Final answer:
When you double the temperature of a gas at constant volume, the average translational kinetic energy of the molecules also doubles.
Step-by-step explanation:
The average translational kinetic energy of a gas molecule is directly proportional to its temperature.
When you double the temperature of a gas at constant volume, the average translational kinetic energy of the molecules also doubles. This is because temperature is a measure of the average kinetic energy of the molecules in a gas.
By increasing the temperature, the molecules gain more kinetic energy, causing them to move faster and have a higher average translational kinetic energy.