Older MCQs might not have the typical A, B, C,
D
choices. They
have choices 1, 2, 3, and a combination of them is the answer. Below is the key that maps such
combinations to the answer.
A
1, 2 and 3 are correct
B
1 and 2 only are correct
C
2 and 3 only are correct
D
1 only is correct
perform calculations including use of the mole concept, involving: (a) reacting masses (from formulas and equations) including percentage yield calculations (b) volumes of gases (e.g. in the burning of hydrocarbons) (c) volumes and concentrations of solutions (d) limiting reagent and excess reagent (When performing calculations, candidates’ answers should reflect the number of significant figures given or asked for in the question. When rounding up or down, candidates should ensure that significant figures are neither lost unnecessarily nor used beyond what is justified (see also Mathematical requirements section)) (e) deduce stoichiometric relationships from calculations such as those in 2.4.1(a)–(d)
state the names and formulas of the common acids, limited to hydrochloric acid, HCl, sulfuric acid, \( H_2SO_4 \), nitric acid, \( HNO_3 \), ethanoic acid, \( CH_3COOH \)
describe: (a) the redox reaction with reactive metals to produce a salt and H\(_2\)(g) (b) the neutralisation reaction with alkalis to produce a salt and H\(_2\)O(l) (c) the acid–base reaction with carbonates to produce a salt and H\(_2\)O(l) and CO\(_2\)(g) (d) esterification with alcohols with concentrated H\(_2\)SO\(_4\) as catalyst (e) reduction by LiAlH\(_4\) to form a primary alcohol
