MJC H2 CHEM P1 w answers

1 Class Reg Number Candidate Name ____________________________ MERIDIAN JUNIOR COLLEGE JC 2 Preliminary Examination Higher 2 ____________________________________________________________________________ CHEMISTRY 9647/01 Paper 1 Multiple-Choice Questions 26 September 2014 1 hour Additional Materials: Data Booklet and OMR answer sheet ____________________________________________________________________________ INSTRUCTIONS TO CANDIDATES Write your name, class and register number in the spaces provided at the top of this page. There are forty questions in this sec tion. 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 OMR answer sheet. Read very carefully the instructions on the OMR answer sheet. You are advised to fill in the OMR Answer Sheet as you go along; no additional time will be given for the transfer of answers once the examination has ended. This document consists of 16 printed pages (including 1 blank page). Use of OMR Answer Sheet Ensure you have written your name, class register number and class on the OMR Answer Sheet. Use a 2B pencil to shade your answers on the OMR sheet; erase any mistakes cleanly. Multiple shaded answers to a question will not be accepted. For shading of class register number on the OMR sheet, please follow the given examples: If your register number is 1, then shade 01 in the index number column. If your register number is 21, then shade 21 in the index number column. Calculator Model / No.

2 Section A For each question there are four possible answers, A, B, C and D. Choose the one you consider to be correct. 1 A 0.70 g impure sample of ammonium hydrogen sulfate, NH 4HSO4, is titrated with 0.200 mol dm–3 sodium hydroxide. 24.80 cm3 of aqueous sodium hydroxide is required for complete reaction. (Mr of NH4HSO4 = 115) What is the percentage purity of the sample? A 40.7% B 61.1% C 81.5% D 98.3% 2 20.00 cm 3 of 0.0200 mol dm –3 bromate(V), BrO3 –, was found to react completely with 80.00 cm3 of 0.0100 mol dm–3 hydroxylamine, NH2OH. BrO3 - ions are reduced as follows: BrO3 - + 6e + 6H+ → Br- + 3H2O Which of the following could be the half -equation for the oxidation of hydroxylamine ? A NH2OH → ½ N2O + 2H+ + ½ H2O + 2e B NH2OH + H2O → NO2 - + 5H+ + 4e C NH2OH → NO + 3H+ + 3e D NH2OH + 2H2O → NO3 - + 7H+ + 6e 3 Which of the particles would, on losing an electron, have a half -filled set of p orbitals? A N+ B O– C P– D Cl2+ 4 At 1.5 atm and 27 oC, 1 mole of gas E occupies a volume of 16.7 dm 3 while 1 mole of gas F occupies a volume of 2 0.0 dm3. Which one of the following gives a possible explanation for the observation? A Gas E could be He while gas F could be CO2. B Gas E could be NH3 while gas F could be H2. C Gases E and F are ideal. D Gases E and F have intermolecular van der Waals’ forces of attraction. Comment [A1]: A to D on one line

3 [Turn over 5 A student used the apparatus below to heat a can containing 300 g of water. The following data were recorded: Mass of propan-1-ol burnt = m g Change in temperature of water = ΔT oC You are given that: Relative molecular mass of propan-1-ol = 60.0 Enthalpy change of combustion of propan-1-ol = 2021 kJ mol−1 Specific heat capacity of water = c J g−1 K−1 What is the efficiency of this heating process? A (300 + m) x 2021 x 1000 x 100%c x T x 60.0 B m x c x T x 60.0 x 100%300 x 2021 x 1000  C 300 x c x T x 60.0 x 100%m x 2021  D 300 x c x T x 60.0 x 100%m x 2021 x 1000  thermometer can containing 300 g of water burner containing propan-1-ol Comment [A2]: Change mass to 200

4 [Turn over 6 The reaction between ammonia gas and hydrogen chloride is often used in schools to teach the concept of diffusion. A typical setup, where ammonia and hydrogen chloride gas are introduced on the opposite ends of a glass tube, is shown below. An equilibrium reaction can be established at a fixed temperature, where the dense white fumes formed are ammonium chloride. NH3(g) + HCl(g) NH4Cl(s) At T °C, when equimolar amounts of ammonia and hydrogen chloride were used, the Kp value of this equilibrium is found to be 1. Which of the following statements is true? A Increasing the partial pressure of either gas would cause K p to increase to a value that is greater than 1. B The Kp value of the equilibrium, NH4Cl (s) NH3 (g) + HCl (g), is 1. C The partial pressure of each gas at equilibrium is 0.50 atm. D There would be no change in the equilibrium position if the partial pressure of each gas was doubled at the same time. 7 Hypochlorous acid, HClO (pKa = 7.46), and chlorous acid, HC lO2 (pKa = 1.46), are examples of oxoacids related to the element chlorine. A solution was formed by mixing equal volumes of hypochlorous acid and chlorous acid, each made up separately to the same concentration. Which of the following statements about the species present in the resulting solution is likely to be true?? A [H+] < [HClO] < [HClO2] B [H+] < [HClO] = [HClO2] C [H+] < [HClO2] < [HClO] D [H+] = [HClO2] < [HClO] Comment [A3]: Change order of ABCD

5 [Turn over 8 The standard electrode potential for the following electrode reaction is +1.69 V. Pb4+(aq) + 2e– Pb2+(aq) Which of the following may be deduced from this information? A Lead(II) compounds can act as oxidising agents. B Lead(IV) ion is a strong reducing agent. C Lead is more stable in the +2 than in the +4 oxidation state. D Lead electrode is the positive electrode when connected to the standard hydrogen electrode half-cell. 9 A student set up the cell as shown. The following values for the cell potential were determined as a change was continuously made. Reading number Cell potential / V 1 +0.480 2 +0.300 3 +0.250 4 +0.130 5 +0.064 What continuous change in the tin half-cell could produce these results? A Add NaOH (aq) to the solution to form insoluble Sn(OH)2. B Decrease the surface area of the salt bridge immersed in the solution. C Increase the concentration of Sn2+(aq) in the solution. D Increase the surface area of copper electrode immersed in the solution. salt bridge V copper tin Sn2+ (aq) / 1 mol dm–3 Cu2+ (aq) / 1 mol dm–3 Comment [A4]: rephrase

6 [Turn over 10 The circuit shown in the diagram was set up. Which electrode reactions will occur on closing the switch? anode reaction cathode reaction A Hydrogen is evolved. Copper dissolves preferentially. B Zinc dissolves preferentially. Hydrogen is evolved. C Copper and zinc both dissolve. Hydrogen is evolved. D Oxygen is evolved. Copper and zinc both dissolve. 11 G, H and J are three elements found in Period 3 of the Periodic Table. Among the elements in Period 3,  the melting point of G is the highest.  the electrical conductivity of H is the highest.  the melting point of the oxides of J is the highest. Which of the following elements is not represented by G, H or J? A Na B Mg C Al D Si 12 In each of the following pairs, one mole of each oxide is reacted separately with aqueous sodium hydroxide. Which of the following pair of oxides shows that each oxide requires a different number of moles of sodium hydroxide for complete reaction? A P4O6 and P4O10 B SO2 and SO3 C Al2O3 and SO2 D BeO and Al2O3 electrode of brass (an alloy of copper and zinc) electrode of platinum switch dilute sulfuric acid

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