NJC H2 CHEM P1 Question Paper Prelim

1 NJC Preliminary Examination 9647/01/14 [Turn Over NATIONAL JUNIOR COLLEGE SH2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 9647/01 Thu 18 Sep 2014 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, subject class and registration number on the Answer Sheet in the spaces provided unless this has been done for you. There are 40 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 paper consists of 18 printed pages.

2 NJC Preliminary Examination 9647/01/14 Section A For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 Tin(IV) iodide can be prepared by refluxing 0.04 moles of tin with 0.03 moles of iodine dissolved in 50 cm3 of tetratchloromethane (boiling point: 77 oC). Sn + 2I2  SnI4 Orange crystals of the product are obtained by filtering the hot reaction mixture and then cooling the filtrate. Which of the following would indicate that the reaction is complete? A The boiling point of the reaction mixture is 77 oC. B No tin remains in the reaction flask. C Crystallisation occurs in the boiling solvent. D No more purple vapour is observed in the reaction vessel. 2 When an excess of K I was added to 5.0 cm 3 of a 0.400 mol dm 3 solution of AO4 3, 8.00 cm 3 of 0.500 mol dm -3 of Na 2S2O3 is required to react completely with the iodine liberated. What is the final oxidation state of A? A 3 B +1 C +2 D +3 3 Which equation corresponds to the third ionisation energy of titanium (Ti)? A Ti(g)  Ti3+(g) + 3e B Ti2+(s)  Ti3+(g) + e C Ti2+(g)  Ti3+(g) + e D Ti3+(g) + e  Ti2+(g) 4 A 1.0 dm3 sample of gas is heated from 27 °C to 54 °C under constant pressure. What will be the new volume of the gas at 54 °C? A 0.5 dm 3 B 0.9 dm3 C 1.1 dm3 D 2.0 dm3

3 NJC Preliminary Examination 9647/01/14 [Turn Over 5 The following graphs show the ideal gas relationship for 2 different ideal gases. Gas P has twice the amount of particles as gas Q. Which graph is correct? A B C D T p V 0 Q P T pV 0 Q P T V p 0 P Q p pV T 0 Q P

4 NJC Preliminary Examination 9647/01/14 6 Three carboncarbon bonds are labelled in the diagram. x y z Which bond is made up of an sp2sp3 overlap? A y only B z only C x and y only D x, y and z 7 Which of the following species has a bond angle of 120 around the central atom? A NC l3 B N3  C BBr3 D H3O+ 8 Enthalpy changes for the following reactions can be determined experimentally: N2(g) + 3H2(g)  2NH3(g) Hrxn = 93 kJ mol1 H2(g) + ½O2(g)  H2O ( l ) Hrxn = 242 kJ mol1 4NH3(g) + 5O2(g)  4NO(g) + 6H2O(l) Hrxn = 906 kJ mol1 What is the enthalpy change of formation of NO(g)? A + 90 kJ mol1 B +180 kJ mol1 C +360 kJ mol1 D +1270 kJ mol1 9 61.8 kJ of energy is required to vaporise 320 g of liquid bromine at its boiling point of 59 C. What is the entropy change of vaporisation for bromine at 59 C? A +0.093 kJ mol1 K1 B +0.186 kJ mol1 K1 C +0.523 kJ mol1 K1 D +1.050 kJ mol1 K1

NJC Prelim 10 The f A mi equil i incre What A 11 The t H2C2 Whi c A B C D inary Examin following re ixture of p o ibrium at a ased to 1.9 t is the num 1.9 titration curv O4, and 0.2 ch statemen Methyl ora of H2C2O4. The volu m There are The result added. nation action is us owdered c o a constant atm. merical value B 3 ve below sh 20 mol dm3 nt is correct? ange canno . me of H2C2O equal amou ant solution pH 0 sed industria H2O(g) + oal and st e temperatur e of the equ 3.24 hows the re 3 aqueous s ? ot be used a O4 used in th unts of HC2 n formed ha A 10 5 9647/01/ ally to produ C(s) eam at a re of 500 uilibrium con C 8.1 eaction betw sodium hydr as an indic a his titration i 2O4  and C2 as more H+ 20 A /14 uce a comb H2(g) + CO pressure o K. At equi nstant, Kp, a D ween a solu roxide. ator in a tit r is 40 cm3. O4 2 presen than OH w bustible gas O(g) f 1 atm w a librium, th e at 500 K? D 81 tion of 0.10 ration to ver nt at point A when 20 cm Volume of [ from coal. as allowe d e total pre s 0 mol dm3 w rify the co n A. m3 of NaOH f NaOH/ cm [Turn Over d to reach ssure had weak acid, ncentration has been m3 r

6 NJC Preliminary Examination 9647/01/14 12 Which statement is not a correct description of a strong monoprotic acid? A It can have a higher pH than a weak acid. B It has a relatively high electrical conductivity in dilute solution. C It requires the same volume of alkali for complete neutralisation compared to a weak monoprotic acid of the same concentration. D It forms an acidic buffer when 0.1 mole of sodium hydroxide is added to 0.2 mole of a strong monoprotic acid. 13 Hydrogen peroxide reacts with acidified iodide ions liberating iodine according to the equation below: H 2O2(aq) + 2H+(aq) + 2I(aq)  I2(aq) + 2H2O(l) The kinetics of this reaction were investigated and it was found to have the following rate equation: rate = k[H2O2][I] Two series of experiments were conducted giving rise to Graph A and Graph B. The concentrations of reagents used for both experiments were as follows: [H 2O2] = 0.1 mol dm–3, [I–] = 0.1 mol dm–3, [H+] = 0.01 mol dm–3 Graph A Graph B rate of reaction y x time Which combination shows the correct labelling of the x-axis for Graph A and y-axis for Graph B? x-axis for Graph A y-axis for Graph B A [I–][H+] / mol2 dm–6 [H2O2] / mol dm–3 B [H2O2][I–] / mol2 dm–6 [H+] / mol dm–3 C [H2O2] / mol dm–3 [H+] / mol dm–3 D [I–] / mol dm–3 [H2O2] / mol dm–3

7 NJC Preliminary Examination 9647/01/14 [Turn Over 14 Use of the Data Booklet is relevant to this question. When a solution of sulfuric acid is electrolysed, gas J and gas K are produced at the cathode and the anode respectively in the molar ratio 2:1. In another experiment, the same quantity of electricity is used to electrolyse a saturated sodium chloride solution and a gas L is evolved at the anode. What is the molar ratio of J : K : L? A 2:1:1 B 2:1:2 C 4:2:1 D 4:2:3 15 The diagram below is an experimental set-up by a student to purify a piece of impure copper. Which statement is correct? A The student should place the impure copper as electrode Z. B The blue Cu(NO 3)2 solution fades during the process of purification of copper. C The change in mass