RI H2 CHEM P1 Prelim

© Raffles Institution 2016 9647/01/S/16 [Turn Over 1 RAFFLES INSTITUTION 2016 YEAR 6 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9647/01 Paper 1 Multiple Choice 26 September 2016 1 hour Additional Materials: Multiple 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 in 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 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 the question booklet. This document consists of 18 printed pages.

© Raffles Institution 2016 9647/01/S/16 [Turn Over 2 Section A For each question, there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 Which of the following statements best explains why helium has the highest first ionisation energy among all the elements in the Periodic Table? A It is unreactive. B It is the least electronegative element. C It has only one completely filled principal quantum shell. D Its valence electron is poorly shielded and is very close to the nucleus. 2 When a beam of protons travelling at the same speed passes through an electric field of constant strength, the protons, 1H+, are deflected through an angle of +12o. Under identical conditions, which particle would be deflected through an angle of +8o? A 2H+ B 3He2+ C 6Li2+ D 12C3+ 3 Use of the Data Booklet is relevant to this question. Which particle has three unpaired electrons? A V3+ B F2+ C Ni D S– 4 FeSO4 reacts with K2Cr2O7 in acid solution according to the following equation. 14H+ + 6Fe2+ + Cr2O72–  2Cr3+ + 6Fe3+ + 7H2O A 20.0 cm 3 sample of FeSO 4 solution required 13.1 0 cm3 of 0.100 mol dm –3 acidified K2Cr2O7 for complete reaction. What was the concentration of the FeSO4 solution? A 0.0655 B 0.153 C 0.393 D 0.916

© Raffles Institution 2016 9647/01/S/16 [Turn Over 3 5 1,3,5-triazine is an aromatic compound and its structure resembles that of benzene. 1,3,5-triazine Which statement about 1,3,5-triazine is correct? A Its empirical formula is CN. B A molecule of 1,3,5-triazine has six  bonds. C The C–N bond is formed by 2sp2–2sp2 overlap. D All the carbon-nitrogen bonds have equal bond lengths. 6 Which of the following shows the correct shape and bond angle of the molecule given? molecule shape bond angle A OF2 bent 117o B BH3 trigonal pyramidal 120o C XeF4 tetrahedral 109.5o D SF6 octahedral 90o 7 At 25 oC and 101 kPa, a 1.00 g sample of dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon and 0.03% carbon dioxide by volume. What is the average relative molecular mass of the air sample? A 14.67 B 24.52 C 28.95 D 30.26 8 Which of the following statements about an ideal gas is correct? A The total volume of the individual molecules is significant when compared to the volume of the container which the gas occupies. B An ideal gas can liquefy at low temperature and high pressure. C The gas molecules are in constant, random motion. D The gas molecules have no mass.

© Raffles Institution 2016 9647/01/S/16 [Turn Over 4 9 Sodium carbonate reacts with ethanoic acid according to the equation below. Na2CO3(s) + 2CH3COOH(aq)  2CH3COONa(aq) + H2O(l) + CO2(g) In an experiment to determine the enthalpy change of reaction, Hr, 7.5 g of solid sodium carbonate ( Mr = 106) was added to 50 cm3 of excess aqueous ethanoic acid. The temperature of the resultant solution was monitored at various time intervals and the following graph was obtained. time of mixing of reactants Given that the specific heat capacity of the solution is 4.18 J cm–3 K–1, what is the enthalpy change of reaction, Hr? A +27.5 kJ mol–1 B +29.5 kJ mol–1 C +31.6 kJ mol–1 D +34.0 kJ mol–1 Hr

© Raffles Institution 2016 9647/01/S/16 [Turn Over 5 10 The DNA double helix consists of two DNA strands held together by hydrogen bonding. When heated, the DNA double helix separates into two random -coil single strands. When cooled, the random coils reform the double helix. DNA double helix ⇌ 2 random coils Which of the following graphs corresponds to the forward process? A B C D 11 Use of the Data Booklet is relevant to this question. 1,10-phenanthroline (phen) is an organic compound that is used as a ligand in coordination chemistry. It forms complexes with metal ions such as Fe3+ and Fe2+. The redox equilibrium between [Fe(phen)3]3+ and [Fe(phen)3]2+ is shown below. [Fe(phen)3]3+ + e– ⇌ [Fe(phen)3]2+ E = 𝑥 V Aqueous chlorine oxidises [Fe(phen) 3]2+ to [Fe(phen) 3]3+, but both aqueous bromine and iodine do not. What could be the value of 𝑥? A –0.88 B –1.18 C +0.88 D +1.18 G / kJ mol–1 T / K 0 G / kJ mol–1 T / K 0 G / kJ mol–1 T / K 0 G / kJ mol–1 T / K 0

© Raffles Institution 2016 9647/01/S/16 [Turn Over 6 12 Use of the Data Booklet is relevant to this question. An electrochemical cell is set up as shown: Which statement about the e.m.f. of the above cell is correct? A The e.m.f. of the cell is +0.99 V. B Addition of water to the Cr2O72–/Cr3+ half-cell decreases the e.m.f. of the cell. C Addition of H+(aq) to the Cu2+/Cu half-cell decreases the e.m.f. of the cell. D Addition of excess NH3(aq) to the Cu2+/Cu half-cell decreases the e.m.f. of the cell. 13 The two-step mechanism for the reaction 2X(g) + Y(g)  X2Y(g) is shown below. Step 1: X(g) + Y(g)  XY(g) (slow) Step 2: XY(g) + X(g)  X2Y(g) (fast) Which of the following is the rate equation for the reaction? A rate = k[X]2 B rate = k[X][Y] C rate = k[XY][X] D rate = k[X]2[Y] [Cr2O72–] = [Cr3+] = [H+] = 0.1 mol dm–3 [Cu2+] = 0.1 mol dm–3 salt bridge V Cu Pt T = 298 K

© Raffles Institution 2016 9647/01/S/16 [Turn Over 7 14 Ethanoic acid dissociates in aqueous solution as follows, where α is the degree of dissociation. CH3CO2H(aq) ⇌ CH3CO2–(aq) + H+(aq) 1 – α α α Which of the following statements is correct? A The Ka, in terms of α and initial concentration C, is α α 2C 1 . B pH decreases with decreasing concentration of ethanoic acid. C Ka increases with increasing concentration of ethanoic acid. D α does not change with the concentration of ethanoic acid. 15 The solubility product, Ksp, of magnesium hydroxide at 25 ºC is X. The solubility of magnesium hydroxide at 25 ºC is S. Which of the following statements is correct at 25 ºC? A The pH of a saturated solution of magnesium hydroxide is 14 + lg(2X)1/3. B The solubility of magnesium hydroxide in a solution of magnesium chloride is larger than S. C When solid sodium hydroxide is dissolved in a saturated solution of magnesium hydroxide, Ksp of magnesium hydroxide becomes smaller than X. D The Ksp of barium hydroxide is smaller than X. 16 Which property of the Period 3 elements, from Na to C l, increases consistently across the period? A enthalpy change of atomisation B number of unpaired electrons C electronegativity D atomic radius

© Raffles Institution 2016 9647/01/S/16 [Turn Over 8 17 Use of the