RI 2024 H2 Chem Y6 TP QP

1 This document consists of 38 printed pages and 1 blank page. RAFFLES INSTITUTION 2024 YEAR 6 TERM 3 TIMED PRACTICE Higher 2 CANDIDATE NAME CLASS INDEX NUMBER CHEMISTRY 9729 26 Jun 2024 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 page at the end of the booklet for Section B (page 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 pages at the end of the booklet for Section C (pages 37 – 38). The question number must be clearly shown. Write in dark blue or black pen. You may use a n 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 / 7 B2 / 14 B3 / 19

2 © Raffles Institution 2024 9729/J/24 [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 Use of the Data Booklet is relevant to this question. 0.523 mol of an iron oxide, FexOy, was reacted with excess carbon monoxide in an enclosed vessel to produce carbon dioxide and 146 g of molten iron. The resultant gas mixture was passed through aqueous sodium hydroxide. The volume of the gas was reduced by 75.4 dm3 (measured at r.t.p.). What are the values of x and y? x y A 1 1 B 2 3 C 5 6 D 5 7 2 5 moles of halide ion, X −, can react with 1 mole of XO n− to form a single halogen -containing product. Which row shows the value of n and the identity of the halogen-containing product? n halogen-containing product A 1 X2 B 2 XO− C 3 X2 D 4 XO− 3 Use of the Data Booklet is relevant to this question. What is the electronic configuration of Fe3+? A [Ar] 3d5 C [Ar] 3d44s1 B [Ar] 3d6 D [Ar] 3d34s2

3 © Raffles Institution 2024 9729/J/24 [Turn Over 4 Which statements are the result of hydrogen bonding? 1 CH3CH2CONH2 is neutral. 2 The Mr of CH3CO2H in the vapour state is 120. 3 Gaseous (CH3)3N is more basic than gaseous (CH3)2NH. 4 HO OH O O HO OH OO A 1, 2 and 3 C 2 and 3 only B 1, 3 and 4 D 2 and 4 only 5 The mechanism for a given reaction is shown below. 2E ⇌ G fast G + F → H slow H + F → E2F2 fast Which statements are correct? 1 The rate equation is rate = k[E]2[F]. 2 The overall equation is 2E + 2F → E2F2. 3 The mechanism involves two transition states. A 1, 2 and 3 C 2 and 3 only B 1 and 2 only D 1 only The Ka1 of is smaller than that of .

4 © Raffles Institution 2024 9729/J/24 [Turn Over 6 The rate of the reaction between Br 2 and HCOOH was investigated by using a spectrophotometer to measure the absorbance of the solution. The absorbance of the solution is directly proportional to the concentration of Br2(aq). Br2(aq) + HCOOH(aq) → 2HBr(aq) + CO2(g) The table shows pairs of quantities that were plotted as graphs. Which pairs could have given the following graph? y-axis x-axis 1 absorbance time 2 [Br2(aq)] time 3 pressure time 4 rate [Br2(aq)] A 1, 2 and 3 C 1 and 2 only B 1 and 3 only D 1, 2 and 4 7 In which reaction is ammonia acting as an acid? A 2NH3(l) + 2Na(s) → 2NaNH2(s) + H2(g) B NH3(g) + H2O(l) → NH4+(aq) + OH–(aq) C 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) D 4NH3(aq) + Cu2+(aq) → [Cu(NH3)4]2+(aq) y-axis x-axis0

5 © Raffles Institution 2024 9729/J/24 [Turn Over 8 The pH change when 0.100 mol dm –3 of a weak acid is added dropwise to 10.0 cm 3 of 0.100 mol dm–3 NaOH is shown below. Which statements are correct? 1 The weak acid is a monobasic acid. 2 pH of the solution at point B is above 7. 3 A buffer solution with maximum buffering capacity is formed at point A. A 1 only C 2 and 3 only B 1 and 2 only D 1, 2 and 3 9 The following are pKa values for phosphoric acid, H3PO4, at 25 °C. species pKa values H3PO4 2.15 H2PO4− 7.20 HPO42− 12.38 Which substances, in aqueous solution, would be the most suitable to prepare a buffer of pH 7.4? A K2HPO4 and NaOH C NaH2PO4 and HCl B H3PO4 and NaH2PO4 D NaH2PO4 and K2HPO4 volume of weak acid added / cm3 pH 10 5 15 20 0 A B C D

6 © Raffles Institution 2024 9729/J/24 [Turn Over 10 The values of two solubility products are given. Ksp [Ca(IO3)2] = 6.47 x 10–6 mol3 dm–9 Ksp [Pb(IO3)2] = 3.69 x 10–13 mol3 dm–9 Solid calcium iodate is shaken with water and the remaining solid is filtered off, leaving a saturated solution Z. Drops of aqueous lead(II) nitrate are added to Z until lead(II) iodate just precipitates. Which row is correct? [IO3–(aq)] in Z after filtration / mol dm–3 [Pb2+(aq)] when Pb(IO3)2 just precipitates / mol dm–3 A 0.0117 3.15 x 10–11 B 0.0117 2.70 x 10–9 C 0.0235 1.58 x 10–11 D 0.0235 6.68 x 10–10 11 Cinnamaldehyde gives cinnamon its flavour and aroma. Which statement about cinnamaldehyde is correct? A It contains three sp2 hybridised carbon atoms. B It gives a positive test with Fehling’s solution, but not Tollens’ reagent. C 1 mole of cinnamaldehyde reacts with 1 mole of Br2 dissolved in CCl4. D 1 mole of cinnamaldehyde reacts with hot acidified K 2Cr2O7 to give 2 moles of carbon dioxide gas.

7 © Raffles Institution 2024 9729/J/24 [Turn Over 12 The diagram below shows a reaction sequence. Cl Cl ethanolic NaCN N LiAlH4 in dry ether P heat What could be the identity of P? A H2N NH2 C Cl NH2 B H2N NH2 D Cl NH2 13 Which compound produces the smallest volume of gas when 1 mole of each compound is reacted with excess Na2CO3(aq) at room temperature? A OH O OH HO O C O O Cl B HO OH O O CH3 D CN OH O

8 © Raffles Institution 2024 9729/J/24 [Turn Over 14 Consider the following four compounds. O O E F G H O O O O HO O What is the relative order, in decreasing basicity, of these compounds? A E > F > H > G B G > H > F > E C E > F > G > H D H > G