Practise explaining gas pressure through changes in molecular momentum when particles collide with container walls using CAIE IGCSE Physics questions and mark schemes.
A rubber balloon is inflated with helium and sealed so that no helium escapes.
The balloon is positioned immediately below the ceiling in a room.
Heaters are switched on and the temperature of the air in the room increases.
The temperature of the helium in the balloon increases and as the rubber stretches, the volume occupied by the helium increases.
As the rubber stretches and the volume of the helium increases, the pressure of the helium remains constant.
Explain, in terms of the particles of helium, how the pressure of the helium remains constant.
(higher temperature means) particles collide (with rubber) harder / with more force / with greater momentum (change)
(larger volume means) particles collide (with rubber) less frequently
OR
(larger volume means) larger (surface) area (for particle collisions)
effect of larger volume cancels effect of increased temperature / owtte
OR
the effect of larger area cancels the effect of larger force / owtte
OR
P=F / A so the two changes cancel each other/owtte