UNIT CH1 - Controlling and Using Chemical Changes

Controlling and Using Chemical Changes (in order to make things, produce energy and solve environmental problems)

This unit begins with some important fundamental ideas about atoms and the use of the mole concept in calculations. Three key principles governing chemical change are then studied, viz., the position of equilibrium between reactants and products, the energy changes associated with a chemical reaction and the rate at which reactions take place. These principles are then applied to some important problems in the fields of chemical synthesis, obtaining energy and the maintenance of the environment.

2.1 Chemical equilibrium and acid-base reactions

Candidates should be able to:

(a) understand the terms reversible reaction and dynamic equilibrium;

(b) recall and understand Le Chatelier's principle and apply it qualitatively to deduce the effects of changes in temperature and in pressure or concentration, on a system at equilibrium

(c) understand the nature of acids as donors of H+(aq) and bases as acceptors of H+(aq) and apply this to their behaviour in aqueous solution;

(d) appreciate the usefulness of the pH scale in describing the degree of acidity to the general public;

(e) use the concept of the mole in calculations involving acid - base titration data;

(f) recall outline details of experimental procedures in acid-base titrations, including apparatus and methods used;

(g) recall that carbon dioxide is an acidic gas and its interaction with water including its effect on the carbonate/hydrogen carbonate equilibrium in sea-water.