Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.
Understanding
- I can list the four assumptions of the classical ideal gas model and say what each one means for the atoms. (Guide: “The ideal gas model”; Practice Q1)
- I can explain when a real gas behaves most like an ideal gas, and which assumptions fail at high pressure or near condensation. (Guide: “The ideal gas model”)
- I can state PV = nRT = Nk_BT, name every symbol with its SI unit, and explain why R = N_A k_B. (Guide: “The ideal gas law”)
- I can explain, using moving atoms, why heating a gas at constant volume raises its pressure. (Guide: “Using the law to predict changes”; Practice Q7b)
Calculation and skills
- I can convert °C to K, L to m³ and kPa to Pa before using PV = nRT. (Guide: “The ideal gas law”; Practice Q3, Q5)
- I can find n or N for a gas from P, V and T. (Guide: Worked example 1; Practice Q5)
- I can use P₁V₁/T₁ = P₂V₂/T₂ to find a new pressure, volume or temperature for a fixed amount of gas. (Guide: Worked example 1; Practice Q3, Q5, Q7c)
- I can predict the factor by which one variable changes when two others change by known factors. (Guide: “Using the law to predict changes”; Practice Q2)
- I can plot P against T in °C, draw a best-fit line and extrapolate it to find absolute zero. (Guide: Worked example 2; Practice Q6)
- I can find the amount of gas from the gradient of a P–T or V–T graph. (Guide: Worked example 2; Practice Q6c)
Reasoning
- I can say which graph of gas data gives a straight line through the origin, and what its gradient means. (Guide: “Graphs of gas behaviour”; Practice Q4)
- I can explain why absolute zero is found by extrapolation and why different gas samples give the same intercept. (Guide: “Absolute zero from a graph”; Practice Q6b, Q6d)
- I can compare the pressures of gas samples using N/V and T, and reject the idea that more atoms always means more pressure. (Practice Q7)
All ticked? Move on to Topic 9.3, thermal energy transfer and equilibrium, or return to the course roadmap.