PJC H2 CHEM P1 (With Answers)

PIONEER JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION HIGHER 2 CANDIDATE NAME CT INDEX GROUP NUMBER CHEMISTRY 9647/01 Paper 1 Multiple Choice 26 September 2014 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, CT group and index number in the spaces at the top of this page and on the Answer Sheet in the spaces provided. Do not use staples, paper clips, highlighters, glue or correction fluid. There are forty questions in 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. 1 3

2 © PJC 2014 9647/01/JC2 Prelim/2014 Section A For each question, there ar e four possible answers labelled A, B, C and D. Choose the one you consider to be correct. 1 Use of the Data Booklet is relevant to this question. How many molecules are present in 1 cm3 of methane gas under room conditions? A 1 x 24000 6.02 x 1023 B 1 x 6.02 x 1023 24000 C 6.02 x 1023 x 24000 1 x 1000 D 1 x 6.02 x 1023 x 16 2 Use of the Data Booklet is relevant to this question. Sodium percarbonate, (Na 2CO3)x.y(H2O2), is an oxidising agent in some home and laundry cleaning products. 5.0 cm 3 of 0.200 mol dm 3 sodium percarbonate releases 48.0 cm 3 of carbon dioxide at room conditions on reaction with excess hydrochloric acid. An identical sample, on titration with 0.100 mol dm 3 acidified KMnO4, requires 12.0 cm3 before the first pink colour appears. What is the ratio x : y? A 1 : 3 B 2 : 3 C 3 : 2 D 4 : 3 3 When iron is reacted with aqueous iron(III) ions, iron(II) ions are formed. Assuming the reaction goes to completion, how many moles of Fe and Fe 3+(aq) would result in a solution containing only Fe 2+(aq) once the reaction had taken place? No. of moles of Fe No. of moles of Fe3+(aq) A 1 2 B 1 3 C 1 5 D 2 3

3 © PJC 2014 9647/01/JC2 Prelim/2014 4 Use of the Data Booklet is relevant to this question. What do the ions 36S2 and 37Cl have in common? A Both ions have an outer electronic configuration 2s2 2p6. B Both ions have more electrons than neutrons. C Both ions have 20 neutrons in their nuclei. D Both ions contain the same number of nucleons in their nuclei. 5 The shapes of three species, E, F and G are bent, square planar and T -shaped respectively. What could E, F and G be? E F G A CS2 BrF4  BH3 B NO2 XeF4 BrCl3 C H2O PCl4 + XeF3 + D H2O SF4 ICl3 6 An ideal gas obeys the general gas equation pV = nRT. Which of the following statements is correct? A The volume of a given mass of an ideal gas is doubled if the temperature is increases from 50 oC to 100 oC B For a given mass of an ideal gas, the pressure is proportional to its volume at constant temperature. C One mole of any ideal gas occupies 22.4 dm3 at 25 oC and 1 atm. D The density of an ideal gas at c onstant pressure is inversely propo rtional to its temperature.

4 © PJC 2014 9647/01/JC2 Prelim/2014 7 Use of the Data Booklet is relevant to this question. In an experiment to determine the enthalpy change of solution of ammonium nitrate, 10.00 g of solid ammonium nitrate ( Mr = 80.0) was added to 50 g of water . The temperature of the resultant solution moni tored at various time intervals and the following graph was obtained. time of mixing of reactants What is the enthalpy change of solution of ammonium nitrate? A +15.5 kJ mol–1 B +16.7 kJ mol–1 C −15.5 kJ mol–1 D −16.7 kJ mol–1

5 © PJC 2014 9647/01/JC2 Prelim/2014 8 In a blast furnace, carbon or carbon monoxide can be used to reduce iron(III) oxide. 2Fe2O3(s) + 3C(s) → 4Fe(s) + 3CO2(g) ∆H = +468 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 in kJ mol−1? A +258.8 B +172.5 C +139.5 D +86.3 9 A student investigated the kinetics of th e reaction between 1.00 mol dm –3 potassium iodide and 0.0500 mol dm–3 sodium peroxodisulfate. S2O8 2(aq) + 2I(aq) → 2SO4 2(aq) + I2(aq) The two reactants were mixed in the presence of a known amount of sodium thiosulfate and a few drops of starch. The time taken for an intense blue colour to be observed was recorded. Experiment number Volume used / cm3 Time / s KI Na2S2O8 H2O 1 10.0 5.0 25.0 170 2 15.0 5.0 20.0 113 3 15.0 10.0 15.0 56.5 4 20.0 20.0 0.0 z What is the value of z? A 11 B 21 C 85 D 1360 10 A Cu2+|Cu half-cell was connected to a Ag +|Ag half-cell through a salt bridge that contained aqueous K2SO4. The voltmeter registered a reading of +0.44 V. Which could be a reason for the discrepancy between the calculated Ecell and the observed value of +0.44 V? A The piece of copper in the Cu2+|Cu half-cell was too small. B The piece of silver in the Ag+|Ag half-cell was too large. C The concentration of Cu2+ was larger than 1 mol dm-3. D The concentration of Ag+ was larger than 1 mol dm-3.

6 © PJC 2014 9647/01/JC2 Prelim/2014 11 5.00 g of silver was deposited when electricity was passed through silver nitrate solution. The same quantity of electricity also liberated 3.02 g of an element H from a solution containing an unknown cation, Hj+. It is known that the relative atomic mass of H is 197, what is the value of j? A 1 B 2 C 3 D 5 12 A chemist carried out a series of experiments involving the following equilibrium. H2(g) + I2(g) ⇌ 2HI(g); H = +54 kJ mol–1 He performed the first set of experiment a t a temperature T1 K and found that the equilibrium constant, Kc has a value of 64. In the second set of experiment, he added 1.0 mol of H 2 and 1.0 mol of I2 into a 1 dm 3 flask, at a temperature of T2 K. When equilibrium was established, the flask was found to contain 1.2 mol of HI. What is the relationship between T1 and T2? A T1 = T2 B T1 > T2 C T1 < T2 D The relationship cannot be determined based on his experiments alone. 13 Solutions M, N, O and P contain a strong acid, a weak acid, a salt of weak acid and a strong base, but not necessarily in the same order. The concentration and pH of each solution are shown below. (You may assume that all acids and bases react in a 1 : 1 ratio.) Which of the following statements is not correct? Solution Concentration in mol dm–3 pH M 1.0 2.4 N 1.0 9.4 O 0.010 12.0 P 0.001 3.0 A M contains a weak acid while P contains a strong acid. B Mixing 10 cm3 of M and 500 cm3 of O produces a buffer solution. C Mixing 10 cm3 of O and 500 cm3 of P produces a buffer solution. D Mixing 100 cm3 of M and 100 cm3 of N produces a buffer solution.

7 © PJC 2014 9647/01/JC2 Prelim/2014 14 The pH change when 0.100 mol dm –3 CH3CO2H is added dropwise to 10.0 cm 3 of 0.100 mol dm–3 KOH(aq) is given in the graph below. At which point on the graph does pH = p Ka, where Ka is the acid dissociation constant of the weak acid? 15 The solubility product of a substance is S. If the concentration of the cation in a saturated solution is found to be 1 59()4 S , what could be the substance? A CaCl2 B Ca3(PO4)2 C Al(OH)3 D Al2(SO4)3 16 Element Q is in P eriod 3