DHS Prelim P1_Ans

This question paper consists of 20 printed pages and 1 blank page. © DHS 2015 [Turn over Name: Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination 2015 Year 6 H2 CHEMISTRY 9647/01 Paper 1 Multiple Choice 29 September 2015 1 hour Additional Materials: Optical Mark Sheet Data Booklet INSTRUCTIONS TO CANDIDATES 1 Write your name and class on this question paper. 2 There are Forty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Optical Mark Sheet. 3 Each correct answer will score one mark. A mark will not be deducted for wrong answer. 4 Any rough working should be done in this booklet. 5 You may use a calculator.

2 © DHS 2015 9647/01 [Turn Over Section A For each question, there are four possible answ ers, A, B, C, and D. Choose the one you consider to be correct. 1 The use of Data Booklet is relevant to this question. Peroxodisulfate ions convert iodide ions into iodine slowly. S2O8 2–(aq) + 2I–(aq)  2SO4 2–(aq) + I2(aq) The ra te of the re action can be increased by the addition of catalysts such as aqueous iron(III) ions. A possible catalyst reaction pathway involves the following steps: Step 1 2Fe3+(aq) + 2I–(aq)  2Fe2+(aq) aq) + I2(aq) Step 2 S2O8 2–(aq) + 2Fe2+(aq) aq)  2Fe3+(aq) + 2SO4 2–(aq) Which of the following statements is incorrect? A Fe2+ is a stronger reducing agent than I–. B S2O8 2– is a stronger oxidising agent than Fe3+. C The E cell for step 2 is more positive than step 1. D Aqueous cobalt(II) ions can be used as a catalyst for this reaction. 2 0.5 g of zinc powder was found to reduce an acidified solution of 25.50 cm 3 of 0.200 mol dm–3 VO2 +. Which one of the following is the reduced product of VO2 +? A VO3 – B VO2+ C V3+ D V2+

3 © DHS 2015 9647/01 [Turn Over 3 Which graph best represents the behaviour of a fixed mass of ideal gas at constant temperature? A B C D 4 The interhalogen compound BrF3 is a volatile liquid which autoionises as follows. 2BrF3 BrF2 + + BrF4 – The electrical conductivity of BrF3 decreases with increasing temperature. Which one of the following statement is correct? A The autoionisation process is endothermic and the shape of the anion is square planar. B The autoionisation process is exothermic and the shape of the cation is linear. C The autoionisation process is endothermic and the shape of the anion is tetrahedral. D The autoionisation process is exothermic and the shape of the cation is bent. pV p p  p V V

4 © DHS 2015 9647/01 [Turn Over 5 The