Question

Why does pressure change in this way? Select all that apply.

Kinetic energies of molecules increase.

Speeds of molecules increase.

Number of collisions per second increase.

Answer 1

All three. Briefly:

- Kinetic energies of molecules increase: Temperature rise increases the average translational kinetic energy (½mv²), which raises pressure.
- Speeds of molecules increase: Higher average kinetic energy means larger root-mean-square speeds, so molecules hit the walls with greater speed.
- Number of collisions per second increase: Faster molecules strike the walls more often, so collision frequency goes up.

Together, each collision transfers more momentum and collisions happen more frequently, so force on the walls (pressure) increases.