2022 HCI Prelim P1 Question Paper

This document consists of 13 printed pages. HWA CHONG INSTITUTION C2 Preliminary Examinations Higher 2 CANDIDATE NAME CT GROUP 21S CENTRE NUMBER INDEX NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 9729/01 19 September 2022 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Complete the information on the Answer Sheet as shown below. 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. 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.

2 © Hwa Chong Institution 2022 9729/01/C2 Preliminary Exam [Turn over 1 Which formula represents a particle wi th the composition of 1 proton, 2 neutrons and 3 electrons? (D represents deuterium, 2H; and T represents tritium, 3H) A H− B D2− C T2− D He− 2 The variation in the second ionisation energy of six consecutive elements in the Periodic Table is shown in the graph. Which element is a Group 13 element? proton number 3 Which observation cannot be explained by intermolecular hydrogen bonding? A Methanol dissolves readily in water. B The boiling point of HBr is higher than that of HCl. C The boiling point of 4-aminophenol is higher than that of 2-aminophenol. D The relative molecular mass of ethanoic acid when dissolved in hexane is 120. 4 In which pairs of compounds does the first molecule have a smaller bond angle than that in the second molecule? 1 NF3 CCl4 2 H2O XeF4 3 SF6 CS2 A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 and 3 only 2nd ionisation energy / kJ mol−1 B C D A

3 © Hwa Chong Institution 2022 9729/01/C2 Preliminary Exam [Turn over 5 The following graphs were obtained for three gases for the variation of pV with p, where p is the pressure and V is the volume of the gas. Which row is correct if gas X is HCl at 300 K? gas Y temperature / K A HCl 400 B CH4 400 C O2 300 D HF 300 6 Methyl red (C15H15N3O2) is an organic compound used as an acid-base indicator. Why does methyl red, which is red in acidic solutions, turn yellow in alkaline solutions? A It is oxidised by OH− ions. B It is reduced by OH− ions. C It forms a cation by gain of H+ ions. D It forms an anion by loss of H+ ions. pV p Ideal gas Gas X Gas Y

4 © Hwa Chong Institution 2022 9729/01/C2 Preliminary Exam [Turn over 7 Group 2 nitrates undergo thermal decomposition to give the metal oxide , nitrogen dioxide and oxygen. 0.118 g of a Group 2 nitrate was thermally decomposed and the residue was dissolved in 80.0 cm3 of 0.0350 mol dm −3 HCl(aq). The resultant solution required 21.60 cm3 of 0.0780 mol dm−3 NaOH(aq) for complete neutralisation. What was the Group 2 metal in the nitrate? A Mg B Ca C Sr D Ba 8 Astatine is below iodine in Group 17 of the Periodic Table. Which properties are likely correct for astatine and its compounds? 1 Astatine is less volatile than iodine. 2 Silver astatide has less covalent character than silver iodide. 3 When a heated glass rod is inserted into a container of hydrogen astatide, it decomposes into its elements. A 1 and 3 B 1 and 2 C 3 only D 2 only 9 A 0.483 g sample of glycine (Mr = 75) was placed in a bomb calorimeter and then ignited in the presence of excess oxygen. The temperature rose by 0.54 °C. In a separate experiment using the same calorimeter, the combustion of 0.986 g of benzoic acid (Mr = 122) gave a temperature rise of 2.14 °C. The enthalpy change of combustion of benzoic acid is −3054 kJ mol−1. What is the enthalpy change of combustion, in kJ mol−1, of glycine? A −615 B −967 C −2423 D −3812

5 © Hwa Chong Institution 2022 9729/01/C2 Preliminary Exam [Turn over 10 Group 2 hydroxides undergo thermal decomposition in a similar fashion to Group 2 carbonates. Barium hydroxide undergoes decomposition as shown in the equation below: Ba(OH)2(s) → BaO(s) + H2O(g) H > 0 Which statements about this reaction are correct? 1 The Gibbs free energy change can be positive or negative depending on the temperature. 2 The decomposition is spontaneous only at high temperature. 3 The entropy change is negative. 4 Barium hydroxide decomposes at a lower temperature than magnesium hydroxide. A 1 and 2 only B 1 and 3 only C 2 and 4 only D 1, 2 and 4 only 11 The equation for the bromination of propanone is shown below. CH3COCH3 + Br2 CH3COCH2Br + H+ + Br − The rate of disappearance of the bromine colour was measured for several different concentrations of CH3COCH3, Br2 and H+ at a certain temperature. [CH3COCH3]/ mol dm−3 [Br2]/ mol dm−3 [H+]/ mol dm−3 rate of disappearance of Br2 colour/ mol dm−3 s−1 0.30 0.05 0.05 5.70 × 10−5 0.30 0.10 0.05 5.70 × 10−5 0.30 0.05 0.10 1.14 × 10−4 0.40 0.05 0.20 3.04 × 10−4 Which statement about the above reaction is correct? A The rate equation for the reaction is rate = k[CH3COCH3][Br2]. B The rate constant for the reaction is 3.80 × 10−3 mol−1 dm3 s−1. C The rate constant of the reaction doubles when [CH3COCH3] is doubled. D The time taken for the concentration of CH3COCH3 to decrease to half its initial value is the same for all experiments. H+

6 © Hwa Chong Institution 2022 9729/01/C2 Preliminary Exam [Turn over 12 Which statement about the Haber process for the manufacture of ammonia is correct? A At higher temperatures, the yield decreases but the rate of production of ammonia is faster. B At lower temperatures, the value of Kp decreases. C At higher pressures, the yield decreases but the rate of production of ammonia is faster. D In the presence of a catalyst, the yield decreases but the rate of production of ammonia is faster. 13 0.50 moles of CH 3CO2H and 0.50 moles of CH 3CH2OH were mixed and an esterification reaction took place. The equilibrium constant for this reaction is 4.0. What is the amount of CH3CO2H (in moles) in the mixture at equilibrium? A 0.17 B 0.25 C 0.33 D 0.67 14 Use of the Data Booklet is relevant to this question. Water dissociates as shown. H2O ⇌ H+ + OH− At 25 C, the equilibrium value of [H+] is 10−7 mol dm−3; [H2O] = 55.6 mol dm−3. What is the order of increasing numerical value of pH, pKa and pKw for this equilibrium at this temperature? smallest largest A pH pKa pKw B pH pKw pKa C pKa pKw pH D pKw pKa pH

7 © Hwa Chong Institution 2022 9729/01/C2 Preliminary Exam [Turn over 15 Which combination of substances would result in a buffer solution? A 25.0 cm3 of 0.100 mol dm−3 HCl(aq) and 20.0 cm3 of 0.100 mol dm−3 NaCl(aq) B 25.0 cm3 of 0.100 mol dm−3 HCl(aq) and 25.0 cm3 of 0.200 mol dm−3 NH3(aq) C 25.0 cm3 of 0.100 mol dm−3 H2CO3(aq) and 50.0 cm3 of 0.100 mol dm−3 NaOH(aq) D 20.0 cm 3 of 0.100 mol dm −3 CH3CO2H(aq) and 25.0 cm 3 of 0.100 mol dm −3 NaOH(aq) 16 The following graph represents how the solubility of a sparingly soluble salt lead( II) iodide, PbI2, changes upon addition of solid potassium iodide at a fixed temperature. Which statement about the above graph is not correct? A The change in solubility along PQ is due to commo