Equilibria

Learning objectives

Explain reversible reactions and dynamic equilibrium in a closed system, and use Le Chatelier's principle to predict how changes in concentration, pressure or temperature, or adding a catalyst, affect the position of equilibrium

Write Kc and Kp expressions with units, calculate partial pressures from mole fractions, and state that only a change of temperature alters the value of an equilibrium constant

Calculate equilibrium amounts and values of Kc or Kp from initial quantities and one equilibrium measurement, using an initial–change–equilibrium table

Explain the temperature, pressure and catalyst chosen for the Haber process and the Contact process as compromises between yield, rate and cost

Describe Brønsted–Lowry acids and bases, distinguish strong from weak acids by their degree of dissociation, and compare them using pH, conductivity and the rate of reaction with magnesium

Sketch how pH changes during titrations of strong or weak acids with strong or weak alkalis, marking the steep section, and choose an indicator such as methyl orange or phenolphthalein whose colour change falls within it