2021 YIJC Prelim P1 Qns

©YIJC [Turn Over YISHUN INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 1 CANDIDATE NAME CG INDEX NO CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 8873/01 16 September 2021 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid/tape. Write your name and class on the Answer Sheet in the 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 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 10 printed pages and 2 blank pages.

2 @YIJC [Turn Over 1 10 cm3 of a hydrocarbon CxHy was exploded with an excess of oxygen. There was a contraction of 30 cm 3. When the product was treated with a solution of potassium hydroxide, there was a further contraction of 40 cm3. What is the molecular formula of the hydrocarbon? [All gas volumes are measured at r.t.p.] A C4H8 B C4H10 C C3H6 D C3H8 2 Three organic molecules each have • three elements; • the composition, by mass, C, 54.5 %; H, 9.1 %. What could these molecules be? 1 CH3CH2CH2CO2H 2 OHCCH2CH2CH2OH 3 CH3CH=CHCH2SH A 1, 2 and 3 B 1 and 2 C 2 and 3 D 1 and 3 3 Use of the Data Booklet is relevant to this question. In which series of elements do the atoms have the same number of neutrons as protons? 1 4He, 12C, 24Mg 2 14N , 20Ne , 30P 3 28Si, 34S, 40Ca, A 1, 2 and 3 B 1 and 2 C 2 and 3 D 1 and 3 4 Which of the species in their gaseous state shown below will be deflected by the largest angle in an electric field? A 11B3+ B 4He2+ C 9Be2+ D 1H2

3 @YIJC [Turn Over 5 Which of the following shows the correct bond angles x, y and z for ethanoic acid as shown below? x y z A 90° 120° 109° B 109° 120° 105° C 109° 180° 109° D 90° 180° 105° 6 Consider the following four compounds. What is the order of increasing boiling point of the compounds? 1 CH3CH2CH2F 2 CH3CH2CH2OH 3 CH3CH2CH2CH3 4 (CH3)3CH A 1  2  4  3 B 3  4  1  2 C 4  3  1  2 D 4  3  2  1 7 The reaction of iodine with propanone in the presence of aqueous acid is zero order with respect to iodine. Which diagram represents the variation of [I2] with time? A B C D x C C O O H H H H y z

4 @YIJC [Turn Over 8 Lead is the final product formed by a series of changes in which the rate-determining step is the radioactive decay of uranium – 238. This radioactive decay is a first order reaction with a half-life of 4.5 x 109 years. How long would it take for a rock sample, originally lead -free, to contain a molar proportion of uranium to lead of 1 : 3? A 1.5 x 109 years B 2.25 x 109 years C 9.0 x 109 years D 13.5 x 109 years 9 An equilibrium is represented by the following equation. N2(g) + 3H2(g) 2NH3(g) ∆H = 92 kJ mol1 What is the effect of introducing a catalyst on this reversible reaction? A It increases the equilibrium yield of ammonia. B It increases the equilibrium constant for the forward reaction. C It increases the rate constant for both the forward and the reverse reaction. D It increases the rate constant for the forward reaction but not the reverse reaction. 10 An aqueous solution was prepared containing 1.0 mol of AgNO 3 and 1.0 mol of FeSO 4 in 2.00 dm 3 of water. When equilibrium was established, there was 0.44 mol of Ag +(aq) in the mixture. Ag+(aq) + Fe2+(aq) Ag(s) + Fe3+(aq) What is the numerical value of Kc? A 1.35 B 1.62 C 2.89 D 5.79 11 Which of the following equations illustrates the lattice energy of MgO? A Mg(s) + ½ O2 (g) → MgO(s) B Mg2+(aq) + O2-(aq) → MgO(s) C Mg2+(g) + O2- (g) → MgO(s) D Mg(g) + O(g) → MgO(s)

5 @YIJC [Turn Over 12 The standard enthalpy change of formation of NO is +90 kJ mol–1. What is the enthalpy change of the reaction shown below? 2NO(g) → N2(g) + O2(g) A –180 kJ mol–1 B –90 kJ mol–1 C +90 kJ mol–1 D +180 kJ mol–1 13 The diagram below illustrates the energy changes for a set of reactions. Which of the following statements is correct? A D has a higher energy content than B. B The transformation A  D is endothermic. C The transformation C  B is exothermic. D The enthalpy change for the transformation A  C is –45 kJ mol–1. 14 Methanesulfonic acid is a monoprotic strong acid which is used to remove calcium carbonate from kettles. methanesulfonic acid Which statement about methanesulfonic acid is incorrect? A The Ka value of methanesulfonic acid is very small. B 0.1 mol dm–3 methanesulfonic acid has a pH value of 1. C The Brønsted-Lowry conjugate base of methanesulfonic acid is the CH3SO3– ion. D The gas evolved when methanesulfonic acid reacts with magnesium is H2.

6 @YIJC [Turn Over 15 At 25C, Kw= 1.00 x 1014 mol2dm6. At 50C, Kw= 5.48 x 1014 mol2dm6. Which row is correct? the ionisation of water is at 50C, water with a pH of 7.0 is A endothermic alkaline B endothermic neutral C exothermic alkaline D exothermic neutral 16 Which pair of solutions will produce an acidic buffer solution upon mixing equal volumes of each solution? A 1.50 mol dm3 of HCl and 1.00 mol dm3 of NaOH B 1.00 mol dm3 of NH3 and 2.00 mol dm3 of HCl C 0.50 mol dm3 of H2SO4 and 2.00 mol dm3 of NH3 D 1.00 mol dm3 of C6H5CO2H and 0.50 mol dm3 of KOH 17 A non-cyclic organic compound has the molecular formula C4H9O2N. Which pair of functional groups could not be present in the molecule? A one carboxylic acid group and one amine group B one alcohol group and one amide group C one ester group and one amine group D one alkene group and one carboxylic acid group 18 Which pairs of molecules are constitutional (structural) isomers? 1 CH3CH2CH(CH3)2 and (CH3)4C 2 Butanone and 2-methylpropanal 3 A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

7 @YIJC [Turn Over 19 P and Q are two straight-chain unsaturated hydrocarbons with the molecular formula C4H8. Each react separately with bromine gas. The products of the two reactions are different isomers. Which pair of names could identify the two organic products made? A 1, 1-dibromobutane and 1,2-dibromobutane B 1,2-dibromobutane and 2,3