Boyle's law
3 marks · NormalExplain, in terms of the particle model, why increasing the temperature of a gas at constant volume increases the pressure of the gas.
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Common mistakes: Refers only to expansion, not pressure.; Forgets to mention nature of pressure.
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Marking points
M1 · 1 mark · States that increasing temperature increases the kinetic energy of particles.
M1 · 1 mark · Describes that particles collide more frequently or with more force with the walls.
A1 · 1 mark · Concludes that this causes an increase in pressure.
Worked solution
When you increase the temperature of a gas, the particles gain kinetic energy and move faster. Since the volume is constant, the faster moving particles hit the walls of the container more frequently and with greater force. This results in a greater force per unit area on the walls, which means the pressure increases.