Question

what happens when a higher number of gas particles collide with the walls of the container?
the pressure increases
the volume decreases
the mass increases

Explanation:

Gas pressure is defined by the frequency and force of particle collisions with container walls. More collisions (from a higher number of particles, assuming constant volume/temperature) directly increase pressure. Volume depends on container flexibility, not collision frequency alone; mass is fixed as particles are not added/removed.

Answer:

the pressure increases