Dynamic equilibrium, Kc and Kp with their units, the reaction quotient, the Kp = Kc(RT)^Δn conversion and Le Chatelier applied to Haber, Contact and PCl₅ — with degree-of-dissociation numericals worked twice.
Unit 1, Physical chemistry, carries 17 of the 50 chemistry marks — joint-heaviest in the subject. With fourteen chapters sharing them, this one averages a little over one (MEC publishes weights by unit, not by chapter).
The MEC scope line runs: Physical and chemical equilibrium. Law of mass action and equilibrium constants. Reaction quotient. Relationship between Kp and Kc. Le Chatelier's principle and its applications. The headings below are its points, in MEC's order.
Three ways it comes: recall (the units of Kc for a given equation, the catalyst and pressure of the Haber process); understanding (which way an equilibrium moves when the vessel is compressed, why a catalyst leaves K untouched); application (a Kp–Kc conversion, a degree of dissociation from vapour density).
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