Loading…
Loading…
GCSE Physics · key term
A sample of gas in which no gas enters or leaves, so the number of gas particles remains unchanged.
Used by AQA and Edexcel
Specification 4.3.3.2 · Paper 1
A sample of gas in which no gas particles enter or leave, so its mass and number of particles remain unchanged.
Revise: Pressure in gasesConsider a fixed mass of gas whose temperature is kept constant. Because no gas enters or leaves, the number of molecules stays the same. Constant temperature also means that their average kinetic energy, and therefore their typical speed, stays the same.
Specification 14.13, 14.18P, 14.19P · Paper 2
A condition in which no gas enters or leaves, so the amount of gas and the number of particles remain unchanged.
Revise: Temperature and PressureFor the same fixed mass of gas in the same volume, the pressure therefore decreases.
A quantity of gas containing the same number of particles throughout a change.
Keep all three conditions in your explanation: a fixed mass of gas, constant temperature and a changing volume.
Create a free account to read GCSE Physics revision notes for your exam board and track your progress.