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 state Le Châtelier’s principle and explain that the shift only partly undoes the stress. (Guide: “What Le Châtelier’s principle says”, Figure 1)
- I can explain a shift in terms of the forward and reverse rates becoming unequal and then equal again. (Guide: “Why it works: rates”)
- I can name the changes that cause no shift: a catalyst, extra solid or pure liquid, and an unreactive gas added at constant volume. (Guide: “Changes that cause no shift”; Practice Q1, Q6(c))
- I can say which stress changes the value of K, and which do not. (Guide: Stress 2; Practice Q3)
Skills
- I can predict the shift when a reactant or product is added, or removed by precipitation or reaction. (Guide: Worked example 1; Practice Q2, Q6(d))
- I can write heat into an equation and predict the effect of heating or cooling. (Guide: Stress 2; Practice Q1, Q6(b))
- I can count gas molecules to predict the effect of a volume change, including the case of equal numbers. (Guide: Stress 3; Practice Q4, Q6(a))
- I can count dissolved particles, leaving out solvent water, to predict the effect of dilution. (Guide: Stress 4; Practice Q5(b))
Reasoning
- I can predict what an observer would see: a colour change, a pH change or a temperature change. (Guide: “What you would actually see”; Practice Q3, Q5(c))
- I can separate the instant effect of compressing a gas from the shift that follows. (Guide: Worked example 2; Practice Q4)
- I can deduce the sign of ΔH from an observed effect of temperature. (Practice Q5(a))
- I can evaluate a claim about adding a solid to a heterogeneous equilibrium. (Practice Q7)
All ticked? Move on to Topic 7.10, Reaction Quotient and Le Châtelier’s Principle, or return to the course roadmap.