RI 2022 Y5 Promotional Examination QP

1 © Raffles Institution 2022 9729/S/22 [Turn Over Name: ( ) Class: 23S0____ RAFFLES INSTITUTION 2022 Year 5 Promotion Examination HIGHER 2 CHEMISTRY 9729 28 September 2022 2 hours 30 minutes Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, 6 -digit index number and civics tutorial group in the spaces provided on the OMR sheet and the cover sheets on pages 1 and 23. Shade in your 6-digit exam index number on the OMR Answer Sheet. This paper consists of three sections A, B and C. Section A (15 marks) consists of 15 multiple-choice questions. Answer this section first. Your OMR Answer Sheet will be collected after the first 30 minutes. Record your answers to this section in soft pencil on the OMR Answer Sheet. Section B (35 marks) consists of 2 structured questions. Answer all questions. Answers to this section are to be written in the spaces provided in the question paper. Section C (40 marks) consists of 3 free-response questions. Write your answers in the spaces provided in the question paper. If additional space is required, you should use page 35 at the end of the booklet for Section C. The question number must be clearly shown. The number of marks is given in brackets [ ] at the end of each question or part question. Write in dark blue or black pen. You may be subject to penalty for writing answers in pencil. Answers to Sections B and C are to be handed in separately. Question Marks B1 / 19 B2 / 16 This document consists of 34 printed pages and 1 blank page. This document is copyrighted, please do not reproduce it without permission

2 © Raffles Institution 2022 9729/S/22 [Turn Over Section A (15 marks) For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 An equimolar mixture of CS2 and H2S is completely burned in excess oxygen. What will be the SO2 : CO2 mole ratio in the mixture obtained after complete combustion? A 1 : 1 B 2 : 1 C 3 : 1 D 4: 1 2 Use of the Data Booklet is relevant to this question. An ion has • a nucleon number of 267, • 60 more neutrons than electrons, • an atomic number of 104, 105, 106 or 107. What could this ion be? A Rf2+ B Db3+ C Sg4+ D Bh5+ 3 The ionisation energies (I.E.), in kJ mol–1, of five elements are given in the table. 3rd I.E. 4th I.E. 5th I.E. O 5320 7450 10990 F 6040 8410 11023 Ne 6150 9290 12177 Na 6940 9540 13354 Mg 7740 10500 13636 Which statement is correct? A The 3rd I.E. of Na is higher than that of Ne because Na2+ has one more shell than Ne2+. B The 4th I.E. of the above elements involves the removal of an electron from the same sub-shell. C The 5th I.E. of F is higher than that of O because F 4+ has more outer shell electrons than O4+. D The successive I.E. of these elements increase because the nuclear charge increases. This document is copyrighted, please do not reproduce it without permission

3 © Raffles Institution 2022 9729/S/22 [Turn Over 4 The table identifies the shape and polarity of four molecules. Which row is correct? molecule molecular shape polarity A nitrogen trifluoride trigonal planar polar B difluoromethane tetrahedral non-polar C sulfur dioxide linear polar D phosphorus pentachloride trigonal bipyramidal non-polar 5 Which statements are correct? 1 NaHF2 forms hydrogen bonds with water molecules. 2 H2O2 forms more extensive hydrogen bonds than N2H2. 3 SF4 molecules form permanent dipole –permanent dipole interactions with polar molecules. 4 The interactions between CH3(CH2)17OH molecules are predominantly instantaneous dipole–induced dipole interactions. A 1, 2 and 3 are correct. B 2, 3 and 4 are correct. C 1 and 2 are correct. D 3 and 4 are correct. This document is copyrighted, please do not reproduce it without permission

4 © Raffles Institution 2022 9729/S/22 [Turn Over 6 A fixed mass of gas is placed in a cylinder with a moveable piston and subjected to different temperatures above the boiling point at constant pressure. Under the se experimental conditions, the gas exhibits deviation from ideal gas behaviour. Which graph correctly describes the behaviour of the gas? A B C D 7 In an experiment to measure the enthalpy change of neutralisation for the reaction between H2SO4 and NaOH, 20 cm 3 of a solution containing 0.04 mol of H 2SO4 is placed in a plastic cup of negligible heat capacity. A 20 cm3 sample containing 0.04 mol of NaOH, at the same initial temperature, is added and the temperature rises by 14 K. If the specific heat capacity of the final solution is 4.2 J K–1 cm–3, what is the enthalpy change of neutralisation for the reaction between H2SO4 and NaOH? A −2.35 kJ mol−1 B −29.4 kJ mol−1 C −58.8 kJ mol−1 D −118 kJ mol−1 T / K pV T / K pV T / K pV T / K pV This document is copyrighted, please do not reproduce it without permission

5 © Raffles Institution 2022 9729/S/22 [Turn Over 8 Which statements help to explain why magnesium and chlorine react to form MgCl2 rather than MgCl? 1 The Mg2+(g) ion is more stable than the Mg+(g) ion. 2 The lattice energy of MgCl2 is more negative than the lattice energy of MgCl. 3 The standard enthalpy change of formation of MgC l2 is more negative than that of MgCl. A 3 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 9 Some thermodynamic data for the reaction between SO2(g) and O2(g) are given. 2SO2(g) + O2(g) ⇌ 2SO3(g) ∆Hr = −197 kJ mol−1 ∆Sr = −189 J K−1 mol−1 T0 is the temperature, in Kelvin, at which the forward reaction becomes spontaneous. Assuming ∆Hr and ∆Sr do not change with temperature, which row is correct? T0 / K value of ∆Gr with increasing temperature A 1040 increases B 1.04 increases C 1040 decreases D 1.04 decreases This document is copyrighted, please do not reproduce it without permission

6 © Raffles Institution 2022 9729/S/22 [Turn Over 10 The kinetics of the acid-catalysed reaction between propanone and iodine CH3COCH3(aq) + I2(aq) ⎯→ CH2ICOCH3(aq) + HI(aq) can be investigated experimentally by varying the concentrations of the three substances involved and determining the time for the colour of the iodine to disappear. In this method, the rate of reaction is measured in terms of the rate at which the iodine concentration changes. The following results were obtained in a series of experiments. experiment volume of propanone / cm3 volume of iodine / cm3 volume of sulfuric acid / cm3 volume of water / cm3 time taken for iodine colour to disappear / s 1 8 4 8 0 1 2 8 2 8 2 0.5 3 4 4 8 4 2 4 8 8 2 2 8 Which conclusions can be drawn from the results? 1 The rate constant has units of mol−1 dm3 s−1. 2 The rate equation is rate = k[propanone][iodine]. 3 The rate of reaction for experiment 2 is the fastest. A 1 only B 3 only C 1 and 3 only D 1, 2 and 3 H+ This document is copyrighted, please do not reproduce it without permission

7 © Raffles Institution 2022 9729/S/22 [Turn Over 11 The reaction of manganate( VII) ions with ethanedioate ions in acid solution is an auto-catalytic reaction. 2MnO4−(aq) + 16H+(aq) + 5C2O42−(aq) ⎯→ 2Mn2+(aq) + 8H2O(l) + 10CO2(g) Which graph correctly represents the kinetics of this reaction? A B C D 12 The diagram shows the Maxwell –Boltzmann energy distribution curves for molecules of a sample of a gas at two different tempe