CHEMISTRY PRACTICAL SPECIMEN:
1. Great care should be taken to ensure that the information given in items 2 and 3 below does not reach the candidates either directly or indirectly before the examination.
2. In addition to the fittings and reagents normally contained in a chemistry laboratory, the following apparatus and materials will be required by each candidate.
(a)one burette of 50cm³ capacity.
(b)one pipette, either 20cm³ or 25cm³. All candidates at one centre must use pipettes of the same volume. These should be clean and free from grease.
(c)the usual apparatus for titration.
(d)the usual apparatus and reagents for qualitative work. Including the following with all reagents appropriately labelled.
(i) dilute sodium hydroxide solution.
(ii) dilute hydrochloric acid.
(iii) dilute trioxonitrate(v) acid
(iv) silver trioxonitrate(v) solution.
(v) barium chloride solution.
(vi) aqueous ammonia.
(vii) lime water.
(viii) red and blue litmus paper.
(ix) dilute tetraoxosulphate(vi) acid.
(e) Spatula
(f) filtration apparatus.
(g) one beaker
(h) one boiling tube
(i) four test tubes.
(j) starch solution as indicator.
(k) mathematical table/calculator
(l) wash bottle containing distilled/deionized water.
3. Each candidate should be supplied with the following where n is the candidate’s serial number.
(a) 150cm³ of sodium trioxosulphur sulphate(vi) solution in a corked flask or bottle, labelled “An”. These should all be the same containing 6.0g of Na2S2O3 per dm³ of solution.
(b) 150cm³ of iodine in potassium iodide solution in a corked flask or bottle labelled “Bn”. These should all be the same containing 2.5g of I2 and 1.67g of KI per dm³ of solution.
(c) One spatulafull of a uniform mixture of NaCl and CuCO3 in a specimen bottle labelled “Cn”. The components of the mixture should be in the ratio 1:2 by mass
4. In all cases, more materials may be issued if required.
5. The actual concentrations of A and B must be stated on the Supervisor’s Report form. The candidates will assume that the concentrations are exactly as stated in the question paper.
