TJC H2 CHEM P1 QN Prelim

1 2015 TJC H2 Chemistry Preliminary Examinations [Turn over CHEMISTRY 9647/01 Paper 1 Multiple Choice 18th September 2015 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 forty 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 you r 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 21 printed pages. Write your name and Civics Group Write and shade your index number

2 2015 TJC H2 Chemistry Preliminary Examinations [Turn over Section A For each question, there are four possible answers, A, B, C and D . Choose the one you consider to be correct. 1 Incomplete combustion of y dm3 of butane, C 4H10, yielded a mixture of carbon dioxide and carbon monoxide in the ratio of 3:1, together with water vapour. What is the volume of oxygen consumed? A 5y dm3 C 9y dm3 B 6y dm3 D 12y dm3 2 0.005 mol of a metal oxide, Y2Ox, reacted exactly with 0.006 mol of acidified potassium manganate(VII) solution. The half-equation for the reduction of MnO4 – is shown below. MnO4 – + 8H+ + 5e–  Mn2+ + 4H2O Given that the oxidation state of Y in the product is +6, what is the value of x? A 1 C 3 B 2 D 4 3 Use of the Data Booklet is relevant to this question. Significant contributions to carbon dioxide levels in the atmosphere comes from the thermal decomposition of limestone (calcium carbonate) and the manufacture of cement and lime (calcium oxide). Cement works roast 1000 million tonnes of limestone per year and a further 200 million tonnes is roasted in kilns to make lime. What is the total annual mass output of carbon dioxide (in million tonnes) from these two processes? A 440 B 528 C 660 D 880 4 Which of the following species has three unpaired electrons? A Al B Ti3+ C Zn2+ D Cr3+

3 2015 TJC H2 Chemistry Preliminary Examinations [Turn over 5 Which of the following describes a phenomenon which cannot be explained by hydrogen bonding? A Ethanoic acid molecules form a dimer when dissolved in benzene. B Ice has a lower density than water at 0 oC. C The boiling point of alcohol increases with increasing molecular mass. D 2-nitrophenol has a lower boiling point than 4-nitrophenol. 6 Which plot clearly exhibits ideal gas behavior? A C B D T/K V/dm 3 P = 3 atm P = 1 atm T/K V/dm 3 P = 3 atm P = 1 atm T/K V/dm 3 P = 3 atm P = 1 atm T/K V/dm 3 P = 3 atm P = 1 atm T/oC V/dm 3 P = 3 atm P = 1 atm T/oC V/dm 3 P = 3 atm P = 1 atm T/K V/dm 3 P = 3 atm P = 1 atm T/K V/dm 3 P = 3 atm P = 1 atm

4 2015 TJC H2 Chemistry Preliminary Examinations [Turn over 7 Use of Data Booklet is relevant to this question. Propane burns exothermically in air as follows. CH3CH2CH3(g) + 5O2(g)  3CO2(g) + 4H2O(l) H = -2200 kJ mol-1 0.05 moles of propane from the burner was used to heat 0.9 dm 3 of water. It was found that the temperature of the water increased to 40 oC after three minutes at room conditions. What is the rate of heat loss to the surroundings in kJ min-1? A 17.9 kJ min-1 B 36.7 kJ min-1 C 53.6 kJ min-1 D 103 kJ min-1 8 Use of Data Booklet is relevant to this question. A cell involving aqueous potassium iodide and acidified sodium manganate(VII) is shown. Which of the following statements is true? A The e.m.f of the cell is -0.98 V. B The purple colour of iodine will become more intense over time. C The light bulb will be brighter when the concentration of MnO4 -(aq) increases. D The direction of electron flow will reverse whe n the MnO4 -/Mn2+ half-cell is replaced with a Cl2/Cl- half cell. Pt Pt 1 mol dm-3 MnO4 -(aq) 1 mol dm-3 Mn2+(aq) 1 mol dm-3 I-(aq) and I2 solid

5 2015 TJC H2 Chemistry Preliminary Examinations [Turn over 9 Use of Data Booklet is relevant to this question. In the commercial electrolysis of concentrated sodium chloride, the products are chlorine, hydrogen and sodium hydroxide. What is the maximum yield of each of these products when 58.5 kg of sodium chloride was electrolysed? Yield of chlorine /kg Yield of hydrogen /kg Yield of sodium hydroxide /kg A 35.5 1 40 B 35.5 2 80 C 71 1 40 D 71 2 80 10 The equilibrium, A 2(g) + 4 B(g) ⇌ 2AB2(g), has an equilibrium constant K c of 3.60. What will be the numerical val ue of the equilibrium constant for the following reaction at the same temperature? AB2(g) ⇌ ½ A2(g) + 2B(g) A 0.14 C 0.28 B 0.53 D 3.60

6 2015 TJC H2 Chemistry Preliminary Examinations [Turn over 11 Sulfur dioxide is converted to sulfur trioxide in the Contact process as shown by the equation below. 2SO2(g) + O2(g) ⇌ 2SO3 (g) To investigate the reaction, two experiments were conducted. Experiment 1: Quantities of SO2 and O 2 were placed in a sealed vessel and the reaction was allowed to proceed at a constant temperature. Experiment 2: The experiment was repeated at a different temperature using quantities of reactants same as experiment 1. The graph below shows the amount of SO2 present in the mixture. These results show that experiment 2 was conducted at a A higher temperature and the forward reaction is endothermic. B lower temperature and the forward reaction is endothermic. C higher temperature and the forward reaction is exothermic. D lower temperature and the forward reaction is exothermic. 12 Steam reforming process is the most common method for industrial production of hydrogen. CH4(g) + H2O(g) ⇌ CO(g) + 3H2(g) The value of K c is found to be 5.27 for this reaction when 0.65 mol of m ethane is mixed with 0.30 mol of steam in a 1 dm3 vessel. How many moles of steam must be added to the mixture to raise the equilibrium amount of hydrogen gas to 0.84 mol at the same temperature? A 0.030 C 0.085 B 0.065 D 0.090 Number of moles of SO2 time Experiment 2 Experiment 1

7 2015 TJC H2 Chemistry Preliminary Examinations [Turn over 13 The numerical value of solubility product of magnesium hydroxide is 1.8 x 10 -12. What is the solubility of magnesium hydroxide in a solution of sodium hydroxide at pH 12.5 and 25 °C? A 5.69 x 10-11 C 1.80 x 10-9 B 4.50 x 10-10 D 7.66 x 10-5 14 The graph below shows t he variation in the boiling points for eight consecutive elements in the Periodic Table, all with atomic number between 10 and 20. Which of the following statements is true? A Element A and barium are in the same group. B Element G has a smaller atomic radius than element H. C Element D has a lower first ionisation energy than element C. D The oxide of G dissolves in water to give an acidic solution. Atomic number A B C D E F G H Boiling point B A D C E H G F

8 2015 TJC H2 Chemistry Preliminary Examinations