PJC H2 Chemistry 2008 JC2 H2 Chemistry Prelim Paper 1 (with soln)

PIONEER JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION 2008 CHEMISTRY 9746/01 Higher 2 Paper 1 Multiple Choice 18 September 2008 1 h our Additional materials: Data Booklet Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Write your name, CT Group and index number on the answer sheet in the spaces provided unless this has already been done for you. There are forty questions in this paper. Answer all questions. For each question, there are four possible answers labelled 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 14 printed pages. [Turn Over

2 Section A For each question, there are four possible answers labelled A, B, C and D . Choose the one you consider to be correct. 1 25.0 cm 3 of 0.05 mol dm-3 KClO4(aq) required 50.0 cm3 of 0.20 mol dm-3 TiCl3 (aq) to reach end-point. Given that titanium( III) is oxidised to titanium( IV) in this reaction, which one of the following formulae correctly represents the reduction product of the ClO4 - ion? A Cl- B ClO2 - C ClO3 - D OCl- 2 Which of the following is not true about P3- ion? A It is very polarisable. B It is isoelectronic with argon. C Its p-orbitals are completely filled. D It is smaller than a phosphorus atom. 3 X and Y are elements with the following successive ionisation energies in kJ mol-1. X 580 1800 2700 11600 14800 18400 23300 Y 1310 3400 5300 7500 11300 13300 20300 What is the compound that is formed from element X and Y? A XY4 B X 2Y3 C X 3Y2 D X 4Y 4 In which of the following pairs is the bond angle of the second molecule / ion greater than that of the first? A NO 2 +, NO2 - B SO 4 2-, SO3 2- C BrF 3, ClF3 D PH 3, AsH3

3 5 A 2 g sample of hy drogen at temperature T and of volume V exerts a pressure p. Deuterium, H2 1 , is an isotope of hydrogen. Which of the following would also exert a pressure of p at the same temperature T? A a mixture of 1 g of hydrogen and 1 g of deuterium of total volume V B a mixture of 1 g of hydrogen and 2 g of deuterium of total volume V C a mixture of 1 g of hydrogen and 2 g of deuterium of total volume 2V D a mixture of 2 g of hydrogen and 2 g of deuterium of total volume 2V 6 The enthalpy change of formation of H 2S(g) and H2O(l) are -21 kJ mol-1 and - 286 kJ mol-1 respectively and the enthalpy change of vaporisation of water is +41 kJ mol-1. What is the enthalpy change of r eaction for the following process? H2S(g) + ½O2(g) → H2O(g) + S(s) A -224 kJ mol -1. B -266 kJ mol -1. C -306 kJ mol -1. D -348 kJ mol -1. 7 The lattice energies of rubidium fl uoride, RbF, and caesium chloride, CsC l, are -760 kJ mol-1 and -650 kJ mol-1, respectively. What is the lattice energy of caesium fluoride, CsF, likely to be? A -520 kJ mol -1 B -580 kJ mol -1 C -720 kJ mol -1 D -920 kJ mol -1 8 In an attempt to determine a value for Avogadro constant, a current I was passed for a time of t s into an aqueous solution of copper( II) sulphate using two copper electrodes of mass m 1 g each. At the end of the experiment, the mass of the copper anode was found to be m2 g. The charge on one electron is e C. What is the value for Avogadro constant, L? A ) ( t I . 2 12 5 63 m m eL − × × ××= B ) ( t I . 1 2 5 63 m m eL − × × ×= C tI. ) ( × × − × ×= 5 63 2 2 1m m eL D I t. ) ( × × − ×= 5 63 1 2m m eL

4 9 A voltaic cell is made up of the Mg2+/Mg half-cell and the Fe3+/Fe2+ half-cell. Which one of the following statements is correct? A Addition of water to the Fe 3+/Fe2+ half-cell decreases the e.m.f. of the cell. B Addition of aqueous sodium hydroxide to the Mg 2+/Mg half-cell increases the e.m.f. of the cell. C Increasing the temperature has no effect on the e.m.f. of the cell. D The Mg2+/ Mg half-cell is the positive electrode. 10 Gaseous hydrogen iodide dissociates on heat ing to set up the equilibrium shown below. 2HI(g) ⇌ H2(g) + I2(g) A quantity of gaseous hydrogen iodide was heated at constant pressure p at a certain temperature. The equilibrium partial pressure of HI (g) was found to be p7 1 . What is the value of the equilibrium constant, K p, at this temperature? A B C 9 D 36 7 6 7 9 11 What is the final pH of the solution fo rmed by mixing equal volumes of two sulphuric acid solutions, one with pH 1.0 and the other with pH 3.0? A 0.7 B 1.0 C 1.3 D 2.0 12 Which of the following statements about acids, bases and salts is correct? A 10 cm 3 of 0.10 mol dm -3 of ethanoic acid reacts with 5 cm 3 of 0.10 mol dm -3 sodium hydroxide to produce an alkaline buffer. B 10 cm 3 of 0.10 mol dm -3 of hydrochloric acid reacts with 5 cm 3 of 0.10 mol dm -3 aqueous ammonia produces an acidic buffer. C 0.10 mol dm -3 of aqueous sodium ethanoate has higher pH than 0.10 mol dm -3 of aqueous ammonium chloride. D 0.10 mol dm -3 of ethanoic acid has hi gher pH than 0.10 mol dm -3 of aqueous sodium ethanoate.

5 13 Which statement explains the observations that magnesium hydroxide dissolves in aqueous ammonium chloride, but not in aqueous sodium chloride? A Ammonium hydroxide is first formed, and then acts through a common ion effect. B The ammonium ion changes the solubility product of Mg(OH) 2. C NH 4Cl dissociates less fully than NaCl. D The NH4 + ion acts as an acid. 14 The following is the reaction for compound XY, XY(g) → X(g) + Y(g) If the rate constant for the reaction is 5.78 x 10 -3 s-1, what is the time taken for the concentration of a sample of XY to decrease from 1.80 mol dm-3 to 0.225 mol dm-3. A 120 s B 240 s C 360 s D 480 s 15 Using a colorimeter, the following reaction is studied by finding the time taken for a coloured reactant, P, to decolourise. The reaction is catalysed by Y. P + Q R + S Y The following results are obtained: Experiment Vol of P added / cm3 Vol of Q added / cm3 Vol of Y added/ cm3 Vol of H2O added/ cm3 Time taken / s 1 10 20 10 10 20 2 10 10 10 20 40 3 10 20 5 15 40 4 5 20 10 15 10 What is the rate equation for the reaction? A Rate = k[Q][Y] B Rate = k[P][Y] C Rate = k[P][Q] D Rate = k[P][Q][Y] 16 Which of the following sets contains an ox ide with giant molecular structure and a chloride with simple molecular structure? A MgO MgC l2 B A l2O3 A lCl3 C SiO 2 SiCl 4 D P4O10 PCl 5

6 17 Magnesium oxide is used in the making of the lining of blast furnace. It is extracted from seawater as follows. Aqueous calcium hydroxide is added to seawater. Ca(OH) 2(aq) + MgCl2(aq) → Mg(OH)2(s) + CaCl2(aq) The magnesium hydroxide is then filtered off and roasted. Which of the following comparisons bet ween calcium and magnesium explains why magnesium hydroxide forms? A Magnesium is lower than calcium in the reactivity series. B The solubility product for Mg(OH) 2 is lower tha