ACJC Prelim 2016 (all papers & soln)

1 © ACJC 2016 9647/01/Prelim/2016 [Turn over CHEMISTRY Preliminary Examination CHEMISTRY 9647/01 Higher 2 Paper 1 Multiple Choice 29 August 2016 1 hour Additional Materials: Multiple Choice Answer She et Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluids. Write your name, index number and tutorial class on the Answer Sheet in the spaces provided unless this has been done for you. 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 17 printed pages and 1 blank page. 9647/01/Prelim/16 2016 [Turn over 1

2 9647/01/Prelim/2016 [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 3.00 g of an impure sample of calcium carbonate was heated strongly until there was no change in mass. 200 cm3 of carbon dioxide, measured at room conditions, was obtained. What is the percentage purity of calcium carbonate? A 27.8 % B 29.8 % C 30.4 % D 35.8 % 2 Use of the Data Booklet is relevant to this question. Which underlined element in the following species has the +6 oxidation number? A ReOCl4 B H2P2O72– C TiCl4 D SbCl52– 3 Use of the Data Booklet is relevant to this question. Deuterium, D1 2 , is an isotope of hydrogen. Which of the following species has more electrons than protons, and more neutrons than protons? A D3O+ B ND4+ C OD– D AlD4– 4 In which of the following pairs does the first compound have a higher melting point than the second compound? first compound second compound A Mg3N2 Al2O3 B NH2OH H2O C CH3OCH3 (CH3)2NH D 2

3 9647/01/Prelim/2016 [Turn over 5 Which of the following bonds is not present in the following molecule? escitalopram A a σ bond formed by sp3–sp2 overlap between two C atoms B a σ bond formed by sp–sp overlap between C and N atoms C a σ bond formed by sp2–sp2 overlap between two C atoms D a σ bond formed by sp3–sp2 overlap between C and N atoms 6 Which of the following sets of compounds and ions is arranged in increasing bond angles? A NO2+ < CO32– < SO42– B IF4– < N2O4 < N3– C ICl2– < H2S < NO2 D SCl2 < C2H2 < CH2Cl2 7 0.50 g of a volatile liquid was placed in a syringe with a frictionless piston. The syringe was slowly warmed up till 91.0 oC at atmospheric pressure. The volume occupied in the syringe was 200.0 cm3 when all the liquid was vaporised. Assuming the vapour behaves as an ideal gas, what is the relative molecular mass of the liquid? A 18.7 B 74.9 C 93.5 D 149.8 3

4 9647/01/Prelim/2016 [Turn over 8 The enthalpy change when solid calcium chloride dissolves in water is –120 kJ mol –1. 250 g of water is placed in an insulated cup containing 11.1 g of calcium chloride. If the solution has the same specific heat capacity as liquid water, what is the rise in temperature of the solution? A 11.1 × 120 250 × 4.18 K B 11.1 × 120 × 103 111 × 250 × 4.18 K C 250 × 4.18 11.1 × 120 × 103 K D 11.1 × 120 111 × 250 × 4.18 K 9 Use of the Data Booklet is relevant to this question. The standard half-cells of four metals Mg, P, Q and R and their respective cations in solution were connected in pairs and the potential difference recorded. The results obtained are as shown. positive electrode negative electrode e.m.f. /V P Mg +1.60 Q Mg +2.22 Q R +2.55 Which of the following is the decreasing order of reducing power for the four metals? A R > Mg > P > Q B R > Mg > Q > P C Q > P > Mg > R D P > Q > Mg > R 10 Which of the following statements is always true for a chemical reaction that has reached chemical equilibrium? A The yield of the product(s) is greater than 50%. B The rate of the forward reaction is greater than the backward reaction. C The amounts of reactants and products do not change. D Both forward and backward reactions have stopped. 4

5 9647/01/Prelim/2016 [Turn over 11 The graph shows the change in pH when 0.10 mol dm–3 acid is gradually added to V cm3 of 0.10 mol dm–3 alkali. Which of the following combinations could have given these results? V alkali acid A 10 Sr(OH)2 CH3CO2H B 20 Ba(OH)2 HCl C 10 Ca(OH)2 H2SO4 D 20 NaOH HO2C–CO2H 12 Nitrogen oxide reacts with hydrogen gas as shown in the equation below. 2NO(g) + 2H2(g) N2(g) + 2H2O(g) The reaction wa s determined to be second order with respect to NO and first order with respect to H2. In an experiment, 2.0 mol dm –3 of excess NO was used to react with H 2, the concentration of H2 decreased to 6.25% of its original value in 24 minutes. How many minutes will it take for the concentration of H2 to decrease to 6.25% of its original value if the experiment was repeated using an excess of 4.0 mol dm–3 of NO? A 1.5 B 4.5 C 6.0 D 9.0 5

6 9647/01/Prelim/2016 [Turn over 13 Figure 1 shows the melting points of eight consecutive elements whereas Figure 2 shows the third ionisation energies of another set o f eight consecutive elements, inclusive of element Z in Figure 1. Which of the options in Figure 2 correspond to element Z in Figure 1? Figure 1 Figure 2 14 An equimolar amount of MgCl2, PC l5 and KCl were separately added to three beakers, each containing 50 cm3 of water. Which option correctly shows the resultant solutions arranged in increasing pH? A MgCl2, PCl5, KCl B PCl5, MgCl2, KCl C KCl, MgCl2, PCl5 D PCl5, KCl, MgCl2 15 Which of the following properties would not be expected for Group II elements or their compounds? A Barium sulfate has a higher temperature of decomposition than magnesium sulfate. B Barium oxide in water produces a solution which reacts with dilute hydrochloric acid to give a solution with a pH of approximately 7. C Beryllium forms compounds with the least covalent character. D Upon heating the nitrates of Group II elements, the volume of nitrogen dioxide evolved is four times as great as the volume of oxygen. elements elements Z A B C D third IE / kJ mol–1 melting point / OC 6

7 9647/01/Prelim/2016 [Turn over 16 Interhalogen compounds contain atoms of two or more different halogens. The interhalogen ICl was reacted with excess aqueous sodium hydroxide for a period of time. What is the relative proportion of each ion present in the solution after this reaction? Cl– I– IO– IO3– A 1 1 0 0 B 1 0 1 0 C 1 2 3 1 D 3 2 0 1 17 Which statement about hydrogen halides is incorrect? A The acidity of hydrogen halides increases down the group. B The reducing power of hydrogen halides increases down the group. C The halogens, with the exception of fluorine, react with hydrogen to form hydrogen halides which have permanent dipole – permanent dipole interactions. D The thermal stability of hydrogen halides increases down the group due to a larger electron cloud that is more polarisable. 18 Use of the Data Booklet is relevant to this question. Which of the following is not true about the first row transition metals and their compounds? A Fe(CN)63− does not oxidise I−. B Fe2(CO3)3 can be prepared by reacting FeCl3(aq) with Na2CO3(aq). C On addition of H2O2(aq) to hot acidified K2Cr2O7(aq), a green solution is formed. D On addition of Co(NO3)3 to water, a gas that relights a glowing splint is produced. 7

8 9647/01/Prelim/2016 [Turn over 19 Aklavinone is a tetracycline antibiotic. aklavinone Which combination of the number of chiral centres and of the number of sp 2 and sp 3 hybridised carbon atoms does it possess? numbe