2024 JPJC Prelim P2 Question paper

© Jurong Pioneer Junior College [Turn Over NAME CLASS 23S JURONG PIONEER JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION 2024 CHEMISTRY 9729/02 Paper 2 Structured Questions 10 September 2024 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, class and index number in the spaces at the top of this page. Write in dark blue or black pen. You may use a HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 7 2 11 3 13 4 14 5 12 6 18 Penalty (delete accordingly) Lack 3 sf in final answer –1 / NA Missing/wrong units in final ans –1 / NA Bond linkages –1 / NA Total 75 This document consists of 22 printed pages and 2 blank pages.

2 © Jurong Pioneer Junior College 9729/02/J2 PRELIMINARY EXAM/2024 Answer ALL the questions in the spaces provided. 1 Use of the Data Booklet is relevant to this question. The most recent updates to the Periodic Table occurred in 2016, when IUPAC officially recognised the discovery of four new elements: Nihonium (Nh), Moscovium (Mc), Tennessine (Ts), and Oganesson (Og), completing the seventh row of the table. Table 1.1 lists the number of protons, neutrons and electrons in four particles, each from one of the elements mentioned above. Each particle may be an atom, an anion or a cation. Table 1.1 element particle atomic no. nucleon no. no. of protons no. of neutrons no. of electrons Nihonium (Nh) Nh 113 286 113 173 113 Moscovium (Mc) Mc3− 115 290 175 118 Tennessine (Ts) Ts− 117 177 Oganesson (Og) Og 294 118 118 For Examiner’s Use (a) Based on the positions of the four new elements in the Periodic Table, state the Group that each of the elements belong to. Nh …………………… Mc …………………… Ts …………………… Og …………………… [1] (b) Fill in the empty spaces in Table 1.1. [2] (c) A stream consisting of -particles (He2+) is subjected to an electric field as shown in Fig. 1.1 below. Fig. 1.1 Determine, by calculation, the angle of deflection for a second stream consisting of Mc3- that is passed through the same electric field. + − -rays Source 80o

3 © Jurong Pioneer Junior College 9729/02/J2 PRELIMINARY EXAM/2024 [Turn Over …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… ……………………………………………………………………………………… [1] For Examiner’s Use (d) The simplified electronic configuration of Nihonium is given below. Nh: [Rn] 5f14 6d10 7s2 7p1 (i) Using information from Table 1.1 , give the simplified electronic configuration of Moscovium (Mc). …………………………………………………………………………………… …………………………………………………………………………………… [1] (ii) Predict if Nh or Mc would have a higher first ionisation energy. Briefly explain your answer. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… [2] [Total: 7]

4 © Jurong Pioneer Junior College 9729/02/J2 PRELIMINARY EXAM/2024 0 0.001 0.002 0.003 0.004 0.005 0.006 0 20 40 60 80 100 120 140 160 180 200 2 (a) Catalytic converters containing platinum solid convert over 90% of carbon monoxide and gaseous nitrogen oxides into harmless gases such as CO 2 and N2. Outline the mode of action of the platinum catalyst. For Examiner’s Use ………………………………………………………………………………………….. ………………………………………………………………………………………….. …………………………………………………………………………..……………… …………………………………………………………………………….…….……… …………………………………………………………………………..……………… [2] One reaction in which air can be polluted with nitrogen oxides is shown below. 2NO(g) + O2(g) → 2NO2(g) 0.05 mol dm -3 of NO and 0.005 mol dm -3 of O 2 were mixed and the rate of reaction was followed by measuring the concentration of oxygen remaining after various time intervals. The following graph was obtained in Fig. 2.1. (b) (i) Define the term half-life of a reaction. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… [1] [O2] / mol dm-3 Time/ s Fig. 2.1

5 © Jurong Pioneer Junior College 9729/02/J2 PRELIMINARY EXAM/2024 [Turn Over (ii) Show all your working and draw clearly any construction lines on Fig. 2.1 to determine the order of reaction with respect to O2. For Examiner’s Use …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… [2] (iii) Show all your working and clearly draw any construction lines on Fig. 2.1 to determine the initial rate of reaction. State its units. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… [2] (c) Further experiments were carried out changing the [NO] but keeping the initial [O2] constant at 0.10 mol dm-3. The following results were obtained. Table 2.1 Experiment Initial [NO] / mol dm-3 Initial rate / mol dm-3 min-1 1 0.01 3.75 x 10-5 2 0.02 1.50 x 10-4 (i) Using the data from Table 2.1, deduce the order of reaction with respect to NO. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… [1] (ii) Write the rate equation for this reaction. …………………………………………………………………………………… …………………………………………………………………………………… [1]

6 © Jurong Pioneer Junior College 9729/02/J2 PRELIMINARY EXAM/2024 (iii) Using Table 2.1, calculate a value for the rate constant. Include units of the rate constant in your answer. For Examiner’s Use …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… [1] (d) Two possible mechanisms for this reaction are given below. State the mechanism which is consistent with the rate equation you have written in (c)(ii) and explain your answer. Mechanism 1 2NO ⇌ N2O2 (fast) N2O2 + O2 → 2NO2 (slow) Mechanism 2 NO + O2 → NO2 + O (slow) O + NO → NO2 (fast) …………………….…………………………………………………………………… ………………….……………………………………………………………………… …………………………………………………………………………………………. ……………….………………………………………………………………………… ………………….……………………………………………………………………… …………………………………………………………………………………………. ……………………………….………………………………………………………… …………………………………….…………………………………………………… [1] [Total: 11]

7 © Jurong Pioneer Junior College 9729/02/J2 PRELIMINARY EXAM/2024 [Turn Over 3 The Wolff-Kishner reaction transform s ketones or aldehydes into alkanes by using hydrazine, N₂H₄ and potassium hydroxide, KOH, as illustrated in equation 1 below. C O R R N N H H H H KOH N2++ C HR HR + H2O For Examiner’s Use (a) State the type of reaction in equation 1. ………………………………………………………………………………………… [1] (b) Indane, C 9H10, is an ortho-fused bicyclic hydrocarbon consisting of a benzene ring fused to a cyclopentane ring. It is used as an anti-vibration age