RI H2 Chem 2013 Prelim P1 QP

© Raffles Institution 2013 9647/01/S/13 [Turn Over RAFFLES INSTITUTION 2013 YEAR 6 PRELIMINARY EXAMINATION HIGHER 2 CHEMISTRY 9647/01 Paper 1 Multiple Choice 27 September 2013 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 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 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 23 printed pages. 157

2 © Raffles Institution 2013 9647/01/S/13 [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 Which expression correctly defines the term relative atomic mass of an element? A the mass of 1 mole of atoms of an element divided by 6.02 × 1023 B the mass of 1 atom of an element relative to the mass of of a 12C atom C the average mass of 1 atom of an element relative to the mass of of a 12C atom D the average mass of 1 mole of atoms of an element relative to the mass of a 12C atom 2 Use of the Data Booklet is relevant to this question. Potassium manganate( VII), KMnO 4, reacts with sodium cyanide, NaCN, in a molar ratio of 2:3 to form manganese(IV) oxide, MnO2. Which of the following would be the carbon-containing product in this reaction? A B C D 3 For which of the following pairs does species I have a smaller bond angle than species II? I II A NO3 – NO2 – B SF6 ClF3 C XeF4 BrF5 D BrO3 – ClO3 – 158

3 © Raffles Institution 2013 9647/01/S/13 [Turn Over 4 To produce decaffeinated coffee, pure liquid CO 2 is sometimes used to extract caffeine from coffee beans. caffeine It was discovered that the solubility of caffeine greatly increased when a mixture of ethanol and liquid CO2 (ethanolCO2 mixture) was used. Which interaction best explains why caffeine is more soluble in the ethanol CO2 mixture as compared to liquid CO2? A hydrogen bonding B dative covalent bonding C permanent dipole – permanent dipole interactions D instantaneous dipole – induced dipole interactions 5 For a fixed mass of an ideal gas, which of the following graphs does not have the same general shape as the rest? ( ρ = density of the gas; M = molar mass of gas) A P  against T B PV against T M C P against ρ T D T P against V 6 When 1 mole of carbon dioxide gas solidifies as dry ice, 25.2 kJ of heat energy is evolved. The sublimation temperature of carbon dioxide is 78.5 C. What is the entropy change when 132 g of carbon dioxide gas solidifies at this temperature? A 389 J K1 B 130 J K1 C +130 J K 1 D +3 89 J K1 159

4 © Raffles Institution 2013 9647/01/S/13 [Turn Over 7 Given the following thermochemical data, calculate the standard enthalpy change of the reaction, Hr . CH3C CCH3 (g) CH2 CHCH CH2 (g) Standard enthalpy change of combustion of CH3CCCH3(g) = –2577 kJ mol–1 Standard enthalpy change of combustion of carbon = –394 kJ mol–1 Standard enthalpy change of combustion of hydrogen = –286 kJ mol–1 Standard enthalpy change of formation of CH2=CHCH=CH2(g) = +110 kJ mol–1 A 253 kJ mol1 B 33 kJ mol1 C +33 kJ mol 1 D + 253 kJ mol1 8 Pentaamminechlorocobalt( III) ions and hydroxide ions react as follows: [Co(NH3)5Cl]2+(aq) + OH–(aq) [Co(NH3)5OH]2+(aq) + Cl–(aq) The variation for the initial rate of reaction with the concentrations of the reactants was investigated in three experiments. experiment [Co(NH3)5Cl2+] / mol dm–3 [OH–] / mol dm–3 initial rate / mol dm–3 s–1 1 0.20 0.30 0.364 2 0.40 0.30 0.727 3 0.10 0.45 0.273 Based on the above data, which of the following statements is correct? A The rate of reaction is pH dependent. B The overall order of the reaction is one. C The units of the rate constant are mol –2 dm6 s–1. D The activation energy of the reaction is lowered by using a concentrated alkali. Hr  160

5 © Raffles Institution 2013 9647/01/S/13 [Turn Over 9 The reaction between acidified K I and aqueous H2O2 involves the following steps: H 2O2 + I– H2O + OI– slow O I– + H+ HOI fast HOI + H+ + I– I2 + H2O fast Which graph would be obtained? A B C D 10 Methylamine, CH 3NH2, is a weak base. When 40 cm 3 of 0.10 mol dm –3 HCl is added to 20 cm 3 of 0.30 mol dm –3 CH3NH2, the pH of the resulting solution obtained is 10.5. Given Kw = 1.00 × 10–14 mol2 dm–6, what is the pKb of methylamine, CH3NH2? A 3.20 B 3.50 C 5.20 D 10.5 -3[reactant] / mol dm time/s0 rate [H+] time [H2O2] [I] rate time [H2O2] [I] [H+] 161

6 © Raffles Institution 2013 9647/01/S/13 [Turn Over 11 A solution consists of 0.10 mol dm –3 MgSO4 and 0.10 mol dm–3 FeSO4. It is suggested that the metal ions can be separated as their hydroxides. At 298 K, the solubility product of Mg(OH) 2 is 7.1  10–12 mol 3 dm–9 and that of Fe(OH) 2 is 4.1  10–15 mol3 dm–9. What would be the pH of the resultant solution when maximum separation has occurred? A 7.05 B 8. 93 C 10.1 D 13.4 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 +1.35 V. B Addition of water to the Pb 4+/Pb2+ half cell increases the e.m.f of the cell. C Decreasing the mass of the copper electrode decreases the e.m.f of the cell. D Addition of excess aqueous ammonia to the Cu 2+/Cu cell increases the e.m.f of the cell. [Pb4+] = [Pb2+] = 0.1 mol dm–3 [Cu2+] = 0.1 mol dm–3 salt bridge V Cu Pt T = 298 K Cu2+ Pb2+ Pb4+ 162

7 © Raffles Institution 2013 9647/01/S/13 [Turn Over 13 Use of the Data Booklet is relevant to this question. A student carried out an experiment involving the electrolysis of aqueous copper( II) sulfate in Cell I and aqueous sulfuric acid in Cell II. 0.00417 mol es of copper was deposited at electrode B after electrolysis. Given that relative formula mass of A l2O3 is 102.0, what is the maximum mass of A l2O3 formed at electrode C? A 0.142 g B 0.426 g C 0.639 g D 0.851 g 14 Tetrachloromethane, CC l4, does not react with water under normal conditions, while silicon tetrachloride, SiC l4, is completely hydrolysed by water to give SiO2 and HCl. Which statement best explains the differences in reactivity between CCl4 and SiCl4? A The C Cl bond is stronger than the SiCl bond. B The Si Cl bond is more polar than the CCl bond. C Silicon possesses low –lying empty d orbitals but not carbon. D SiCl4 forms stronger van der Waals’ interactions with water than CCl4. A B C