PJC H2 CHEM P1

PIONEER JUNIOR COLLEGE, SINGAPORE JC2 PRELIMINARY EXAMINATIONS HIGHER 2 CHEMISTRY 9746/01 Paper 1 Multiple Choice 24 September 2009 1 hour 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. A calculator may be used. 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 A radioactive isotope of thallium, , is used to assess damage in heart muscles after a heart attack. lT201 81 Which statement about is correct? lT201 81 A The isotope has a nucleon number of 120. B The number of electrons in one atom of this isotope is 81. C The number of neutrons in one atom of this isotope is 201. D is an isotope of . lT201 82 lT201 81 2 Use of the Data Booklet is relevant to this question. Oxides of nitrogen are pollutant gases which are emitted from car exhausts. In urban traffic, when a car travels one kilometre, it releases 0.23 g of an oxide of nitrogen NaOb, which occupies 120 cm3 at room temperature and pressure. What are the values of a and b? A a = 1, b = 1 B a = 1, b = 2 C a = 2, b = 1 D a = 2, b = 4 3 Plastic bottles for ‘fizzy drinks’ are made from a polymer with C C H H E H H H n The ability of the polymer to prevent the escape of carbon dioxide through the wall of the bottle depends on the ability of the group E to form hydrogen bonds with the carbon dioxide in the drink. Which group E best prevents the loss of carbon dioxide? A Cl C CO 2CH3 B CN D OH © PJC 2009 9746/01/Prelim/S/09 [Turn over

3 4 Which one of the following graphs below shows the correct plot of pV against p for a fixed mass of ideal gas at two temperatures, T1 and T2, in which T1 > T2? A C p T2 T1 pV TpV 2 T1 p B D pV T2 T1 p T2 T1 pV p 5 The standard enthalpy changes of formation of HCl and HI are –92 kJ mol -1 and +26 kJ mol -1 respectively. Which statement is most important in explaining this difference? A The bond energy of H I is smaller than the bond energy of HCl. B The bond energy of I2 is smaller than the bond energy of Cl2. C Chlorine is more electronegative than iodine. D The activation energy for the H 2 / Cl2 reaction is much less than that for the H2 / I2 reaction. 6 Given the following enthalpy changes, P 4(s) + 6Cl2(g) → 4PCl3(l) ΔH = −1260 kJ mol−1 P 4(s) + 10Cl2(g) → 4PCl5(s) ΔH = −1820 kJ mol−1 What is the enthalpy change for the following reaction? PCl3(l) + Cl2(g) → PCl5(s) A − 140 kJ mol-1 C − 560 kJ mol-1 B − 193 kJ mol-1 D − 770 kJ mol-1 © PJC 2009 9746/01/Prelim/S/09 [Turn over

4 7 The standard electrode potential for the metals X and Y are given below. X2+ (aq) / X(s); E θ = -0.25 V Y+ (aq) / Y(s); E θ = +0.80 V The diagram of the cell made up of the above two half-cells is shown below. Which description is correct for this cell? Cathode Eθ cell Direction of electron flow Electrode at which positive ions enter the solution A X + 0.55 V X to Y X B X + 1.05 V Y to X Y C Y + 1.05 V X to Y X D Y + 0.55 V Y to X Y 8 During electrolysis under suitable conditions, 0.785 g of chromium is deposited on the cathode when 4370 C of electricity is passed into a chromium-containing electrolyte. Which of the following could have been the electrolyte? A CrCl 2 C K 2CrO3 B CrCl 3 D K2Cr2O7 9 The equilibrium constant, Kp, for the following reaction is 4.44 at a temperature, T oC. 2H I(g) H 2(g) + I2(g) A mixture containing an equal amount of H 2(g) and I2(g) at a total pressure of 1 atm is allowed to reach equilibrium at T oC in a vessel with constant volume. What is the partial pressure of H 2(g) at equilibrium at T oC? A 0.096 atm C 0.339 atm B 0.161 atm D 0.404 atm © PJC 2009 9746/01/Prelim/S/09 [Turn over

5 10 1 mol of propanoic acid is diluted at constant temperature to a volume V. Which one of the following diagrams shows how the acid dissociation constant, Ka, varies with V? A C Ka Ka B D V V V Ka Ka V 11 What is the pH value of a solution containing 0.10 mol dm -3 of aqueous NH3 and 0.10 mol dm-3 of aqueous (NH4)2SO4? (pKb of NH3 = 4.75) A 4.75 C 8.95 B 5.05 D 9.25 12 The solubility products of calcium fluoride and calcium carbonate are 4.0 x 10 -11 mol3 dm-9 and 8.7 x 10-9 mol2 dm-6 at 25 oC respectively. Which of the following statements is not true? A When calcium nitrate is added into a 1 dm3 solution containing 0.01 mol of fluoride and 0.01 mol of carbonate ions, calcium fluoride precipitates out first. B Calcium fluoride has a higher molar solubility than calcium carbonate C Addition of hydrochloric acid increases the solubility of calcium carbonate D Addition of sodium fluoride to a solution containing calcium fluoride decreases the solubility product of calcium fluoride. 13 Which of the following statements about the rate constant, k, of chemical reactions is not true? A The rate constant increases when a catalyst is used. B The rate constant remains the same if the concentration of reactants is increased. C The rate constant increases if the activation energy is increased D The rate constant can have different units. © PJC 2009 9746/01/Prelim/S/09 [Turn over

6 14 The kinetics of the reaction between H +(aq) and S2O3 2-(aq) can be investigated experimentally by varying the volumes of HCl(aq) and Na2S2O3(aq) used and determining the time taken, t, for the formation of sulphur to completely obscure the cross as shown in the diagram. S2O3 2-(aq) + 2H+(aq) → S(s) + SO2(g) + H2O(l) HCl(aq) + Na2S2O3(aq) beaker cross The table below shows the experimental results obtained. Volume used / cm3 Experiment 1.0 mol dm-3 HCl(aq) 0.040 mol dm-3 Na2S2O3(aq) H2O(l) t / s 1 10.0 5.0 25.0 170 2 15.0 5.0 20.0 170 3 15.0 10.0 15.0 85 4 20.0 20.0 0.0 f What is the value of f in Experiment 4? A 21 C 85 B 43 D 170 15 On adding G(aq) to H(aq), a brown mixture (white precipitate in brown solution) was obtained. On addition of J (aq), a white precipitate and a colourless solution were observed. On further addition of J(aq), the white precipitate dissolved. Which of the following could be G, H and J? G H J A CuSO4 KI Na2S2O3 B Fe2(SO4)3 NaOH KI C Fe2(SO4)3 NaNO 2 KI D ZnSO4 NaOH NH3 © PJC 2009 9746/01/Prelim/S/09 [Turn over

7 16 Use of the Data Booklet is relevant to this question. When 16.4 g of calcium nitrate is heated, what is the volume of gases produced, measured at room temperature and pressure? A 1.20 dm3 C 4.80 dm 3 B 2.40 dm 3 D 6.00 dm3 17 Which of the following is not true about Group II compounds? A The solubility of Group II sulphates decreases down the group. B The ease of thermal decomposition of Group II carbonates increases down the group. C Reactivity of Group II oxides with water