2021 DHS H2 Prelim Paper 1 Questions

© DHS 2021 9729/01 [Turn over Name: Centre/Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination Year 6 H2 CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 9729/01 27 September 2021 1 hour READ THESE INSTRUCTIONS FIRST Write your centre number, index number, name and class at the top of this page. Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. 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. This document consists of 15 printed pages and 1 blank page.

2 © DHS 2021 9729/01 2 Use of the Data Booklet is relevant to this question. The table shows the fifth, sixth, seventh, eighth, ninth and tenth ionisation energies of an element (Z ≤ 20) in the Periodic Table. 5th 6th 7th 8th 9th 10th ionisation energy / kJ mol–1 7975 9590 11343 14944 16964 48610 What can be inferred about the element from the above data? A It is in Group 2 of the Periodic Table. B It is in the third period of the Periodic Table. C Its 6th and 7th electrons are removed from different subshells. D It is likely to form an ionic compound when reacted with oxygen. 3 Which pair has the same shape? A BeCl2 and SO2 B CO2 and I3− C NO3− and PH3 D PO43− and SF4 1 Which ion has the same number of electrons and neutrons as Re3+75187? A W2+74182 B W+74186 C Os4+76188 D Os3+76189

3 © DHS 2021 9729/01 [Turn over 4 Which lattice structure is correctly described? lattice structure description A giant molecular lattice of molecules held together by strong covalent bonds B giant ionic each cation is only bonded to the anion to which electrons are transferred C giant metallic all electrons are delocalised within the metal cation lattice D simple molecular molecules held together by weak intermolecular forces 5 A gaseous sample containing x dm3 of gaseous methanol was burnt in 4x dm3 of oxygen to produce carbon dioxide and water vapour. The total pressure in the system after combustion was P. Which statement(s) is/are correct? 1 Methanol reacts with oxygen in a 2 : 3 mole ratio. 2 The partial pressure of carbon dioxide in the system is 0.18P. 3 Assuming these gases behave ideally, they occupy an insignificant volume. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only 6 The s– and p–block elements in Period 4 show a similar pattern of properties to the elements in Period 3. On this basis, which prediction can be made about element 33, arsenic? A Arsenic has a higher electronegativity than selenium. B Arsenic has a highest oxidation state of +6. C Chlorides of arsenic react with water to form acidic solutions. D Oxides of arsenic react with water readily to form hydroxides.

4 © DHS 2021 9729/01 7 J, K and L are Group 2 elements. The table below shows the observations when dilute sulfuric acid is added separately to carbonates of J, K and L. metal carbonate addition of sulfuric acid J White precipitate K White precipitate L Colourless solution Carbonate of K decomposes at a higher temperature than that of J. Which could be the identities of J, K and L? J K L A Ba Ca Mg B Mg Ba Ca C Ca Ba Mg D Ba Mg Ca 8 Which property increases down Group 17 elements or their hydrides? A acidity of the hydrides B oxidising power of the elements C colour intensity of the hydrides D volatility of the elements

5 © DHS 2021 9729/01 [Turn over 9 The enthalpy change of formation of cobalt(II) chloride can be calculated using a Born–Haber cycle. The relevant enthalpy changes are shown in the table. enthalpy change/ kJ mol−1 Cl2(g) ® 2Cl(g) +244 Cl(g) + e− ® Cl−(g) −355 Co(s) ® Co(g) +427 Co(g) ® Co+(g) + e− +757 Co+(g) ® Co2+(g) + e− +1640 Co2+(g) + 2Cl−(g) ® CoCl2(s) −2671 What is the enthalpy change of formation of CoCl2? A +42 kJ mol−1 B −69 kJ mol−1 C −202 kJ mol−1 D −313 kJ mol−1 10 Use of the Data Booklet is relevant to this question. The enthalpy change of solution for sodium bromide and magnesium bromide are –18 kJ mol–1 and –216 kJ mol–1 respectively. Which statement(s) is/are correct? 1 The enthalpy change of hydration of sodium ion is more exothermic than that of magnesium ion. 2 The lattice energy of sodium bromide is less exothermic than that of magnesium bromide. 3 Sodium bromide is likely to be less soluble than magnesium bromide. A 1 and 3 only B 1 and 2 only C 2 and 3 only D 3 only

6 © DHS 2021 9729/01 11 In the first step of the Contact Process, sulfur dioxide is converted to sulfur trioxide in the presence of a catalyst, vanadium(V) oxide, V2O5. SO2 + V2O5 → SO3 + V2O4 In this reaction, how many moles of electrons were transferred per mole of V2O5? A 1 B 2 C 2.5 D 3 12 The reaction between gaseous NO2 and CO follows the mechanism shown below. Step 1: 2NO2 → NO3 + NO (slow) Step 2: NO3 + CO → NO2 + CO2 Which statement(s) is/are true about the kinetics of this reaction? 1 Increasing the partial pressure of CO in the reaction vessel has no effect on the rate. 2 Step 1 has a higher activation energy and a smaller rate constant than step 2. 3 The rate constant of the reaction has the units mol–2 dm6 s–1. A 1 only B 1 and 2 only C 2 and 3 only D 1 and 3 only

7 © DHS 2021 9729/01 [Turn over 13 The decomposition of aqueous hydrogen peroxide is a first order reaction. Which graph correctly describes the kinetics of this reaction? A B C D [H2O2] time rate time rate [H2O2] rate [H2O2]

8 © DHS 2021 9729/01 14 1 mol of N2O4 and 0.2 mol of NO2 were added to a sealed vessel of fixed volume at 298 K. When the system reached equilibrium, 0.68 mol of NO2 was present in the vessel. N2O4(g) ⇌ 2NO2(g) Which statement(s) is/are true about this equilibrium? 1 0.76 mol of N2O4 are present at equilibrium. 2 The value for the equilibrium constant, Kc, is 0.608. 3 The pressure in the vessel at equilibrium is lower than the pressure before the reaction started. A 1 only B 2 and 3 only C 1 and 2 only D 1 and 3 only 15 Consider the reaction between nitrogen and oxygen to form nitrogen monoxide. N2(g) + O2(g) ⇌ 2NO(g) ∆H = +181 kJ mol–1 Which of the following changes will result in rightward shift in the equilibrium position but not a change in the rate constant of the forward reaction? A Adding a heterogeneous catalyst B Increasing the temperature of the reaction mixture C Increasing the partial pressure of the nitrogen gas D Reducing the volume of the reaction vessel

9 © DHS 2021 9729/01 [Turn over 16 Methylamine, CH3NH2, has a pKb of 3.3. 25.0 cm3 of 0.1 mol dm–3 CH3NH2 was added to a conical flask. It was then titrated against 0.1 mol dm–3 HCl. Which statement is true about the pH of the solution before the addition of HCl and after adding 13.00 cm3 of HCl? Before addition of HCl After adding 13.00 cm3 of HCl A Less than 13 Slightly less than 10.7 B Less than 13 Slightly more than 10.7 C 13 Slightly less than 10.7 D 13 Slightly more than 10.7 17 Magnesium hydroxide, Mg(OH)2, has a Ksp value of 1.8 × 10–11 at 25 °C. In which 0.1 mol dm–3 solution will Mg(OH)2 have the highest and lowest solubility? Highest solubility Lowest solubility A KNO3(aq) MgCl2(aq) B KNO3(aq) NaOH(aq) C CH3COOH(aq) MgCl2(aq) D CH3COOH(aq) NaOH(aq)

10 © DHS 2021 9729/01 18 Which statement(s) is/are true about the molecule below? 1 The molecule can act as a nucleop