molecular theory of gases are: 1. gases are made up of molecules which are relatively far apart. 2. the molecules are in motion at high speeds. 3. the molecules are perfectly elastic. 4. increase in temperature increases the kinetic energy of the molecules. the assumption that explains charles' law is: 1 2 3 4 1 and 3

The correct answer is Assumption 4.

Explanation:

Charles' law is defined as the law which relates volume and temperature of the gas.

This law states that volume of the gas is directly proportional to the temperature of the gas at constant pressure.

Mathematically,

    (at constant pressure)

By taking Assumption 4, increase in kinetic energy will increase the average kinetic energies of the particles which further increases the effective elastic collision between them and due to these collisions, the spaces between the particles increases and thus, the volume increases.

So, increase in temperature will increase the volume of the gas.

Thus, the correct answer is Assumption 4.