If the amount of gas is decreased to 0.755 mol, holding the volume and temperature constant, the pressure will decrease because

Question

A 1.51 mol sample of O₂ gas is confined in a 36.6 liter container at 22.3 °C.

If the amount of gas is decreased to 0.755 mol, holding the volume and temperature constant, the pressure will decrease because:

Choose all that apply.

With fewer molecules in the container, the molecules have lower average speeds.

As the number of molecule-wall collisions increases, the force per collision decreases.

With fewer molecules per unit volume, the molecules hit the walls of the container less often.

With lower average speeds, on average the molecules hit the walls of the container with less force.

None of the Above

Answer 1

C. With fewer molecules per unit volume, the molecules hit the walls of the container less often.

When you decrease the number of moles, you directly decrease the number of molecules able to hit the wall of the container. As this is the definition of pressure, the pressure decrease as a result.

Let me know if you need more explanations.

Jesse