TJC H2 Chem 2012 Prelim P1 QP

1 CHEMISTRY 9647/01 Paper 1 Multiple Choice Wednesday 19th September 2012 1 hour Candidates answer on separate paper. Additional materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, Civics Group and index number 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. This document consists of 17 printed pages and 1 blank page 9647/01/TJC Prelim 2012 [Turn over

2 9647/01/TJC Prelim 2012 [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 If a mixture of 0.4 g hydrogen and 9.6 g oxygen is exploded, wha t will be the volume of the remaining gas at room temperature and pressure? A 0.60 dm3 B 1.20 dm3 C 2.40 dm3 D 4.80 dm3 2 Which of the following contains two isoelectronic species? A NH4+ and BH3 B NH4+ and CH4 C BF3 and NH3 D PF5 and BF4- 3 For a given mass of an ideal gas, which of the following graphs display a different shape from the rest? A PV against V (at constant T) B V/T against T (at constant P) C 1/density against T (at constant P) D PV against P (at constant T) 4 25.0 cm3 of 0.0200 mol dm-3 of yellow FA1 solution reacts with x g of zinc and the latter is oxidised to Zn2+. The resulting solution required 15.0 cm3 of 0.0200 mol dm-3 of acidified KMnO4 to restore its original colour. Find x. A 0.0196 g B 0.0218 g C 0.0327 g D 0.0491 g

3 9647/01/TJC Prelim 2012 [Turn over 5 An aqueous sample containing the following anions is analysed. Cl− CO32− SO42− In which order should the reagents be added to determine the amount of chloride in the sample? [If a precipitate is formed, filtration process is carried out before the addition of the next reagent to the filtrate.] Reagent 1 R eagent 2 Reagent 3 A AgNO3 HNO3 Ba(NO3)2 B HNO3 Pb(NO3)2 AgNO3 C HNO3 Ba(NO3)2 AgNO3 D Ba(NO3)2 NH3 AgNO3 6 The successive ionisation energies (IE) of two elements X and Y, are given below: IE / kJ mol-1 1st 2 nd 3 rd 4 th 5 th 6 th 7 th 8 th X 786 1580 3230 4360 16000 20000 23600 29100 Y 1251 2298 3822 5158 6542 9330 11000 33604 The c ompound formed when X and Y combine is most likely to be A i onic, with formula X2Y B ionic, with formula XY2 C covalent, with formula XY4 D covalent, with formula X2Y5

4 9647/01/TJC Prelim 2012 [Turn over 7 The reaction between phosphorus and hydrogen can result in the formati on of phosphine as shown: P4(s) + 6H2(g) 4PH3(g) The graph shows the change in concentration of hydrogen for this reaction in which the system was disturbed after four hours. Which of the following could explain the change in the hydrogen concentration at time, t = 4 hours? A The volume of the reaction vessel was decreased. B A catalyst was added. C The pressure on the reaction mixture was decreased. D More phosphorus was added. Concentration of H2(g) / mol dm-3 Time / hours

5 9647/01/TJC Prelim 2012 [Turn over 8 If compound A is heated, it decomposes according to the equation: 2A(g) B(g) + C(g) The following diagram shows the progress of the reaction. What is the equilibrium constant for the reaction? A 0.8 B 2.0 C 4.0 D 10.0 9 In a blast furnace, carbon or carbon monoxide can be used to reduce iron(III) oxide. Fe2O3(s) + C(s) → 2Fe(s) + CO2(g) ∆H = +234 kJ mol−1 Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g) ∆H = −24.8 kJ mol−1 Carbon monoxide can be formed by the following reaction. C(s) + CO2(g) → 2CO(g) ∆H1 What is the value of ∆H1? A +86.3 kJ mol−1 B +139.5 kJ mol−1 C +172.5 kJ mol−1 D +258.8 kJ mol−1 10 Which of the following reactions shows a positive change in entropy? [Assume that all measurements are taken at 298 K and 1 atm pressure.] A N2O(g) à N2(g) + ½O2(g) B Fe(s) + S(s) à FeS(s) C Ca(s) + ½O2(g) à CaO(s) D C3H6(g) + H2(g) à C3H8(g) Concentration / mol dm-3 2 3 2 3 B A Time / hours

6 9647/01/TJC Prelim 2012 [Turn over 11 Car manufacturers are developin g engines that use H 2 as a fuel. Approximately 5% of industrial hydrogen is produced by electrolysis of water. How many coulombs are needed to produce 1.02 ´ 106 mol of H2 gas? A 1.02 ´ 106 C B 9.84 ´ 1010 C C 1.97 ´ 1011 C D 1.97 ´ 1014 C 12 Ethyl ethanoate undergoes a slow acid -catalysed hydrolysis in water where the concentration of acid in the solution remains constant. H+ CH3CO2CH2CH3 + H2O ® CH3CO2H + CH3CH2OH The rate equation is found to be rate = k[CH 3CO2CH2CH3][H+] When 0.1 mol dm -3 of HCl is reacted with 0.2 mol dm -3 of ethyl ethanoate, the half-life was found to be 62 min. Another reaction was carried out with 0.2 mol dm -3 of HCl and 0.2 mol dm -3 of ethyl ethanoate. How long does it take for the concentration of ethyl ethanoate to fall to 0.025 mol dm-3? A 31 min B 62 min C 93 min D 124 min 13 25 cm 3 of 0.1 mol dm -3 monobasic acid X is titrated with 25 cm 3 of 0.2 mol dm -3 NaOH. The end point cannot be detected using screened methyl orange. Which of the following is not correct? A The solution acts as a buffer when 12.50 cm3 of NaOH has been added. B Initial pH of the solution is more than 1.00. C pH of the equivalence point is more than 7. D Acid X is a weak acid.

7 9647/01/TJC Prelim 2012 [Turn over 14 A 100 cm 3 solution consists of 0.20 mol dm -3 MgCl2 and 0.10 mol dm -3 CuCl2. A solution of sodium hydroxide is added to the mixture. Mg(OH) 2 starts precipitating when 40 cm3 of sodium hydroxide has been added. The solubility product values of Mg(OH) 2 and Cu(OH)2 are 6.3 ´ 10-10 and 2.2 ´ 10-20 respectively. What is the concentration, in mol dm -3, of Cu 2+ in the solution when Mg(OH) 2 just precipitates? A 4.99 ´ 10-12 B 6.98 ´ 10-12 C 6.60 ´ 10-5 D 7.14 ´ 10-2 15 Which of the following graphs shows the correct trend in the physical property of the period 3 elements? A B C D

8 9647/01/TJC Prelim 2012 [Turn over 16 When a white solid W reacts with concentrated H2SO4, the products include pungent- smelling gases and a dark brown sol ution containing a yellow precipitate. When aqueous sodium thiosulfate is added, the yellow precipitate remains but the dark brown colour disappears. What is W? A NaNO2 B KI C MgCl2 D Ag2CO3 17 Whi ch statement is true about the first row transition metals or their compounds? A [Ni(C2O4)2(CN)2]4- has a coordination number of 4. B Yellow CrO42- is oxidised to orange Cr2O72- in an acidic medium. C Fe3+ is more stable in acidic than in alkaline medium. D Fe2(CO3)3 cannot be prepared by reacting FeCl3(aq) with Na2CO3(aq). 18 Tr ansition metals like nickel are used in the manufacture of margarine. Which of the following statements best explains the role of transition metals in this use? A Transition metals have very high melting points b ecause both 3d and 4s electrons are involved in forming strong metallic bond. B Transiti