2023 RI Prelim H2 Chem Paper 1 Question Paper

1 © Raffles Institution 2023 9729/01/S/23 [Turn Over RAFFLES INSTITUTION 2023 YEAR 6 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 22 September 2023 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Do not open this question booklet until you are told to do so. Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and index number in the spaces provided on the Answer Sheet. There are thirty 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 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 the question booklet. The use of an approved scientific calculator is expected, where appropriate. This document consists of 13 printed pages and 1 blank page.

2 © Raffles Institution 2023 9729/01/S/23 [Turn Over 1 Which simple covalent molecule is non-polar? A CH2F2 B SF4 C NF3 D BeF2 2 In octa-1,3,7-triene, three of the carbon-carbon bonds are labelled p, q and r. p q r octa-1,3,7-triene What is the correct order of decreasing bond strength? A p → r → q B p → q → r C r → q → p D r → p → q 3 Which bonding type does not correspond to its description of physical properties? bonding type physical properties A giant covalent high melting point, conducts electricity when in solution but not when solid B simple covalent low melting point, does not conduct electricity in any state C metallic variety of melting points, conducts electricity when solid and when molten D ionic high melting point, conducts electricity when molten but not when solid 4 Use of the Data Booklet is relevant to this question. The table shows the seventh, eighth, ninth and tenth ionisation energies of an element in the third period. 7th 8th 9th 10th ionisation energy / kJ mol–1 20 117 25 496 28 932 141 362 Which element has these ionisation energy values? A Na B Mg C Al D Si

3 © Raffles Institution 2023 9729/01/S/23 [Turn Over 5 Down the group, the atomic radius of the elements increases. Which statements explain this? 1 The number of protons increases. 2 The number of electronic shells increases. 3 The electrostatic forces of attraction between the nucleus and valence electrons increases. A 1 only B 2 only C 2 and 3 only D 1, 2 and 3 6 X and Y are two different samples of the same ideal gas. Given that X contains a higher mass than Y, which graph shows the correct ideal gas relationship for the two samples of gas? A B p X Y T pV Y X V T C D T p Y X pV V Y X T

4 © Raffles Institution 2023 9729/01/S/23 [Turn Over 7 Use of the Data Booklet is relevant to this question. Compound W is a Period 3 chloride. It dissolves in water to form a solution of pH 3. Which statement best describes the observation when aqueous ammonia was added to the solution? A No precipitate was formed. B A vigorous reaction occurred, producing white fumes. C A white precipitate was formed which was insoluble in excess aqueous ammonia. D A white precipitate was formed which was soluble in excess aqueous ammonia to form a colourless solution. 8 What are the trends in the stated properties down Group 17 from chlorine to iodine? thermal stability of the hydrogen halides oxidising power of the element A increases increases B increases decreases C decreases increases D decreases decreases 9 Use of the Data Booklet is relevant to this question. Which contains the greatest number of molecules? A 9.60 g of ozone, O3 B 14.2 g of chlorine gas C 2.41 × 1023 molecules of methyl ethanoate D 2.4 dm3 of carbon dioxide (measured at r.t.p.)

5 © Raffles Institution 2023 9729/01/S/23 [Turn Over 10 Acidified cerium(IV) sulfate is a strong oxidising agent which reacts with hydrogen peroxide in a 2:1 mole ratio. In a titration, a solution of hydrogen peroxide required 25.00 cm3 of cerium(IV) sulfate to reach the end-point. Which statements about the titration are correct? 1 A gas is given off during the reaction. 2 The reduced cerium has an oxidation state of +3. 3 If the titration was carried out using acidified KMnO 4 of the same concentration as the titrant, the titre volume will be greater than 25.00 cm3. A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 11 Use of the Data Booklet is relevant to this question. A student mixes 20.0 cm3 of 1.00 mol dm−3 barium hydroxide with an equal volume of 2.50 mol dm−3 ethanoic acid. The initial temperature of both solutions is 25.0 °C. The maximum temperature reached after the reaction is 37.5 °C. Assume the density of both solutions is 1 g cm−3. What is the value for the enthalpy change of neutralisation calculated using these values? A −5.23 kJ mol−1 B −26.2 kJ mol−1 C −52.3 kJ mol−1 D −105 kJ mol−1

6 © Raffles Institution 2023 9729/01/S/23 [Turn Over 12 Which class of reaction always has an endothermic enthalpy change? A hydration B atomisation C formation D solution 13 The Haber Process is an example of an important industrial reaction. N2(g) + 3H2(g) ⇌ 2NH3(g) ∆H = –92 kJ mol–1 Which statements are correct? 1 When temperature is increased, the yield of NH3 decreases. 2 When the total volume is increased, the yield of NH3 decreases. 3 When more catalyst is added, the yield of NH3 increases. A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 14 The mechanism for the reaction of NO and O2 to form NO2 is given below. step 1: NO + NO ⇌ N2O2 step 2: N2O2 + O2 → 2NO2 (slow) Which statements are correct? 1 The overall order of the reaction is 3. 2 The rate equation contains NO only. 3 If the reaction occurred via a single-step mechanism, the same rate equation would be obtained. A 1 only B 3 only C 1 and 3 only D 2 and 3 only

7 © Raffles Institution 2023 9729/01/S/23 [Turn Over 15 Values for the ionic product of water, Kw, at two different temperatures are given below. temperature/ °C Kw / mol2 dm–6 25 1.00 × 10–14 30 1.44 × 10–14 What is correct for pure water at 30 °C? A [H+] > [OH–] B [H+] = 1.44 × 10–7 mol dm–3 C pH < 7 D pH = 7 16 When 0.10 mol dm–3 ethanoic acid is titrated against 0.10 mol dm–3 sodium hydroxide, the equivalence point has a pH of 8.72. Which is the best indicator for this titration? indicator approximate pH range A methyl orange 3.2 – 4.4 B phenol red 6.8 – 8.2 C thymol blue 8.0 – 9.6 D indigo carmine 11.6 – 14.0 17 Under suitable conditions, butane reacts with bromine to produce bromoalkanes. Which statement about this reaction is correct? A HBr is formed during the termination step. B Hexane is a suitable solvent for the reaction. C The reaction does not involve heterolytic bond breaking. D Small amounts of CH3CH2C(CH3)2CH2CH3 is produced from the reaction.

8 © Raffles Institution 2023 9729/01/S/23 [Turn Over 18 When one mole of cyclohex-3-en-1-one reacts with one mole of HBr, isomers of C6H9OBr are formed. O cyclohex-3-en-1-one How many possible isomers, including stereoisomers, of C6H9OBr can be formed from the reaction? A 2 B 3 C 4 D 5 19 Octenol is known to attract mosquitoes. OH octenol When octenol is heated with acidified KMnO4, organic product Z is formed. Which statement is correct? A Octenol has a higher molecular mass than Z. B O