TJC Prelim P1 Qn

1 2017 TJC H2 Chemistry Preliminary Examination [Turn Over CHEMISTRY 9729/01 Paper 1 Multiple Choice 15th September 2017 1 hour Additional materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. There are thirty 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. The use of an approved scientific calculator is expected, where appropriate. This document consists of 13 printed pages. Write your name and Civics Group Write and shade your index number

2 2017 TJC H2 Chemistry Preliminary Examination [Turn Over 1 The reaction between aluminium powder and anhydrous barium nitrate is used as the propellant in some fireworks. Nitrogen gas is one of the products formed. Which volume of nitrogen, measured under room conditions, is produced when 1 g of anhydrous barium nitrate reacts with an excess of aluminium? A 86.9 cm3 B 91.8 cm3 C 174 cm3 D 184 cm3 2 Which statements about relative molecular mass are correct? 1 It is the mass of one mole of the molecule. 2 It is the ratio of the average mass of a molecule to the mass of a 12C atom. 3 It is the sum of the relative atomic masses of all the atoms within the molecule. A 1, 2 and 3 B 2 and 3 only C 2 only D 3 only 3 The Claus process recovers sulfur from the gaseous hydrogen sulfide found in raw natural gas and from the crude oil refinery by-product gases. reaction I 2H2S(g) + 3O2(g) → 2H2O(l) + 2SO2(g) reaction II 2H2S(g) + SO2(g) → 2H2O(l) + 3S(s) Which statement about the Claus process is correct? A SO2 is a reducing agent. B SO2 behaves as a catalyst. C H2S is oxidised in the reaction. D Reaction II is a disproportionation reaction. 4 A stream of gaseous, doubly-charged calcium ions was passed between 2 oppositely charged plates. Analysis of the deflection shows that these ions deflected at an angle of 20.0°. Under the same electric field, an unknown gaseous ion X+ is deflected at an angle of 5.08°. What is the atomic number of X? A 34 B 45 C 46 D 79

3 2017 TJC H2 Chemistry Preliminary Examination [Turn Over 5 Which of the following species do not have all atoms that lie on the same plane? A CH2CH2 B I3- C XeF4 D BeCl42- 6 In which pair of compounds does the first compound have higher boiling point than the second compound? A HI, HF B MgO, NaCl C CH4, SiH4 D trans-C2H2Cl2, cis-C2H2Cl2 7 A sample of m g of an organic compound is vaporised in a gas syringe and occupies V cm3 at T K and p atm. What is the relative molecular mass of the compound? A m x 24000 x T p x V x 293 B m x 24000 x (T+293) p x V x 273 C m x 24000 x 293 x p V x T D m x 24000 x 293 x p V x (T+273)

4 2017 TJC H2 Chemistry Preliminary Examination [Turn Over 8 An autocatalytic reaction is one wher eby the products catalyses the reaction. One such reaction is the reaction between ethanedioate and manganate(VII) anions. 2MnO4- + 5C2O42- + 16H+  2Mn2+ + 10CO2 + 8H2O Which of the following graphs would be obtained for an autocatalytic reaction? A B C D 9 Molecular bromine, Br 2 reacts with methanoic acid, HCOOH slowly in an open beaker to produce aqueous hydrogen bromide and carbon dioxide gas. Br2(aq) + HCOOH(aq)  2HBr(aq) + CO2(g) Which of the following methods is not suitable for studying the kinetics of this reaction? A Measuring the conductivity of the solution over time. B Measuring the change in pressure of the reaction over time. C Measuring the change in colour intensity of the mixture over time. D Measuring the changes of pH of the solution over time.

5 2017 TJC H2 Chemistry Preliminary Examination [Turn Over 10 When bromine vapourises at 58.8oC, 30.9 kJ mol-1 of heat was required. What is the entropy change when 32 g of bromine is vapourised? A -18.6 J K-1 B +18.6 J K-1 C -93.1 J K-1 D +93.1 J K-1 11 Compound E is a hydrocarbon. When 0.47 g of E was completely burnt in air, the heat produced raised the temperature of 200 g of water by 26.4 °C. Given that the standard enthalpy change of combustion of E is –3290 kJ mol–1, which of the following could be E? 1 CH2=CHCH2CH3 2 (CH3)2C=CHCH3 3 C5H10 A 1 only B 3 only C 1 and 2 D 2 and 3 12 Two equilibria are shown below. reaction I X2(g) + 1 2 Y2(g) ⇌ X2Y(g) reaction II 2X2Y(g) ⇌ 2X2(g) + Y2(g) The numerical value of Kc for reaction I is 2. Under the same conditions, what is the numerical value of Kc for reaction II? A 1 2 B 1 √2 C 1 4 D 2

6 2017 TJC H2 Chemistry Preliminary Examination [Turn Over 13 Consider the following equilibrium system: P(s) + Q(g) R(g) + 3S(s) H = +ve 0.500 mol each of P and Q were placed in a 1 dm3 container. At equilibrium, 0.100 mol of R was formed. Which of the following statement is not correct? A The value of Kc is 0.25. B Kp increases with increasing temperature. C Increasing the pressure will not affect the equilibrium. D Adding P causes the position of equilibrium to shift to the right. 14 Which of the following mixtures does not act as a buffer solution? A 10 cm3 of 1 mol dm-3 HCl and 5 cm3 of 1 mol dm-3 Mg(CH3CH2COO)2 B 20 cm3 of 1 mol dm-3 Na2CO3 and 20 cm3 of 1 mol dm-3 NaHCO3 C 20 cm3 of 1 mol dm-3 HCl and 20 cm3 of 2 mol dm-3 CH3CH2NH2 D 10 cm3 of 1 mol dm-3 NaOH and 20 cm3 of 1 mol dm-3 NH4Cl 15 Iron pipes are used to transport natural gas to cities. Corrosion occurs when water droplets sit on the outer surface of the iron pipes. Miniature galvanic cells are created, with regions such as those shown below, that act as anodes and cathodes. Which of the following is incorrect? A The reaction at the cathode is O2 + 2H2O + 4e- → 4OH-. B The reaction at the anode is Fe → Fe2+ + 2e-. C The corrosion of iron is inhibited at low pH. D Corrosion can be prevented by connecting it to a magnesium bar buried in the ground. cathode anode

7 2017 TJC H2 Chemistry Preliminary Examination [Turn Over 16 Copper minerals often contain magnesium and silver as impurities. An impure copper rod is purified by electrolysis using a constant current. After 1 hour, the mass of one electrode decreased by 19.0 g while the mass of the other electrode increased by 17.8 g. Which of the following statements is correct? 1 The decreased in mass is due to the oxidation of copper, magnesium and silver. 2 The increase in mass is due to copper being formed. 3 Doubling the mass of the impure copper rod under the same set of operating conditions double the mass of the copper deposited. A 2 only B 1 and 2 C 1 and 3 D 2 and 3 17 Consider the oxides of period 3 elem