Question

If a gas expands at constant temperature:

• A. The pressure decreases
• B. The kinetic energy of the molecules remains the same
• C. The kinetic energy of the molecules decreases
• D. The number of molecules of the gas increases

Answer 1

Answer: (A), (B)

The pressure decreases
The kinetic energy of the molecules remains the same

According to Boyle's law, when gas is expanded at a constant temperature, its pressure decreases. Kinetic energy is a function of temperature only, so it remains the same.

Hence, the correct options are $\text{A}$ and $\text{B}$