Answer: doubles.
- A doubles
- B halves
- C stays the same
- D becomes four times
Correct answer: A. doubles
Explanation: Pressure is proportional to number density at fixed T, so doubling the molecules doubles the pressure.
Not all gas molecules move at the same speed - the Maxwell-Boltzmann distribution shows the spread, with the most probable speed vp slightly less than the average vavg, which is slightly less than the root-mean-square speed vrms used in the pressure formula.
Concept context
Kinetic theory of gases connects molecular motion to pressure and temperature, explaining gas laws, specific heats, and molecular speeds.