2023 ACJC H2 Chem Prelim Paper 1 QP

1 © ACJC 2023 9729/01/Prelim/2023 [Turn over Anglo-Chinese Junior College JC2 Preliminary Examination Higher 2 CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 9729/01 13 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 index number on the Answer Sheet in the spaces provided unless this has been done for you. There are thirty questions in this section. 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 this booklet. The use of an approved scientific calculator is expected, where appropriate. This document consists of 16 printed pages.

2 © ACJC 2023 9729/01/Prelim/2023 [Turn over 1 Which types of chemical bonds listed below are present in solid ammonium nitrate? 1 ionic bonds 2 dative bonds 3 hydrogen bonds A 1 only B 1 and 2 only C 1 and 3 only D 1, 2 and 3 2 1.00 mol of gaseous molecules A take up a volume of 50 dm 3 at a pressure of 2 bar and a temperature of 50 oC. Which statements explain the above observation? 1 Gaseous molecules of A are in constant rapid random motion. 2 Gaseous molecules of A have significant molecular volume. 3 Gaseous molecules of A experience strong intermolecular forces of attraction. A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 3 Two properties relating to silicon and sulfur which are non–metallic elements and their atoms are as follows. • property 1 – the oxide forms a strong acid in water • property 2 – no paired 3p electrons Which properties do silicon and sulfur have? silicon sulfur A 1 and 2 1 only B 1 and 2 1 and 2 C 2 only 1 only D 2 only 1 and 2

3 © ACJC 2023 9729/01/Prelim/2023 [Turn over 4 The Group 2 metals have higher melting points than the Group 1 metals. Which factors could contribute towards the higher melting points? 1 There are smaller interatomic distances in the metallic lattices of the Group 2 metals. 2 Two valence electrons from each Group 2 metal atom are available for bonding in the metallic lattice. 3 Group 2 metals have the higher first ionisation energy. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only 5 Which statement about the trend in the property of the halogens down the group is correct? A The electronegativity increases. B The reactivity as oxidising agents increases. C The enthalpy change of reaction with hydrogen becomes more endothermic. D The volatility increases. 6 Group 1 and Group 2 ionic hydrides react with water. H‒ + H2O → OH‒ + H2 In an experiment, 1 .01 g of a sample of an ionic hydride is dissolved in excess H2O. The resulting solution required 24.0 cm3 of a 2.0 mol dm–3 HCl solution for complete neutralisation. What is the formula of the hydride? A LiH B NaH C MgH2 D CaH2 7 Two identical iron(II) sulfate solutions were separately titrated with acidified K 2Cr2O7 and acidified KMnO4 solutions of equal concentrations. Which statement describes the required volumes of K 2Cr2O7 and KMnO4 solutions needed to completely oxidise the iron(II)? A The volume of KMnO4 solution is 0.83 times that of the volume of K2Cr2O7. B The volume of KMnO4 solution is 1.20 times that of the volume of K2Cr2O7. C The volume of KMnO4 solution is 1.82 times that of the volume of K2Cr2O7. D The volume of KMnO4 solution is 2.22 times that of the volume of K2Cr2O7.

4 © ACJC 2023 9729/01/Prelim/2023 [Turn over 8 Which reaction represents a standard enthalpy change at 298 K? A 1 2F2(g) ⟶ F(g) B C(g) + O2(g) ⟶ CO2(g) C C(s) + 4F(g) ⟶ CF4(g) D C3H8(g) + 5O2(g) ⟶ 3CO2(g) + 4H2O(g) 9 Ethane undergoes combustion as shown. C2H6(g) + 7 2O2(g) 2CO2(g) + 3H2O(l) ∆Hco = –1561 kJ mol–1 Some relevant data are given below. ∆Hco of C(s) = –394 kJ mol–1 ∆Hfo of C2H6(g) = –85 kJ mol–1 ∆Hfo of H2O(g) = –243 kJ mol–1 What is the standard enthalpy change of vaporisation of H2O(l)? A +43 kJ mol–1 B –43 kJ mol–1 C +129 kJ mol–1 D –129 kJ mol–1

5 © ACJC 2023 9729/01/Prelim/2023 [Turn over 10 The product [X][Y] of the concentrations of X and Y is plotted against time, t, for the following second-order reaction. X + Y ⟶ Z Which graph would be obtained? A B C D 0 t [X][Y] 0 t [X][Y] 0 t [X][Y] 0 t [X][Y]

6 © ACJC 2023 9729/01/Prelim/2023 [Turn over 11 Two first order reactions were started at the same time. Reaction I had an initial concentration of 1 mol dm −3 and a half -life of 20 minutes. Reaction II had an initial concentration of 4 mol dm−3 and a half-life of 10 minutes. At what time would the concentrations in the two reactions become equal? A 15 min B 35 min C 40 min D 50 min 12 The reaction between sulfur dioxide and oxygen is reversible. 2SO2(g) + O2(g) ⇌ 2SO3(g) The rate constants of the forward and backward reactions are given as k1 and k−1 respectively. What happens to the values of k1, k−1, Kc and the equilibrium position if an inert gas is introduced into the reaction vessel at constant volume? k1 k−1 Kc equilibrium position A unchanged unchanged unchanged unchanged B increases decreases increases shifts to right C decreases increases decreases shifts to left D unchanged unchanged unchanged shifts to right 13 Malic acid is a dibasic acid which is used in skincare products. The pKa values of malic acid are 3.40 and 5.20. What volume of 0.200 mol dm –3 KOH needs to be added to 20.00 cm 3 of 0.240 mol dm –3 of malic acid to form a buffer solution of pH 5.22? A 35.70 cm3 B 35.90 cm3 C 36.10 cm3 D 36.30 cm3

7 © ACJC 2023 9729/01/Prelim/2023 [Turn over 14 The indicator bromophenol blue, HIn, changes colour from yellow to blue over a pH range of 3.0 to 4.6. Which statement is correct? A When bromophenol blue is added to pure water at 25 oC, [HIn] > [In–]. B Bromophenol blue would be a suitable indicator for the titration of a strong base and a weak acid. C The In– ions are yellow. D The pKa of bromophenol blue is around 3.8. 15 The numerical value s of the solubility product s of zinc carbonate and silver carbonate are 1.46 x 10−10 and 8.46 x 10−12 respectively. Which statement can be deduced from the information given above? A The units of solubility product for both salts are the same. B In an aqueous solution containing 0.01 mol dm–3 zinc ions and 0.01 mol dm–3 silver ions, silver carbonate will be precipitated first. C In saturated solutions of each salt, the concentrations of carbonate ions are the same. D Zinc carbonate is a less soluble salt than silver carbonate in water. 16 A compound derived from plant essential oil has the following structure. When the compound is reacted with HBr in CCl4, how many new chiral centres are formed in the major product in this reaction? A 1 B 2 C 3 D 4

8 © ACJC 2023 9729/01/Prelim/2023 [Turn over 17 Unsaturated carbonyl compounds can undergo a useful reaction known as the Diels -Alder reaction with a diene. An example is shown below. A student reacted the following diene and carbonyl compound together in a Diels-Alder reaction. Which compound would not be formed as a product? A C B D

9 © ACJC 2023 9729/01/Prelim/2023 [Turn over 18 Nitrobenzene is a yellow liquid wit