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 reaction below is correct? ? 222 4 218 88 2Ra  X Y A Y has fully filled 4f orbitals. B Y has more neutrons than Ra. C Y exists as a diatomic molecule. D The first ionisation energy of Y is greater than that of X. 4 The first six ionisation energies (in kJ mol –1) of a Period 2 element, Z, are shown. 1090 2350 4610 6220 37831 47277 Which diagram represents the arrangement of electrons in the ion, Z2–? 1s 2s 2p A B C D 5 Dinitrogen pentoxide, N 2O5, exists as covalent molecules, O 2NONO2 in the gas phase, but as the ionic [NO2 +NO3 ] in the solid phase or in solution. Which of the following statements is correct? A There are a total of 4 double bonds in N 2O5. B N 2O5 is a non-polar molecule. C NO 3  is isoelectronic with CO3 2. D NO2 + has a smaller bond angle than NO3 . 6 Which carbon-carbon bond ( I, II, III or IV) in molecule X is the shortest? C H C H C H CH3 C C OH OCCCH3 molecule X A I B II C III D IV I II III IV

4 Raffles Institution 9647/01/S/14 [Turn Over 7 A typical ping pong ball is made of an air-filled plastic and has a volume of 40.0 cm 3. At 27 oC and 105.6 kPa, a slightly dented ping pong ball of volume 38.5 cm 3 is filled with air. To restore its spherical shape, the air inside the dented ball is heated to a constant temperature of 60 oC. The pressure of air inside the ball increases and creates a uniform outward force. Assuming that the air inside the ping pong ball behav es ideally, what is the pressure of air inside the ball at 60 oC when the shape is restored? A 113 kPa B 122 kPa C 226 kPa D 244 kPa 8 Use of the Data Booklet is relevant to this question. Nitrogen exists as a diatomic molecule, N2, and phosphorus as the molecule as shown. Imagine that nitrogen were to form a similar molecule, N4. 2N2(g)  N4(g) What would be the value of ∆H for the above reaction? A +1028 kJ mol –1 B +1348 kJ mol –1 C +1954 kJ mol–1 D +2628 kJ mol–1 9 The following reaction is thermodynamically feasible at low temperature. CO(g) + 2H2(g)  CH3OH(l) What are the signs of ∆Hr and ∆Sr for the reaction? ∆Hr ∆Sr A – – B + – C – + D + + 10 Quarter-life, t1/4, of a radioactive isotope is defined as the time taken for the sample to decay to ¼ its original amount. Potassium-argon dating is used to determine the age of a rock. 40K is a radioactive isotope of potassium and it decays to 40Ar with a constant t1/4 of 2.50 x 109 years. A sample of moon rock was found to contain 6.25% of the original amount of 40K. How old is the rock? A 2.50 x 10 9 years B 5.00 x 10 9 years C 7.50 x 109 years D 1.00 x 1010 years

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6 Raffles Institution 9647/01/S/14 [Turn Over 14 Use of the Data Booklet is relevant to this question. The E cell of a voltaic cell is found to be +0.19 V. One of the half-cells contains 1 mol dm –3 each of K2S2O8(aq) and K2SO4(aq). If both half-cells are under standard conditions, what is the identity of the species that will be used up in the other half-cell? A Co 2+ B Fe 2+ C Co 3+ D Fe 3+ 15 During electrolysis under suitable conditions, 0.015 mol of manganese is deposited on the cathode when 0.090 mol of electrons is passed through a manganese-containing elect