2022 MI H2 Chem Prelim Paper 1 - Question

Class Adm No Candidate Name: This question paper consists of 14 printed pages and 2 blank pages. 2022 Preliminary Examination Pre-University 3 H2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 21st Sep 2022 1 hour Additional materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Do not turn over this question paper until you are told to do so Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and admission number in the spaces provided at the top of this page and on the Multiple Choice Answer Sheet 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 Multiple Choice Answer Sheet provided. Read the instructions on the Multiple Choice 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 question paper. The use of an approved scientific calculator is expected, where appropriate. FOR EXAMINER’S USE TOTAL (30 marks)

2 For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 Which of the following conversions have a percentage yield of 73%? 1 74 g of butan-1-ol (Mr = 74.0) → 52.56 g of butanal (Mr = 72.0) 2 72 g of butanone (Mr = 72.0) → 54.02 g of butan-2-ol (Mr = 74.0) 3 56 g of but-2-ene (Mr = 56.0) → 87.60 g of ethanoic acid (Mr = 60.0) A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 2 Ferric oxalate, Fe2(C2O4)3, is an ionic salt. A sample of 10.0 cm3 of 0.100 mol dm-3 ferric oxalate is titrated against 0.100 mol dm-3 acidified KMnO4. What is the volume of KMnO4 required to reach end point, and the total volume of CO2 gas evolved at r.t.p.? volume of KMnO4 volume of gas A 4.0 cm3 72 cm3 B 4.0 cm3 144 cm3 C 12.0 cm3 72 cm3 D 12.0 cm3 144 cm3 3 Use of the Data Booklet is relevant to this question. The silver chloride electrode is a type of reference electrode commonly used in electrochemical measurements. It can be represented as below. AgCl(s) + e– ⇌ Ag(s) + Cl–(aq) The reduction potential of the Co3+/Co2+ half-cell is +1.69 V when it is measured using the AgCl /Ag reference electrode at standard conditions. What is the reduction potential of the AgCl /Ag electrode when it is measured against the standard hydrogen electrode as reference? A -1.89 V B +0.20 V C +1.49 V D +1.89 V

3 [Turn over 4 Use of the Data Booklet is relevant to this question. Which of the following statements are true? 1 I2 can reduce S2O32− to S4O62−. 2 K is a stronger reducing agent than Ca. 3 When Br2(g) is bubbled into NaI(aq), an orange solution is produced. A 1 only B 2 only C 1 and 2 only D 2 and 3 only 5 The first six ionisation energies of an element, E, in kJ mol‒1 are shown. 578 1817 2745 11577 14842 18379 E forms an oxide when it is heated with oxygen gas. What is the electronic configuration of E in its oxide form? A 1s2 B 1s2 2s2 2p1 C 1s2 2s2 2p6 D 1s2 2s2 2p6 3s2 3p1 6 In which of the following pairs of compounds would the second compound have a higher boiling point than the first compound? 1 CH3CHO, CH3CH2OH 2 AlF3, AlCl3 3 CH3CH2CH2CH2CH3, C(CH3)4 A 1 only B 1 and 2 only C 1 and 3 only D 2 and 3 only

4 7 Information about the properties of some compounds are given below. compound boiling point / °C HF 19.5 NH3 −33.3 H2O 100 Which statement about the hydrogen bonding in these compounds is correct? A HF has a higher boiling point than NH 3 because each HF molecule can form more hydrogen bonds on average compared to each NH3 molecule. B H2O has a higher boiling point than HF because the H–O bond dipole is greater than the H–F bond dipole. C H2O has a higher boiling point than HF because hydrogen bonding between two molecules of H2O causes it to dimerise. D NH3 has the lowest boi ling point because it forms few hydrogen bonds on average and has the smallest bond dipole. 8 Covalent bonds involve the overlapping of orbitals. CC C CH3 H H CC H H H1 2 3 4 5 6 Which statement does not describe the molecule above? A The  bond between C2–H is formed by 2sp2–1s overlap. B The  bond between C3–C4 is formed by 2sp2–2sp2 overlap. C The  bond between C5–C6 is formed by 2sp2–2sp3 overlap. D The  bond between C4–C5 is formed by 2p–2p overlap.

5 [Turn over 9 When glucose is stirred into water and dissolved, strong hydrogen bonds are formed initially between the glucose and water molecules. As more water is added, these same hydrogen bonds are subsequently broken. Assuming that the rate of energy change remains relatively constant throughout, which of the following graphs best represents the observed temperature changes? A B C D 10 The Hc values of some hydrocarbons are given below. hydrocarbon Hc / kJ mol–1 Mr CH4 –889 16.0 C2H6 –1560 30.0 What is the ratio of heat generated by CH4 to C2H6 when the same mass of each hydrocarbon is burnt? A 0.57 B 0.94 C 1.07 D 1.14 temperature volume of water added temperature volume of water added temperature volume of water added temperature volume of water added

6 11 20 m3 of neon gas at a pressure of 30 kPa and 30 m3 of argon gas at a pressure of 50 kPa were introduced into an evacuated 15 m3 flask at a constant temperature of 300 K. The final pressure in the flask was F kPa. What is the value of F? F / kPa A 42 B 80 C 140 D 178 12 Two acid-base reactions are shown below: Reaction 1: N2H4 + HClO → N2H5+ + ClO– Reaction 2: N2H5+ + NH3 → NH4+ + N2H4 Which of the following statements is incorrect? 1 ClO– is the conjugate base of HClO. 2 N2H5+ is the Bronsted acid in Reaction 2. 3 N2H4 is the Lewis acid in Reaction 1. A 1 only B 3 only C 1 and 2 only D 2 and 3 only 13 The radioactive decay of an element, H, is a first order reaction and produces element I as the product: H → I 1.00 mol of H was set aside and allowed to decay. Given that it takes 8 days for 0.75 mol of I to be produced, what fraction of H remains after 40 days? A (1 2) 1 B (1 2) 5 C (1 2) 10 D (1 2) 25

7 [Turn over 14 N2O decomposes in the presence of gold catalyst as follows: 2N2O(g) → 2N2(g) + O2(g) The following data is obtained from an experiment carried out at 1200 K. time / s 0 1040 2370 4250 7460 partial pressure of N2O / kPa 25.0 20.0 15.0 10.0 5.0 Which of the following statements is incorrect? A The reaction is first order with respect to N2O. B The total pressure upon reaction completion can be determined from the above data. C The values of the partial pressures of N2O are affected by temperature. D The value of rate constant of the reaction remains the same even in the absence of gold. 15 CH3COOH + C2H5OH ⇌ CH3COOC2H5 + H2O Which of the following conditions will be met when t he above reaction has reached dynamic equilibrium? A The equilibrium constant K is equal to 1. B The reaction between the acid and the alcohol has stopped. C The concentrations of the products equal those of the reactants. D The rate of production of ethyl ethanoate equals its rate of hydrolysis. 16 The graph below show s the percentage of products present at equilibrium over a range of temperatures and pressures. Which of the following reactions could the graph represent? A C(s) + O2(g) ⇌ 2CO(g) ΔH = ‒99 kJ mol‒1 B H2(g) + I2(g) ⇌