Question

At constant volume, for a fixed number of moles of a gas, the pressure of the gas increases with rise of temperature due to:

• A. increase in average molecular speed
• B. increase rate of collisions amongst molecules
• C. increase in molecular attraction
• D. decrease in mean free path

Answer 1

Answer: (A)

increase in average molecular speed

The average speed of the gas is given by the term $\sqrt{\frac{8RT}{\pi M}}$.
When volume and mass are constant, the average speed increases with increase in the temperature and the frequency of collisions of molecules with walls of the container increases.
This increases the pressure of the gas.