SRJC H1 CHEM P1 QP

1 Turn Over] SERANGOON JUNIOR COLLEGE General Certificate of Education Advanced Level Higher 1 Candidate Name Class CHEMISTRY 8872/01 JC2 Preliminary Examination 28 Aug 2015 Paper 1 Multiple Choice 50 min Additional Materials: Data Booklet Optical Mark Sheet (OMS) READ THESE INSTRUCTIONS FIRST On the separate multiple choice OMS given, write your name, subject title and class in the spaces provided. Shade correctly your FIN/NRIC number. There are 30 questions in this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider c orrect and record your choice using a soft pencil on the separate OMS. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. You are advised to fill in the OMS as you go along; no additional time will be given for the transfer of answers once the examination has ended. Any rough working should be done in this question paper. This document consists of 13 printed pages.

2 Turn Over] Answer all questions 1 Oxides of nitrogen, NxOy, are air pollutants. In a reaction, 0.30 mol of NxOy is reacted with 30 dm 3 of hydrogen gas at room temperature and pressure and passed over a heated catalyst to produce ammonia and water as the only products . At the end of the reaction, 1.20 dm 3 of hydrogen gas remains . The ammonia produced required 0.300 mol of sulfuric acid for complete neutralisation. What is the molecular formula of the oxide? A NO B NO2 C N2O D N2O4 2 In an experiment, H 2S was reacted with 28.00 cm 3 of 0.250 mol dm 3 of an unknown arsenate species, H 3AsOx, in a strongly acidic medium to form a yellow solid of mass 0.225 g and ortho–arsenite, AsO3 3. Determine the oxidation state of As in H3AsOx. A +2 B +3 C +4 D +5 3 The ion E2+ has 86 electrons and 138 neutrons. Which of the following statements is true? A Element E is isoelectronic with radon. B The first ionisation energy of element E is higher than that of Sr. C The oxide of E formed is expected to have a higher melting point than SrO. D In an electric field, the ion E2+ will be deflected at a smaller angle than that of Sr2+.

3 Turn Over] 4 The second ionisation energies ( I.E.) of seven consecutive unknown elements F to L in Periods 2 and 3 of the Periodic Table are shown in a graphical plot below. Which unknown letter (F to L) is likely to represent the element nitrogen? A Element F B Element G C Element H D Element I 5 Lithium peroxide, Li 2O2, is synthesi sed by reacting lithium hydroxide with hydrogen peroxide. Which diagram correctly shows the bonding of the peroxide anion in Li2O2? Key: electron from the first oxygen atom electron from the second oxygen atom  electron from lithium atom A B C D F G H I J K L 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5 6 7 8 9 10 11 12 13 Second I.E./ kJ mol1 Proton Number x x x x x

4 Turn Over] 6 Which pair of compounds satisfies the following conditions? (i) The first compound has a larger bond angle than the second compound. (ii) The first compound is more polar than the second compound. First compound Second compound A ClO2 HCN B NF3 SeF6 C IF3 PH3 D BeCl2 N2H4 7 Which of the following has a positive ∆H value? A CH4(g) + 2O2(g)  CO2(g) + 2H2O(l) B NaOH(aq) + CH3COOH(aq)  CH3COO–Na+(aq) + H2O(l) C 2O(g)  O2(g) D Na(s)  Na(g) 8 The table shows the enthalpy change of neutralisation per mole of water formed, ∆H, for the following acids and bases. acid base ∆H /kJ mol-1 hydrochloric acid sodium hydroxide -57.0 P Sodium hydroxide -54.0 hydrochloric acid Q -52.0 nitric acid R -57.0 What are P, Q and R? P Q R A propanoic acid ammonia sodium hydroxide B propanoic acid potassium hydroxide ammonia C sulfuric acid ammonia potassium hydroxide D sulfuric acid sodium hydroxide ammonia

5 Turn Over] 9 The table shows some data on two acid-base indicators. Indicator pH range of colour change Colour change acid alkali thymolphthalein 9-10 colourless blue chlorphenol red 6-7 yellow red Which conclusion can be drawn about a solution in which thymolphthalein is colourless and chlorphenol red is red? A It is weakly acidic. B It is neutral. C It is weakly alkaline. D It is strongly alkaline. 10 Equal volumes of 0.050 moldm-3 of hydrochloric acid was mixed with 0.050 mol dm–3 of calcium hydroxide. Calculate the pH of the resulting solution. A 13.1 B 12.4 C 7.0 D 1.6 11 Serine protease (SP) is a biological catalyst which increases the rate of hydrolysis of amide bonds in proteins. Which graph represents the [serine proteases] to rate of reaction A B C D 0 [SP] rate 0 [SP] rate 0 [SP] rate 0 [SP] rate

6 Turn Over] 12 The Boltzman distribution curve shows the number of gas molecules have a particular kinetic energy at constant temperature, T1. What happens to the size of the areas labelled S, U and V if a higher temperature, T2 was used? S U V A increase increase decrease B increase decrease decrease C decrease increase increase D decrease decrease increase 13 Compound W decomposes upon heating according to the following equation: 2W(s) 2X (g) + Y(g) When 3.9 mol of W were put into a 1.0 dm 3 container and heated, the equilibrium mixture contained 0.8 mol of Y. What is the approximate numerical value of the equilibrium constant Kc? A 0.387 B 0.640 C 1.28 D 2.05 Number of gas molecules having a given energy Kinetic energy V U S T1

7 Turn Over] 14 Under which following sets of condition may result in the highest yield of C 6H12 at equilibrium for the following reaction C6H6(g) + 3H2(g) C6H12 (g) ∆H < 0 Temperature Pressure A High High B High Low C Low High D Low Low 15 Please use the following data for Question 15 and 16. The following graph shows the boiling points of eight consecutive elements from Periods 2 and 3 of the Periodic Table. Which of the following statement about the oxides of the elements is incorrect? A The oxide of (vi) is a giant molecule. B The oxide of (i) has a melting point of 1286oC. C (viii) can form an oxide with variable oxidation states. D The oxide of (vii) dissolves in water to give an acidic solution. 16 Which of the following statement about the chlorides of the elements is correct? A (iii) and (vi) form chlorides with high melting points. B The chloride of (vii) hydrolyses in water to give a basic solution. C The chloride of (iv) dissolves in water to give a slightly acidic solution. D (v) forms a chloride that is a good electrical conductor in the aqueous and molten state.

8 Turn Over] 17 Element Z has a melting point of 97.7°C. The oxide of element Z reacts with water to give an alkaline solution. However, its chloride dissolves in water to give a neutral solution. What is element Z? A sodium B aluminium C silicon D