RI 2023 Y6 H2 Chemistry Common Test QP

1 This document consists of 35 printed pages and 1 blank page. RAFFLES INSTITUTION 2023 YEAR 6 TERM 3 COMMON TEST Higher 2 CANDIDATE NAME CLASS INDEX NUMBER CHEMISTRY 9729 26 June 2023 2 hours 45 minutes Additional Materials: Multiple Choice Answer (OMR) Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, 6- digit exam index number and civics tutorial group in the spaces provided on the OMR sheet and the cover sheets on pages 1 and 21 . Shade your 6-digit exam index number on the OMR 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. The OMR sheet will be collected after the first 30 minutes. 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 sheet. 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 paper. Section B (40 marks) consists of 3 structured questions. Answer all questions in the spaces provided in the question paper. If additional space is required, you should use the pages at the end of the booklet for Section B (pages 19 – 20). The question number must be clearly shown. Section C (40 marks) consists of 4 free-response questions. Answer both C1 and C2, and only one of C3 EITHER or C3 OR. Answers to this section are to be written in the spaces provided in the question paper. If additional space is required, you should use the page at the end of the booklet for Section C (pages 36). The question number must be clearly shown. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. The number of marks is given in brackets [ ] at the end of each question or part question. Question Marks B1 / 15 B2 / 12 B3 / 13

2 © Raffles Institution 2023 9729/J/23 [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 Which species is deflected to the greatest extent in an electric field? A e-1 0 B H+ 1 1 C H1 1 – D He2 4 2 Use of the Data Booklet is relevant to this question. The table shows the fifth, sixth, seventh, eighth and ninth ionisation energies of an element in the third period. 5th 6th 7th 8th 9th ionisation energy / kJ mol–1 6500 9400 11000 33600 38600 Which element has these ionisation energy values? A P B S C Cl D Ar 3 The table provides the structures of four compounds. W X Y Z C C CH3 H H3C H O C CH3 CH3 O C Cl Cl C C H CH3 H3C H What is the correct order of increasing polarity? A W → Z → X → Y B W → Z → Y → X C Z → W → X → Y D Z → W → Y → X

3 © Raffles Institution 2023 9729/J/23 [Turn Over 4 In acidic solutions, BrO3– ions will slowly oxidise Br– ions to Br2. BrO3– + 5Br– + 6H+ → 3Br2 + 3H2O The following results were obtained from investigations of this reaction. experiment [BrO3–] [Br–] [H+] relative rate 1 0.10 0.10 0.30 2 2 0.10 0.20 0.15 1 3 0.10 0.20 0.30 4 4 0.20 0.20 0.30 8 What is the rate equation for this reaction? A rate = k[BrO3–] [Br–] [H+]2 B rate = k[BrO3–] [Br–]2 [H+] C rate = k[BrO3–] [Br–]2 [H+]2 D rate = k[BrO3–]2 [Br–] [H+]2 5 Hydrogen reacts with gaseous bromine to form hydrogen bromide. H2(g) + Br2(g) → 2HBr(g) The following mechanism involving free radicals has been proposed. step 1 Br2 → 2Br• step 2 Br• + H2 → HBr + H• step 3 H• + Br2 → HBr + Br• step 4 HBr + H• → H2 + Br• step 5 2Br• → Br2 The rate equation is rate = k1[H2][Br2]1.5 [Br2] + k2[HBr] Which statements about this reaction are correct? 1 The formation of HBr slows down the rate of the reaction. 2 Only steps 3 and 4 are propagation steps. 3 Doubling the concentration of Br2 doubles the rate of reaction. A 1, 2 and 3 C 2 and 3 only B 1 and 2 only D 1 only

4 © Raffles Institution 2023 9729/J/23 [Turn Over 6 A 2 dm 3 buffer consisting of 2.0 mol dm –3 ethanoic acid and 1.0 mol dm –3 sodium ethanoate has a pH of 4.46. What is the maximum mass of solid sodium hydroxide (in grams) that can be added if the pH is to be maintained below 4.60? [Mr of NaOH = 40.0] A 9.0 B 18.0 C 48.1 D 96.2 7 Which statement is correct? A Ka of water × Kb of water = Kw B When an excess of a weak base is added to a strong acid, a buffer is formed. C When an acidic buffer is diluted with a large volume of water, the pH does not change. D When aqueous H 2SO4 is titrated against aqueous NaOH, there are two regions of rapid pH change. 8 When dilute HC l is added to a solution of AgNO 3, a precipitate of AgC l is formed. When concentrated HCl is subsequently added, the white precipitate dissolves. Which of the following statements best explains the observation? A Ag+ ions form a soluble complex with Cl−. B Ag+ ions form a soluble complex with H+. C The precipitate dissolves due to the presence of the common ion Cl−. D AgCl is a Brønsted-Lowry base and reacts with H+ in an acid-base reaction.

5 © Raffles Institution 2023 9729/J/23 [Turn Over 9 Element R is in the third period (sodium to phosphorus) of the Periodic Table. The following four statements describe the properties of element R or its compounds. Three statements are correct descriptions. One of the statements is not correct because it does not fit with the other three. Which statement is not correct? A Element R has the lowest first ionisation energy in the third period. B The chloride of R reacts with water to give an acidic solution. C The oxide of R is a solid at room temperature. D The chloride of R reacts with excess water to form the oxide of R. 10 An octapeptide Q was obtained from the spike protein of SARS -CoV-2 virus. Partial hydrolysis yields the following dipeptide and tripeptide fragments. Gly-Asn-Tyr Tyr-Leu-Tyr Tyr-Asn-Tyr Tyr-Arg Which of the following is a possible sequence of Q? A Tyr-Asn-Tyr-Arg-Tyr-Leu-Gly-Asn B Tyr-Leu-Tyr-Asn-Tyr-Arg-Gly-Asn C Gly-Asn-Tyr-Arg-Tyr-Leu-Asn-Tyr D Gly-Asn-Tyr-Asn-Tyr-Leu-Tyr-Arg 11 Compound A reacted with excess hot concentrated H2SO4 to give compound B. OH HO compound A How many chiral centres does compound B have? A 2 B 3 C 4 D 5

6 © Raffles Institution 2023 9729/J/23 [Turn Over 12 Which reagents and conditions will convert the compound below to a product containing three identical substituents on benzene? H O OHO OH 1 K2Cr2O7(aq), H2SO4(aq), heat 2 LiAlH4 in dry ether 3 NaBH4 A 1, 2 and 3 C 1 only B 1 and 2 only D 2 only 13 Which reactions can be represented by the above diagram? 1 (CH3)3CCl + KOH → (CH3)3COH + KCl 2 CH3CH2Cl + KOH → CH3CH2OH + KCl 3 CH3CHO + HCN → CH3CH(OH)CN A 1 and 2 B 1 and 3 C 2 and 3 D 1 only reaction pathway energy

7 © Raffles Institution 2023 9729/J/23 [Turn Over 14 Which reagents give rise to a colour change with one of the compounds shown below, but not with the other? OH OH 1 KMnO4(aq), H2SO4(aq), heat 2 K2Cr2O7(aq), H2SO4(aq), heat 3 neutral FeCl3(aq) 4 Br2(aq)