PJC 2015 H1 CHEM P1 QP ANS Prelims

PIONEER JUNIOR COLLEGE 2015 JC2 PRELIMINARY EXAMINATION HIGHER 1 CHEMISTRY 8872/01 Paper 1 25 September 2015 Additional Materials: Data Booklet Multiple Choice Answer Sheet 50 minutes READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name and index number on the Answer Sheet in th e spaces provided unless this has been done for you. 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 penci l 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 13 printed pages Name: Index No.: CT Group: 14

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 Which of the following has the greatest mass? A 6 x 1023 molecules of hydrogen gas B 3 moles of nitrogen molecules C 1.2 x 1024 iron atoms D 3 x 1023 copper(II) ions 2 A sample of 10 dm 3 of polluted air, measured at room temperature and pressure, is passed through limewater so that all the carbon dioxide present is precipitated as calcium carbonate. The mass of calcium carbonate formed is 0.05 g. What is the percentage, by volume, of carbon dioxide in the air sample? [Ar of C, 12.0; O, 16.0; Ca, 40.1] A 0.03 % B 0.05 % C 0.12 % D 0.6 % 3 Gaseous particle B has a proton number n and a charge of +1. Gaseous particle C has a proton number of (n+1) and is isoelectronic with B. B and C have the same number of neutrons. Which of the following statements incorrectly describes B and C? A The charge of B is half that of C. B B has a larger ionic radius than C. C B requires less energy than C when a further electron is removed from each particle. D B has a higher charge density than C. 4 Which of the following molecules/ions has the smallest bond angle? A AlH4‾ B SO3 2‾ C XeF2 D SF2

3 5 Blu-Tack is a reusable adhesive that consists of a synthetic long chain hydrocarbon, and it is able to stick on to many surfaces, such as ceramic tiles and glass. What is the likely attraction between Blu-Tack and glass surfaces? A van der Waal’s forces B covalent bond C hydrogen bond D ionic bond 6 The table shows the enthalpy change of neutralisation, H, for the various a cids and bases. acid base H / kJ mol–1 sulfuric acid sodium hydroxide –57.0 P sodium hydroxide Less exothermic than –57.0 sulfuric acid Q Less exothermic than –57.0 R potassium hydroxide –57.0 What are the likely identities of P, Q and R? P Q R A hydrochloric acid lithium hydroxide nitric acid B phosphoric acid ammonia ethanoic acid C nitric acid lithium hydroxide hydrochloric acid D ethanoic acid ammonia nitric acid 7 Phosphine reacts with hydrogen iodide to form phosphonium iodide by the following reaction: PH3(g) + HI(g)  PH4I(s) Ho rxn = −102 kJmol−1 Given that Ho f for PH3(g) = +5.4 kJ mol −1 and Ho f for HI(g) = +26.5 kJ mol −1, what is the enthalpy change of formation of phosphonium iodide? A −56.5 kJ mol−1 B −70.1 kJ mol−1 C −123.1 kJ mol−1 D −133.9 kJ mol−1

4 8 Two moles of compound P were placed in a vessel. The compound P was partly decomposed by heating. A dynamic equilibrium between P, Q and R was established. At equilibrium, x mol of R were present and the total number of moles present was (2 + x). What is the equation for this equilibrium? A P ⇌ 2Q + R B 2P ⇌ 2Q + R C 2P ⇌ Q + R D 2P ⇌ Q + 2R 9 Swimming pool water can be kept free of harmful bacteria by adding aqueous sodium chlorate(I), NaOC l. This reacts with water to produce HOC l molecules which kill bacteria. OCl–(aq) + H2O(l) ⇌ OH–(aq) + HOCl(aq) In bright sunshine, the OCl– ion is broken down by ultra-violet light. OCl–(aq) Cl–(aq) + ½O2(g) Which method would maintain the highest concentration of HOCl(aq)? A acidify the pool water B add a solution of chloride ions C add a solution of hydroxide ions D bubble air through the water 10 What is the pH o f the resulting solution when equal volumes of aqueous Ba(OH) 2 at pH 10 and 12 are mixed ? A 11.0 B 11.7 C 12.3 D 13.0 uv light

5 11 An enzyme, found i n the stomach, operates at maximum efficiency when in an aqueous solution buffered at pH 5. Which combination of substances, when dissolved in 10 dm 3 of water, would give the necessary buffer solution? A 2 mol of CH3CO2H and 1 mol of NaOH B 2 mol of NaOH and 1 mol of CH3CO2H C 1 mol of HCl and 1 mol of CH3CO2Na D 2 mol of NH3 and 1 mol of CH3CO2NH4 12 Hydrogen peroxide reacts with acidified iodide ions liberating iodine according to the equation below: H2O2(aq) + 2H+(aq) + 2I(aq)  I2(aq) + 2H2O(l) The kinetics of this reaction were investigated and it was found to have the following rate equation: rate = k[H2O2][I] Two series of experiments were conducted giving rise to Graph A and Graph B. Graph A Graph B rate of reaction y x time Which combination shows the correct labelling of the x -axis for Graph A and y-axis for Graph B? x-axis for Graph A y-axis for Graph B A [I–][H+] / mol2 dm–6 [H2O2] / mol dm–3 B [H2O2][I–] / mol2 dm–6 [H+] / mol dm–3 C [H2O2] / mol dm–3 [H+] / mol dm–3 D [I–] / mol dm–3 [H2O2] / mol dm–3

6 13 Consecutive elements X, Y, Z are in the third period of the Periodic Table. Element Y has the highest first ionisation energy and the lowest melting point. What could be the identities of X, Y and Z? X Y Z A magnesium aluminium silicon B aluminium silicon phosphorus C sodium magnesium aluminium D silicon phosphorus sulfur 14 An element H forms an oxide of high melting point which is insoluble in water. The chloride of H is solid at room temperature, has a low melting point and boiling point and dissolves in water forming an acidic solution. What element is H? A magnesium B aluminium C silicon D phosphorus 15 How many isomers, including cyclic compounds , are there with the molecular formula C4H8? A 4 B 5 C 6 D 7 16 Which line on the graph shows the relatio nship between the number of carbon atoms in an alkane and the number of moles of oxygen gas needed for complete combustion of the alkane? 1

7 17 The diagram represents a section of a catalytic converter on the exhaust system for a car. Harmful gases are converted into carbon dioxide, nitrogen and water vapour. Which of the following statements is incorrect? A Platinum and rhodium catalyse redox reactions. B Carbon monoxide an d nitrogen oxide r eact to form carbo n dioxide and nitrogen. C Carbon monoxide reacts with hydrocarbons to give carbon dioxide and water. D Oxides of nitrogen react with hydrocarbons to give carbon dioxide, water and nitrogen. 18 An organic compound, on heating with an excess of hot c oncentrated acidified KMnO4(aq), produces CH3CH2COCH2CH2CO2H as one of the products. Which of the following shows the structure of the organic compound? A B C D CO hydrocarbons NOx CO2 H2O N2

8 19 Steroidogenesis is the biological pathway by which cholesterol is transformed into other biological ster