ConceptConceptDocsDocuments

CAIE A-Level Physics 15.3.2 Gas Pressure from Molecular Motion

Practise explaining gas pressure through molecular wall collisions, deriving pV = ⅓Nmc² and using it to calculate pressure, volume or molecular speed.

Syllabus
2028–2030
Course
Physics 9702
Level
A2

Exam points

  • explain how molecular collisions with container walls produce gas pressure
  • derive pV = 1/3 Nmc² from molecular momentum transfer and the kinetic-theory model
  • use pV = 1/3 Nmc² to calculate pressure, volume, number of molecules, mass or mean-square speed

15.3.2—How molecular movement causes the pressure exerted by a gas and derive and question 1

[Maximum number: 1]

The pressure p and volume V of an ideal gas are related to the density ρ\rho of the gas by the expression

p=13ρ⟨c2⟩.p=\frac{1}{3} \rho\left\langle c^{2}\right\rangle .

State what is meant by the symbol ⟨c2⟩\left\langle c^{2}\right\rangle.

All question bank results loaded