1.1 Experimental design

(a) name appropriate apparatus for the measurement of time, temperature, mass and volume, including burettes, pipettes, measuring cylinders and gas syringes

Pure Chem | Combined Sci (Chem) | Combined Sci (Chem) NA

(b) suggest suitable apparatus, given relevant information, for a variety of simple experiments, including collection of gases and measurement of rates of reaction.

Pure Chem | Combined Sci (Chem) | Combined Sci (Chem) NA

1.2 Methods of purification and analysis

(a) describe methods of separation and purification for the components of mixtures, to include:

(i) use of a suitable solvent, filtration and crystallisation or evaporation

(ii) sublimation

(iii) distillation and fractional distillation (see also 11.1(b))

(iv) use of a separating funnel

(v) paper chromatography

Pure Chem | Combined Sci (Chem) | Combined Sci (Chem) NA

(b) suggest suitable separation and purification methods, given information about the substances involved in the following types of mixtures:

(i) solid-solid

(ii) solid-liquid

(iii) liquid-liquid (miscible and immiscible)

Pure Chem | Combined Sci (Chem) | Combined Sci (Chem) NA

(c) interpret paper 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 (knowledge of specific locating agents is not required)

(e) deduce from given melting point and boiling point data 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.

1.3 Identification of ions and gases

(a) describe the use of aqueous sodium hydroxide and aqueous ammonia to identify the following aqueous cations: aluminium, ammonium, calcium, copper(II), iron(II), iron(III), lead(II) and zinc (formulae of complex ions are not required)

(b) describe tests to identify the following anions: carbonate (by the addition of dilute acid and subsequent use of limewater); chloride (by reaction of an aqueous solution with nitric acid and aqueous silver nitrate); iodide (by reaction of an aqueous solution with nitric acid and aqueous silver nitrate); nitrate (by reduction with aluminium in aqueous sodium hydroxide to ammonia and subsequent use of litmus paper) and sulfate (by reaction of an aqueous solution with nitric acid and aqueous barium nitrate)

(c) describe tests to identify the following gases: ammonia (using damp red litmus paper); carbon dioxide (using limewater); chlorine (using damp litmus paper); hydrogen (using a burning splint); oxygen (using a glowing splint) and sulfur dioxide (using acidified potassium manganate(VII)).