RI_H2_Chem_P1 Prelim

Raffles Institution 9647/01/S/14 [Turn Over RAFFLES INSTITUTION 2014 YEAR 6 PRELIMINARY EXAMINATION HIGHER 2 CHEMISTRY 9647/01 Paper 1 Multiple Choice 26 September 2014 1 hour Additional Materials: Mult iple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Do not open this question booklet until you are told to do so. Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, class and index number in the spaces provided on the Answer Sheet. 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 to be correct and record your choice with a soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. This document consists of 20 printed pages.

2 Raffles Institution 9647/01/S/14 [Turn Over Section A For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 Chromate( VI) ions can undergo condensation in the presence of acid to form dichromate( VI) ions via the following equation: 2CrO4 2– + 2H+ /g3Cr2O7 2– + H2O Further condensation can proceed in strong ac idic solutions to form trichromates and tetrachromates. Which pair shows the formulae of a trichromate and a tetrachromate ion? trichromate tetrachromate A Cr3O10 2– Cr4O14 2– B Cr3O10 2– Cr 4O13 2– C Cr3O11 2– Cr 4O14 2– D Cr3O11 2– Cr 4O13 2– 2 The degree of unsaturation of an unknown fatty acid is usually determined by its iodine number, which is the mass of iodine atoms that add across all C=C bonds in 100 g of fatty acid in the following addition reaction. Iodine is introduced to the fatty acids in the form of ICl as ICl is more reactive than I2. In one reaction, 1.72 x 10 –3 mol of ICl (in excess) were added to 0.100 g of fatty acid, and the excess ICl is converted to I2 as follows: ICl + KI  KCl + I2 The I2 produced was titrated against sodium thiosulfate, Na2S2O3. I2 + 2Na2S2O3  2NaI + Na2S4O6 It was found that 1.39 x 10–3 mol of Na2S2O3 were required for complete titration. What is the iodine number of the unknown fatty acid? A 88 B 130 C 177 D 260

3 Raffles Institution 9647/01/S/14 [Turn Over 3 Which statement about the reactants and products of the radioactive decay reac