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Unformatted text preview: ; -:. a .Lz:XA»E£/.\»L°nc: .. t. e'j‘éfnw'nﬂtdii . CAMBRIDGE INTERNATIONAL EXAMINATIONS
General Certificate of Education Advanced Level BIOLOGY 9700/05 Paper 5 Practical Test A2 May/June 2003
CONFIDENTIAL INSTRUCTIONS Great care should be taken to ensure that any confidential information given does not
reach the candidates either directly or indirectly. ERRATUM Instructions for preparing apparatus Please retain the original Confidential Instructions. For question 1 the instructions (l) and (ii) should
be crossed out as they are replaced by the information that follows. There is a new instruction, (vii).
The remaining instructions are unchanged. Page 2, Question 1 Replacement Instruction (i) Three test tubes, labelled F1, F2 and F3, in a test tube rack.
F1 to contain 5 cm3 of distilled water. F2 to contain 5 cm3 of urea solution. The solution to be made by dissolving 10 g of urea in 100 cm3
of distilled or deionised water. F2 should not be less concentrated than this in order to avoid the
possibility that the experiment might not work under examination conditions. F3 to contain 5 cm3 of urea solution. The solution to be made up by dissolving 2 g of urea in 100 cm3
of distilled or deionised water. Alternatively, if there are not many candidates it may be more convenient to dilute a sample of solution F2 (e.g. by diluting 10 cm 3 of solution F2 made up to 50 cm3
with distilled or deionised water). Each test tube should be fitted with a bung. Replacement Instruction (ii) 30 cm3 of urease solution, labelled F4, made by dissolving two tablets (0.4 g) in 100 cm3 of distilled
or deionised water. Well before the examination, test the activity of the urease solution by mixing 5
cm3 of urease solution F4 and 5 cm3 of urea solution F2 in a test tube. Moist red litmus paper, held in
the air in the top of the test tube with a bung, should show a colour change within 5 minutes. If
necessary, increase the concentration of the urea solution F2 to 15 g of urea in 100 cm3 of distilled or
deionised water, to ensure that this happens. Please note any such changes on the back of the back
cover of the script whose name appears first on the attendance register. New Instruction (vii) Information required from the teacher present: The teacher present in the examination room at the start of the test should carry out question 1
(a) (i) and (ii) and enter their results on a spare copy of the examination paper, clearly marked
‘Teacher’s Results’ and showing the Centre'Number. This should be returned with the scripts. ...
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- Spring '11
- Distillation, Test Tube, Purified water, Aquarium