Equilibria

You will be able to

• Explain dynamic equilibrium in a closed system as equal forward and reverse rates with constant concentrations.
• Use Le Chatelier's principle to deduce the effect of a change in concentration, pressure, temperature or a catalyst on the position of equilibrium.
• Deduce expressions for Kc and Kp and state which changes alter the value of the equilibrium constant.

You will be able to

• Sketch and compare the pH titration curves for strong and weak acids with strong and weak alkalis.
• Explain qualitatively why a weak acid has a higher starting pH than a strong acid of the same concentration.
• Select a suitable indicator for an acid-alkali titration from its colour-change range and the steep part of the curve.