RI 2017 Y5 Promo QP

© Raffles Institution 2017 9729/S/17 [Turn Over RAFFLES INSTITUTION 2017 YEAR 5 PROMOTION EXAMINATION Higher 2 CHEMISTRY 27 September 2017 2 h 30 min Additional Materials: Multiple Choice Answer Sheet Data Booklet Writing Paper Graph Paper READ THESE INSTRUCTIONS FIRST Write your name, class and index number in the spaces provided on the OMR Answer Sheet, the cover sheet on page 11 and the writing paper used for Section C. Do not use staples, paper clips, highlighters, glue or correction fluid. This paper consists of three sections, A, B and C. Answer all questions. Section A (16 marks) You must answer this section first. The OMR Answer Sheet will be collected 35 minutes after the commencement of the examination. There are sixteen questions in th is section. 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 OMR 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 the question booklet. Section B (34 marks) Answers to this section are to be written on the question paper in the spaces provided. Section C (40 marks) Answers to this section are to be written on the writing paper provided. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs or rough working. You are reminded of the need for good English and clear presentation in your answers. At the end of the examination, fasten your answers to Section C securely together. Answers to Sections A, B and C are to be handed in separately. This document consists of 22 printed pages. This document is copyrighted, please do not reproduce it without permission

© Raffles Institution 2017 9729/S/17 [Turn Over 2 Section A For each question, there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 Which statement about relative molecular mass is correct? A It is the sum of the relative isotopic masses of the most abundant iso tope of each atom within the molecule. B It is the ratio of the weighted average mass of a molecule to 1 12 the mass of 1 mole of 12C atoms. C It is the ratio of the weighted average mass of 6.02 × 1023 molecules to the mass of a 12C atom. D It is the sum of the relative atomic masses of all the atoms within the molecule. 2 A cation G2+ is isoelectronic to PH3. What is the ground state electronic configuration of G? A 1s2 2s2 2p6 3s2 3p4 B 1s2 2s2 2p6 3s2 3p6 C 1s2 2s2 2p6 3s2 3p6 3d2 D 1s2 2s2 2p6 3s2 3p6 4s2 3 Which particles have one unpaired d electron? 1 copper ion in Cu2O 2 zinc ion in Zn(NO3)2 3 titanium ion in Ti2(SO4)3 A 3 only B 1 and 2 C 1 and 3 D 2 and 3 This document is copyrighted, please do not reproduce it without permission

© Raffles Institution 2017 9729/S/17 [Turn Over 3 4 The table below shows some typical bond lengths. bond bond length / nm N=N 0.120 N≡N 0.110 N–O 0.147 N=O 0.115 The bond lengths in n itrous oxide, N 2O, are not what might be expected. The nitrogen–nitrogen bond length in N 2O is 0.112 nm and the nitrogen –oxygen bond length is 0.119 nm. Which statement explains why the N≡N bond length in N2O is longer than 0.110 nm? A The π bonds between N (1) and N(2) are weakened by the dative covalent bond between N(2) and O. B The electrons in the O atom are attracted towards the π bonds between N(1) and N(2). C The electrons in the unhybridised 2p orbitals on N(1) and N(2) repel one another. D The π electrons between N(1) and N(2) are delocalised over N(2) and O. 5 A frictionless gas syringe contains gas J and 0.058 g of a volatile liquid L (Mr = 46.0). Upon heating to 100 oC, liquid L is completely vaporised. The gases occupy a total volume of 80 cm3. Atmospheric pressure is 101 kPa. Assuming that the gases behave ideally and do not react with each other , what is the mole fraction of J in the gaseous mixture? A 0.999 B 0.870 C 0.516 D 0.484 This document is copyrighted, please do not reproduce it without permission

© Raffles Institution 2017 9729/S/17 [Turn Over 4 6 The lattice energies (LE) of two compounds are given below. compound experimental LE / kJ mol–1 NaF –915 MgO –3933 Which statement best explains the difference between the two values? A The radius of the oxide ion is greater than that of the fluoride ion. B The charge on the magnesium ion is greater than that on the sodium ion. C The radius of the magnesium atom is smaller than that of the sodium atom. D The difference in electronegativity between sodium and fluorine is greater than that between magnesium and oxygen. 7 Propanone reacts with iodine in the presence of sulfuric acid as the catalyst. H2SO4 CH3COCH3(aq) + I2(aq) CH3COCH2I(aq) + H+(aq) + I–(aq) propanone Which is the most suitable method to determine the order of this reaction with respect to sulfuric acid? A Measure the rate of change of [H +] several times by sampling and titrating against a standard solution of NaOH, but with a different initial [CH3COCH3] each time. B Measure the rate of change of [I2] several times by sampling and titrating against a standard solution of Na2S2O3, but with a different initial [I2] each time. C Measure the rate of change of electrical conductivity several times, but at a different temperature each time. D Measure the rate of decolourisation of I2 several times, but with a different initial [H2SO4] each time. This document is copyrighted, please do not reproduce it without permission

© Raffles Institution 2017 9729/S/17 [Turn Over 5 8 Bromide ions can be oxidised by bromate(V) ions under acidic conditions. 5Br – (aq) + BrO3 –(aq) + 6H+(aq) 3Br2(aq) + 3H2O(l) The progress of the reaction may be followed by adding a small amount of phenol together with three drops of methyl red indicator. The bromine produced during the above reaction reacts quickly with phenol as shown below. Once all the phenol is consumed, any additional bromine that is produced will bleach the indicator completely. The time taken, t, for the complete disappearance of the red colour of the indicator is measured. experiment number volume of KBrO3 / cm3 volume of KBr / cm3 volume of H2SO4 / cm3 volume of phenol / cm3 volume of water / cm3 time, t / s 1 5 25 30 2 40 104 2 5 25 60 2 10 26 3 10 25 60 2 5 13 4 5 50 15 2 30 208 5 10 100 30 4 60 x Which of the following statements is correct? A The value of x is 416. B The overall order of the reaction is 4. C The units of the rate constant are mol–2 dm6 s–1. D Increasing the concentration of phenol added will result in a smaller value of t. This document is copyrighted, please do not reproduce it without permission

© Raffles Institution 2017 9729/S/17 [Turn Over 6 9 The Harcourt and Esson reaction is shown below. H2O2 + 2I– + 2H+ 2H2O + I2 The rate equation of the reaction is rate = k[H2O2][I–]. The following two reaction mixtures are prepared to study the change in concentration of H2O2 during the reaction. reaction mixture initial [H2O2] / mol dm–3 initial [I–] / mol dm–3 initial [H+] / mol dm–3 I 0.0200 0.400 0.400 II 0.0200 0.200 0.200 The half-life of H2O2 in r