2023 SAJC H2 Chem Prelim P1 (QP)

ST ANDREW’S JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATIONS HIGHER 2 CANDIDATE NAME CLASS 2 2 S CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 9729/01 15 September 2023 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name and class on the Answer Sheet in the spaces provided. There are thirty questions on 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. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The use of an approved scientific calculator is expected, where appropriate. This document consists of 15 printed pages (including this cover page) and 1 blank page.

2 1 The relative atomic mass of boron, which consists of the isotopes 10 5 B and 11 5 B is 10.8. What is the percentage of 11 5 B atoms in the isotopic mixture? A 0.2 % B 0.8% C 20 % D 80 % 2 A mixture of sodium iodide, 23Na127I, and sodium bromide, 23Na79Br, were vapourised and the ions passed through an electric field. Which statements about the results are correct? 1 There would be 4 angles of deflections observed. 2 The particle with the largest angle of deflection will be detected at the negative plate. 3 The positive plate will detect more particle types than the negative plate. A 1 only B 2 and 3 only C 1 and 2 only D 1,2 and 3 3 Which of the following statements about ice and its structure is correct? A The bond angle around O in ice is 109.5°. B Ice is more dense than water. C 2 electrons on O in ice are involved in hydrogen bonding. D Hydrogen bonds formed in ice are as strong as the O-H covalent bonds. 4 Benzylamine is commonly used in the industrial production of many pharmaceutical products and has the following structure. NH2 Which bond angle is not present in benzylamine? A 105° B 107° C 109.5° D 120° 5 In a vessel, 5.0 dm3 of nitrogen gas at 20 °C and pressure of 200 kPa was compressed by a piston to 2.5 dm3 and heated to 60 °C. What is the pressure in the heated vessel? A 90 kPa B 455 kPa C 715 kPa D 1200 kPa

3 [TURN OVER 6 Magnesium, aluminium, silicon and phosphorus are consecutive elements in Period 3 of the Periodic Table. Which of the following properties generally decreases from magnesium to phosphorus? 1 Electrical conductivity 2 Ionic radius 3 Melting point of their oxides 4 pH of their chlorides in water A 1 and 2 only B 1 and 3 only C 2 and 4 only D 3 and 4 only 7 Which of the following properties of a salt will make it the most soluble in water? size of the ions magnitude of their lattice energy A small small B small large C large small D large large

4 8 A reaction involving 3 species, F, G and H have the following rate equation. rate = k[G][H]2 Which of the following graphs will be obtained? A When [G] and [H] are kept constant, B When [G] and [H] are kept constant, C When [F] and [G] are kept constant, D When [F] and [H] are kept constant, rate / mol dm–3 s–1 [F] / mol dm–3 [F] / mol dm–3 time / s rate / mol dm–3 s–1 [H]2 / mol2 dm–6 [G] / mol dm–3 time / s

5 [TURN OVER 9 Use of the Data Booklet is relevant to this question. Hydrogen iodide decomposes according to the equation shown. 2HI H2 + I2 The density of pure hydrogen iodide at 298 K is 2.85 g cm–3. Which expression gives the concentration of hydrogen gas that are present in 1.00 dm3 of pure hydrogen iodide at 298 K? A Kc√ 2.85 127.9 B 2.85 127.9 √Kc C √2850 127.9 Kc D 2850 127.9 √Kc 10 A weak monoacidic base, J, has a pKb value of 3.5. 25.0 cm3 of 0.08 mol dm-3 HCl is titrated against 0.10 mol dm-3 of J. Which statements about the titration curve obtained are correct? 1 A suitable indicator for this titration is methyl orange. 2 The pH at maximum buffer capacity is 3.5. 3 The region of rapid pH change occurs at 20 cm3. 4 The volume at maximum buffer capacity is 10 cm3. A 1 and 3 only B 2 and 4 only C 1,2 and 3 only D 2,3 and 4 only 11 The Ksp of Mg(OH)2 is 1.5 × 10 −11 mol3 dm−9 and the Kb of aqueous CH 3CH2NH2 is 5.6 × 10−4 mol dm−3. What is the solubility of Mg(OH)2 in 1.0 mol dm−3 aqueous CH3CH2NH2? A 1.64 x 10−4 mol dm−3 B 2.68 x 10−8 mol dm−3 C 4.78 x 10−9 mol dm−3 D 6.34 x 10−10 mol dm−3

6 12 AgCl and AgBr are both partially soluble solids. AgX (s) Ag+ (aq) + X− (aq), where X is Cl or Br ------- equation 1 When aqueous NH 3 is added to separate solutions of each silver halide, only AgC l dissolves but not AgBr. Which of the following statements that explains this observation is correct? A The Ksp value of AgCl is larger than that of AgBr. B The ionic product for AgCl decreases but not the ionic product of AgBr. C The addition of NH 3 resulted in the formation of the Ag(NH 3)2+ complex for only AgCl. D The concentration of Ag +(aq) decreases causing the position of equilibrium of equation 1 to shift to the left. 13 Which of the following statements explains the increase in reducing power of Group 2 element down the group? A The increase in the nuclear charge down the group. B The increase in the number of electron shells down the group. C The melting point of Group 2 metals decreases down the group. D The electronegativity of Group 2 metals decreases down the group. 14 A student added 2 cm3 of aqueous potassium iodide, KI, into a test tube, followed by bromine, Br2, dissolved in an organic solvent of density 1.59 g cm–3. He then mixed the solution thoroughly before allowing it to settle. Which of the following will be observed? Observation of the organic solvent Final colour of the lower layer in the test tube A orange-red to purple colourless B orange-red to purple purple C remained orange-red colourless D remained orange-red orange-red

7 [TURN OVER 15 Cephalotaxine is an alkaloid which has anti-leukemic activity. N O O CH3 O O Cephalotaxine How many carbon atoms are sp2 hybridised? A 7 B 8 C 9 D 10 16 How many constitutional isomers with molecular formula C 6H12O2 are esters that form ethanoic acid upon hydrolysis? A 2 B 3 C 4 D 5

8 17 Which could be the possible product from the termination step in the chain reaction when 2-methylbutane reacts with Br2, in the presence of UV light? A B C D 18 When trichlorofluoromethane, CCl3F, is released into the atmosphere, it accumulates in the upper part of the atmosphere when it reacts to form free radicals due to the action of the ultraviolet light. One of the chain reactions which can occur is shown where, Y● represents the halogen radical. Y● + O3 YO● + O2 2YO● + O2 2Y● + 2O2 1 Both Cl● and F● are the free radicals that cause the breakdown of ozone. 2 The halogen radical acts as a catalyst in the breakdown of the ozone. 3 YOY is one possible product formed in the termination step. Which statements are correct? A 1, 2 and 3 B 1 only C 2 and 3 only D 2 only

9 [TURN OVER 19 The following molecule, T, can be synthesised from benzene via several steps. COOH NH2 Br T Which of the following synthesis routes would give the highest yield for T? A alkylation → oxidation → nitration → reduction → bromination B nitration → alkylation → oxidation → reduction → bromination C alkylation → nitration → oxidation → bromination → reduction D nitration → alkylation → oxidation → bromination → reduction 20 Equal amounts of compounds W, X, Y and Z are added separately to four test -tubes c