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