Which of the following is not an assumption made by kinetic molecular theory?
1. an ideal gas steadily loses energy due to elastic collisions with the walls of the container.
2. the kinetic energy of a gas is solely dependent on the temperature.
3. gas particles are constantly moving in random directions.
4. the volume of the gas particles is negligible compared to the size of the container.
5. an ideal gas does not exhibit attractive or repulsive forces.

1 = An ideal gas steadily loses energy due to elastic collisions with the walls of  container

Explanation:

The first option is not an assumption of kinetic molecular theory because according KMT the collision of gas molecules with each other and wall of container is perfectly elastic. None of the energy is lost during these collisions.

While all other options are postulates of kinetic molecular theory.

1. The kinetic energy of gas molecules is only depend upon the temperature.

2. The gas molecules are randomly moves in any direction and thus colloid with each other and wall of container.

3. The volume of gas particles is negligible as compared to the volume of container.

4. The ideal gas does not exhibit attractive and repulsive forces.