7.1 Acids and Bases

(a) describe the meanings of the terms acid and alkali in terms of the ions they produce in aqueous solution and their effects on Universal Indicator

(b) describe how to test hydrogen ion concentration and hence relative acidity using Universal Indicator and the pH scale

(c) describe qualitatively the difference between strong and weak acids in terms of the extent of ionisation

(d) describe the characteristic properties of acids as in reactions with metals, bases and carbonates

(e) state the uses of sulfuric acid in the manufacture of detergents and fertilisers; and as a battery acid

(f) describe the reaction between hydrogen ions and hydroxide ions to produce water, H+ + OH– → H2O, as neutralisation

(g) describe the importance of controlling the pH in soils and how excess acidity can be treated using calcium hydroxide

(h) describe the characteristic properties of bases in reactions with acids and with ammonium salts

(i) classify oxides as acidic, basic, amphoteric or neutral based on metallic/non-metallic character.

7.2 Salts

(a) describe the techniques used in the preparation, separation and purification of salts as examples of some of the techniques specified in Section 1.2(a) (methods for preparation should include precipitation and titration together with reactions of acids with metals, insoluble bases and insoluble carbonates)

(b) describe the general rules of solubility for common salts to include nitrates, chlorides (including silver and lead), sulfates (including barium, calcium and lead), carbonates, hydroxides, salts of Group I cations and ammonium salts

(c) suggest a method of preparing a given salt from suitable starting materials, given appropriate information.

7.3 Ammonia

(a) describe the use of nitrogen, from air, and hydrogen, from the cracking of crude oil, in the manufacture of ammonia

(b) state that some chemical reactions are reversible, e.g. manufacture of ammonia

(c) describe the essential conditions for the manufacture of ammonia by the Haber process

(d) describe the displacement of ammonia from its salts.