CJC H2 CHEM P1 QP Prelim

1 [Turn over CATHOLIC JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATIONS Higher 2 CHEMISTRY 9647/01 Paper 1 Multiple Choice Wednesday 3 September 2014 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write your name and HT group on the Answer Sheet in the spaces provided. Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. 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. The use of an approved scientific calculator is expected, where appropriate. This document consists of 18 printed pages and 0 blank page.

2 9647/01/CJC JC2 Preliminary Exam 2014 Section A 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 in soft pencil on the separate Answer Sheet provided. 1 Use of the Data Booklet is relevant to this question. Which one of the following has the same number of the stated partic le as atoms in 127 g of iodine at room conditions? A number of atoms in 79 g of gold B number of anions in 0.5 mol of barium chloride C number of ions in 1 mol of potassium bromide D number of molecules in 10 g of hydrogen fluoride 2 Use of the Data Booklet is relevant to this question. In polluted air, the white paint pigment in older oi l paintings forms lead(II) sulfide, PbS, that is black in colour. To restore the white colour, an oxidising agent, hydrogen peroxide, H2O2, is used. Given that 0.239 g of PbS requires 25 cm 3 of 0.160 mol dm –3 H2O2 for oxidation, what is the possible identity of the white paint pigment? A S8 B PbS2 C PbSO3 D PbSO4 3 Use of the Data Booklet is relevant to this question. Which one of the following specie s has more neutrons than electrons and more electrons than protons? A 37Cl– B 48Ti4+ C 79Br+ D 32S2-

3 9647/01/CJC JC2 Preliminary Exam 2014 [Turn over 4 In recent years, many scientists have been researching the potential of copper complexes as drugs in chemotherapy due to their ability to inhibit cell proliferation and induce apoptosis in cells. An example of such a complex is shown below: Which one of the following best describes the bonds formed with Cu? Cu-N1 Cu-N2 A dative π B π ionic C ionic dative D σ π 5 What is the most likely bond angle of the sulfur atom in S,S-diphenylsulfilimine? A 90 B 107 C 109 D 120

4 9647/01/CJC JC2 Preliminary Exam 2014 6 Which graph correctly describes the behaviour of fixed masses of the ideal gases I and J, where I has a higher Mr than J? A B C D 7 Fe3+ and SCN- react in a closed system to give the complex, [Fe(SCN)]2+, which is blood-red in colour. Fe3+(aq) + SCN-(aq) ⇌ [Fe(SCN)]2+(aq) ΔH < 0 Which one of the following changes will result in the solution turning pale red? A Increase the concentration of SCN-. B Decrease the pressure of the system. C Decrease the temperature of the system. D Add a small amount of dilute NaOH(aq) to the resulting mixture. 1/V P Constant T I J T PV Constant P J I 1/T P Constant V I J Constant T I J PV P

5 9647/01/CJC JC2 Preliminary Exam 2014 [Turn over 8 Solid NaC l dissolves in water to give Na +(aq) and C l-(aq) ions under standard conditions of 298 K, 1 atm. NaCl(s) → Na+(aq) + Cl-(aq) Na+(g) + Cl-(g) → NaCl (s) ΔHlatt o = -781 kJ mol-1 Na+(g) → Na+(aq) ΔHhyd o = -390 kJ mol-1 Cl-(g) → Cl-(aq) ΔHhyd o = -381 kJ mol-1 What is the standard enthalpy change of solution, ΔHsol o, for the above reaction? A -10 kJ mol-1 B +10 kJ mol-1 C -20 kJ mol-1 D +20 kJ mol-1 9 What is the pH of the resulting solution when 2.50 g of NH4Cl is dissolved in 250 cm3 of 0.100 mol dm-3 NH3(aq)? [Kb of NH3 = 1.8 × 10-5 mol dm-3] A 5.01 B 8.99 C 9.53 D 14.0 10 Equal volumes of aqueous K I and 0.200 mol dm -3 of Pb(NO 3)2 are mixed together to precipitate PbI2. Given that the K sp value of PbI2 is 8.70 × 10 -9 mol3 dm-9, which one of the following could have been the initial concentration of KI? A 8.70 × 10-8 mol dm-3 B 2.95 × 10-4 mol dm-3 C 5.90 × 10-4 mol dm-3 D 1.50 × 10-2 mol dm-3 11 Two electrode potentials are given below: Co3+ + e- ⇌ Co2+ Eo = +1.82 V Sn4+ + 2e- ⇌ Sn2+ Eo = +0.15 V Which species is the strongest reducing agent? A Co2+ B Co3+ C Sn2+ D Sn4+

6 9647/01/CJC JC2 Preliminary Exam 2014 12 Use of the Data Booklet is relevant to this question. The cell shown in the diagram is set up under standard conditions where X and Y are platinum electrodes. Half-cell A Half-cell B Which one of the following statements is correct? A Addition of AgNO3(aq) to half-cell A will not affect Ecell o. B The voltmeter will show a reading of about +1.52 V. C The electrons will flow from X to Y through the voltmeter. D Y will be the negative electrode. 13 Hydrogen peroxide reacts with iodide ions in acidic solution as follows: H2O2(aq) + 2 H+(aq) + 2 I-(aq)  2 H2O(l) + I2(aq) The rate equation was found experimentally to be: rate = k[H2O2][I-]. Which mechanism is consistent with the kinetics of this reaction? A H2O2 + H+ → H2O + OH+ (fast) H+ + OH+ + 2 I– → H2O + I2 (slow) B 2 H+ + 2 I– → 2 HI (fast) 2 HI + H2O2 → I2 + 2 H2O (slow) C H2O2 + I– → H2O + IO– (slow) H+ + IO– → HIO (fast) HIO + H+ + I– → I2 + H2O (fast) D H2O2 + I– + H+ → H2O + HIO (fast) HIO + I– → I2 + OH– (slow) OH– + H+ → H2O (fast) Cl2(g) Cl–(aq) MnO4 -(aq), Mn2+(aq), H+(aq) X Y

7 9647/01/CJC JC2 Preliminary Exam 2014 [Turn over 14 The diagram shows the Boltzmann distribution of molecular energies of a gas at a given temperature. Which one of the following statements correctly describes what happens as temperature increases? A The activation energy of the reaction is lowered. B The maximum of the curve is displaced to the left. C The proportion of molecules with E < Emax increases. D The proportion of molecules with energies above any given value increases. 15 For the oxides of Period 3 elements (Na to P), which property decreases from Na 2O to P4O10? A covalent character B melting point C pH when mixed with water D solubility in aqueous alkali 16 Which property of strontium, a Group II element, and its compounds is correct? A Strontium does not burn in air. B Strontium does not react with steam. C Strontium hydroxide produces strontium oxide when heated strongly. D Strontium nitrate decomposes at a lower temperature than calcium nitrate. Fraction of molecules with energy, E Energy, E Emax

8 9647/01/CJC JC2 Preliminary Exam 2014 17 Which one of the following statements is most likely to be true for astatine, the element below iodine in Group VII of the Periodic Table? A Potassium astatide and hot dilute sulfuric acid react to form white fumes of hydrogen astatide. B Astatine and aqueous potassium chloride react to form aqueous potassium astatide and chlorine. C Sodium astatide and hot concentrated sulfuric acid react to form astatine. D Silver astatide and dilute aqueous ammonia react to form a solution of a soluble complex. 18 The hexa-aquairon(III) ion hydrolyses as shown below. [Fe(H2O)6]3+(aq) + H2O(l) ⇌ [Fe(H2O)5OH]2+(aq) + H3O+(aq) Which one of the following statements is corre