Which of the following would increase the rate of effusion of a gas?

• A. Decreasing the pressure of the gas
• B. Increasing the temperature of the gas
• C. Increasing the molar mass of the gas
• D. Using a container with thicker walls

Answer: (B)

Verified step by step guidance

1. Recall Graham's law of effusion, which states that the rate of effusion of a gas is inversely proportional to the square root of its molar mass: \(\text{Rate} \propto \frac{1}{\sqrt{M}}\).
2. Understand that the rate of effusion also depends on the average speed of gas molecules, which increases with temperature according to the kinetic molecular theory.
3. Analyze each option: Decreasing pressure does not directly affect the rate of effusion because effusion depends on molecular speed and molar mass, not pressure.
4. Increasing temperature increases the average kinetic energy and speed of gas molecules, thus increasing the rate of effusion.
5. Increasing molar mass decreases the rate of effusion, and using thicker container walls does not affect the molecular speed or effusion rate.