(a) describe methods of purification by the use of a suitable solvent, filtration and crystallisation,
distillation and fractional distillation, with particular references to the fractional distillation of crude oil,
liquid air and fermented liquor
(b) suggest suitable methods of purification, given information about the substances involved
(c) describe paper chromatography and interpret chromatograms including comparison with ‘known’
samples and the use of Rf values
(d) explain the need to use locating agents in the chromatography of colourless compounds
(e) deduce from the given melting point and boiling point the identities of substances and their purity
(f) explain that the measurement of purity in substances used in everyday life, e.g. foodstuffs and
drugs, is important
