ASRJC 2026 Prelim P3 QP

ASRJC JC2 PRELIM 2026 9476/03/H2 [Turn over ANDERSON SERANGOON JUNIOR COLLEGE 2026 JC 2 PRELIMINARY EXAMINATION NAME:______________________________ ( ) CLASS: 26 / _____ CHEMISTRY 9476/03 Paper 3 Structured Questions 28 August 2026 2 hours You must answer on the question paper. You will need: Data Booklet. INSTRUCTIONS • Section A: answer all questions. • Section B: answer one question. • Use a black or dark blue pen. You may use a pencil for any diagrams or graphs. • Write your name, class and register number on the blanks at the top of the page. • Write your student ID on the right. Using a dark pencil, completely shade the corresponding circles for the digit or letter in each column. Cleanly erase any mistakes. • Write your answer to each question in the space provided. • Do not use an erasable pen. Do not use correction fluid or tape. • You may use an approved calculator. INFORMATION • The total mark for this paper is 75. • The number of marks for each question or part question is shown in brackets [ ]. For Examiner’s Use Paper 3 A1 /22 A2 /14 A3 /19 *B4 /20 *B5 /20 Total /75 *Circle the question you have attempted This document has 28 pages. Any blank pages are indicated.

2 ASRJC JC2 PRELIM 2026 9476/03/H2 Do not write in margin Section A Answer all the questions in this section in the spaces provided. 1 (a) Nickel is found in the d-block of the Periodic Table. Explain why nickel is described as a transition element. ……………………………………………………………………………………………………... …………………………………………………………………………………………………..[1] (b) Transition elements form stable complex ions in aqueous solution. When water ligands in a hydrated metal ion are substituted by other ligands, the equilibrium constant for the reaction is referred to as stability constant , Kstab, of the new complex. For example: [Ni(H2O)6]2+(aq) + 6NH3(aq) [Ni(NH3)6]2+(aq) + 6H2O(l) Kc = Kstab = 2+ 36 2+ 6 2 6 3 [Ni(NH ) ] [Ni(H O) ][NH ] Table 1.1 lists the Kstab of three nickel(II) complexes at 25 °C. Table 1.1 complex ligand Kstab [Ni(NH3)6]2+ NH3 5.0 × 107 [Ni(EDTA)]2− EDTA4− 4.0 × 1018 [Ni(en)3]2+ en 2.0 × 1018 “en” is the abbreviation for ethylenediammine, H2NCH2CH2NH2. (i) Predict, with the aid of an equation, how entropy will change when [Ni(EDTA)]2− is formed from [Ni(H2O)6]2+. Explain your answer. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………[2] (ii) Write an expression for the Kstab of the [Ni(EDTA)]2− complex ion. [1]

3 ASRJC JC2 PRELIM 2026 9476/03/H2 [Turn over Do not write in margin (iii) Deduce an expression for the Kc for the following equilibrium in terms of Kstab of the complexes involved. Hence, calculate the value of Kc and include the units. [Ni(NH3)6]2+(aq) + EDTA4−(aq) [Ni(EDTA)]2−(aq) + 6NH3(aq) [2] (iv) Name the type of isomerism displayed by [Ni(en)3]2+. Draw relevant 3-dimensional structures to explain your answer, showing clearly the atoms involved in bonding. You can use N N to represent the ligand, en. [2]

4 ASRJC JC2 PRELIM 2026 9476/03/H2 Do not write in margin (c) Copper forms numerous compounds such as copper(II) sulfate and copper oxides which are widely used in agriculture as fungicides and soil additives. When copper(II) sulfate, CuSO4, dissolves in water, a blue solution A is formed. Fig. 1.1 shows some reactions of solution A. Fig. 1.1 (i) Identify the species present in A, B and C. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………[2] (ii) Explain how B and C are formed. For each reaction that occurs, identify the type of reaction and write relevant chemical equation(s). ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………[3] (iii) Suggest why there are different numbers of ligands surrounding the Cu 2+ ion in A and [CuCl4]2−. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………[1] blue solution A blue solid B dark blue solution C yellow solution [CuCl4]2− NH3(aq) excess NH3(aq) concentrated HCl

5 ASRJC JC2 PRELIM 2026 9476/03/H2 [Turn over Do not write in margin (d) Fig. 1.2 shows the energy levels of the five 3d orbitals in Cu 2+ as an isolated gaseous species and Cu2+ in the tetrahedral complex ion [CuCl4]2−. Fig. 1.2 (i) Explain the relative energy levels of the 3d orbitals of Cu2+ in [CuCl4]2−. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………[2] (ii) Explain the origin of the yellow colour of [CuCl4]2−. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………[3]

6 ASRJC JC2 PRELIM 2026 9476/03/H2 Do not write in margin (e) Iron(II) hydroxide, Fe(OH)2, is sparingly soluble in water and has a Ksp value of 7.9 × 10−15 at 298 K. (i) Write the expression for Ksp Fe(OH)2. [1] (ii) Calculate the pH of a saturated solution of Fe(OH)2. [2] [Total: 22]

7 ASRJC JC2 PRELIM 2026 9476/03/H2 [Turn over Do not write in margin 2 (a) Compound N can be synthesised from bromobenzene using the route shown in Fig. 2.1. Br step 1 Br step 2 Br O [O] step 3 J K L step 4 M step 5 Br OH OO N CH3CH2OH, conc. H2SO4, heat Fig. 2.1 (i) Suggest the type of reaction and the reagents and conditions for step 1. ……………………………………………………………………………………………… ……………………………………………………………………………………………[2] (ii) Step 2 is an oxidation reaction. Write an equation for the reaction in step 2. Use [O] to represent oxygen from the oxidising agent. [1] (iii) Suggest structures for the organic compounds L and M. [2] (iv) Suggest reagents and conditions for step 3. ……………………………………………………………………………………………[1]

8 ASRJC JC2 PRELIM 2026 9476/03/H2 Do not write in margin (b) Separate samples of three organobromine compounds are added to warm AgNO3(aq). Br Br Br O P Q R State the expected observations, if any. Explain your answer. ……………………………………………………………………………………………………... ……………………………………………………………………………………………………... ……………………………………………………………………………………………………... ……………………………………………………………………………………………………... ……………………………………………………………………………………………………... ……………………………………………………………………………………………………... ……………………………………………………………………………………………………... ……………………………………………………………………………………………………... ……………………………………………………………………………………………………... ……………………………………………………………………………………………………... ……………………………………………………………