NAS 2026 Chem Prelim P2 QP

Name: ...................................................................... Register no: ........... Class: ............. NGEE ANN SECONDARY SCHOOL O PRELIMINARY EXAMINATION CHEMISTRY 6092/02 Paper 2 26 August 2026 1 h 45 min Additional Materials: NIL READ THESE INSTRUCTIONS FIRST Write your name, register number and class at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions. Write your answers in the spaces provided. Section B Answer one questions. Write your answers in the spaces provided. The number of marks is given in brackets [ ] at the end of each question or part question. A copy of the Periodic Table is printed on page 26. The use of an approved scientific calculator is expected, where appropriate. Checked by student: ____________________ Date: _________ This document consists of 25 printed pages and 1 blank pages. For Examiner’s Use Section Marks A /50 B /30 Total /80

2 NAS/2026/Prelim/4E/CHEMISTRY(6092) Section A Answer all questions. 1 This question is about the elements in Group 1 and Group 17 of the Periodic Table. (a) Elements in Group 1 and Group 17 show certain trends down the group. Which trends are only true for Group 1, which trends are only true for Group 17 and which trends are true for both? Put a tick() in one box in each row. trend down the group only true for Group 1 only true for Group 17 true for both The number of electron shells increases. The density increases. The reactivity increases. The colour intensity of the elements increases. [2] (b) A jet of fluorine gas is aimed at a filter paper soaked in a solution of potassium iodide. The solution on the filter paper quickly turns brown. Explain why the solution turns brown. ………………………………………………………………………………………………………... ………………………………………………………………………………………………………... ……………………………………………………………………………………………………...[2] [Total: 4]

3 NAS/2026/Prelim/4E/CHEMISTRY(6092) 2 The most common isotope of hydrogen is H11 . Hydrogen has another isotope called deuterium which has the symbol H12 . This isotope is given the symbol D. (a) (i) Explain, in terms of atomic structure, why the atoms of H11 and H12 are isotopes. ………………………………………………………………………………………………… ………………………………………………………………………………………………… …………………………………………………………………………………………….. [1] (ii) Explain why the two isotopes of hydrogen have identical chemical properties. ………………………………………………………………………………………………… …………………………………………………………………………………………….. [1] (b) In Experiment 1, concentrated hydrochloric acid, HCl(aq) is placed at one end of a tube, and concentrated ammonia solution, NH3(aq) is placed at the other end. Gaseous HCl and NH3 diffuse from each end. When the gases meet, they react and a white ring of solid ammonium chloride, NH4Cl, appears, as shown in Fig. 2.1. Fig. 2.1 (i) The solid ammonium chloride obtained is dissolved in water to form a solution. Describe how you would carry out a test to show the presence of ammonium ions in the solution. ………………………………………………………………………………………………… ………………………………………………………………………………………………… …………………………………………………………………………………………….. [1]

4 NAS/2026/Prelim/4E/CHEMISTRY(6092) (ii) Fig. 2.2 shows the position of the ring of ammonium chloride formed in Experiment 1. Experiment 2 is performed using the same tube and same temperature, with the concentrated NH3(aq) being replaced with concentrated ND3(aq), shown in Fig. 2.3. Gaseous HCl and ND3 react to form a white ring of solid, ND4Cl. Experiment 1 Fig. 2.2 Experiment 2 Fig. 2.3 On Fig 2.3, draw the likely position of the ND4Cl formed in Experiment 2. Explain your answer. ………………………………………………………………………………………………… ………………………………………………………………………………………………… …………………………………………………………………………………………….. [2] [Total: 5] cotton wool soaked in concentrated NH3(aq) ring of ammonium chloride formed in Experiment 1 cotton wool soaked in concentrated HCl(aq) cotton wool soaked in concentrated ND3(aq) cotton wool soaked in concentrated HCl(aq)

5 NAS/2026/Prelim/4E/CHEMISTRY(6092) 3 A student compared the action of heat on three solid metal carbonates. She heated each carbonate using the apparatus shown in Fig. 3.1 and recorded the time taken for the limewater to form a white precipitate. Fig. 3.1 The results for each of the carbonates are shown in Table 3.1. Table 3.1 metal carbonate time taken for white precipitate to form in limewater / s copper(II) carbonate 10 magnesium carbonate 40 zinc carbonate 24 (a) Explain the results in Table 3.1 in terms of the reactivity of copper, magnesium and zinc. ……………………………………………………………………………..…………………………. ………………………………………………………………………………………………………... ………………………………………………………………………………………………………... ………………………………………………………………………………………………………... ……………………………………………………………………………………………………...[2]

6 NAS/2026/Prelim/4E/CHEMISTRY(6092) (b) The student conducted another experiment with the three metal carbonates. She heated 2.00 g samples of each of the three carbonates strongly until there was no further change in mass. Metal carbonates may decompose on heating to form a solid metal oxide and carbon dioxide gas. Table 3.2 shows the mass of solid remaining at the end of the heating. Table 3.2 metal carbonate mass before heating / g mass after heating / g copper(II) carbonate 2.00 1.29 magnesium carbonate 2.00 0.95 zinc carbonate 2.00 1.30 (i) Calculate the mass of carbon dioxide formed when 2.00 g of copper(II) carbonate is heated. [1] (ii) The student carried out the same experiment with 2.00 g of sodium carbonate. Predict the mass of the solid remaining at the end of heating. …………………………………………………………………………………………………[1] [Total: 4]

7 NAS/2026/Prelim/4E/CHEMISTRY(6092) 4 Aldehydes are a homologous series of organic compounds. Unlike carboxylic acids, aldehydes are neutral compounds that do not ionise in water to release hydrogen ions. Table 4.1 shows the names, formulae and boiling points of some aldehydes. Table 4.1 name molecular formula structural formula boiling point / °C methanal CH2O –19 ethanal C2H4O 20 propanal C3H6O 49 butanal C4H8O 75 (a) Using the information in Table 4.1, state two characteristics of a homologous series. ………………………………………………………………………………………………………... ………………………………………………………………………………………………………... ……………………………………………………………………………………………………...[2] (b) Describe and explain the trend in boiling point of the aldehydes from methanal to butanal. ………………………………………………………………………………………………………... ………………………………………………………………………………………………………... ………………………………………………………………………………………………………... ……………………………………………………………………………………………………...[2] H C H C H O H H C O H C C H C H O H H H H C C H C H O H H H C H H H

8 NAS/2026/Prelim/4E/CHEMISTRY(6092) (c) Ethanal can be oxidised to form ethanoic acid. ethanal ethanoic acid (i) Name a reagent available in the laboratory that can oxidise ethanal to ethanoic acid. ………………………………………………………………………………...……………[1] (ii) Describe an observation when the reagent stated in (c)(i) is added to ethanal and the mixture is warmed. ………………………………………………………………………………………………… ………………………………………………………………………………...……………[1] (d) Ethanal reacts with a reagent, 2,4 -dinitrophenylhdrazine to form an orange precipitate as shown in Fig. 4.1. Fig. 4.1 State t