XMS SEC 3 WA2 2023 QP

3 6092/Chemistry/2023 Term 2 Weighted Assessment Section A Answer all questions. Write your answers in the boxes provided at the end of the Section. 1 Which of the following elements would be expected to form the largest ion (most number of electron shells) with a noble gas configuration? A oxygen B fluorine C potassium D magnesium 2 Element P has an electronic configuration of 2.8.8.2. Element Q has an electronic configuration of 2.8.7. What is the likely chemical formula of the compound containing only P and Q? A P7Q2 B PQ2 C P2Q D PQ 3 A piece of zinc strip is burnt in oxygen to form zinc oxide. Which of the following chemical equation is correct? A 2Zn + O2 → 2ZnO B 2Zn + O → Zn2O C Zn + O2 → ZnO2 D Zn + O → ZnO

4 6092/Chemistry/2023 Term 2 Weighted Assessment 4 Which particles enable the conduction of electricity through metals? A positive ions and electrons B positive ions and negative ions C positive ions only D electrons only 5 Which chemical equation is not balanced? A C6H12O6 + 3O2 → 6CO2 + 6H2O B 2HCl + CaCO3 → CaCl2 + CO2 + H2O C 2KClO3 → 2KCl + 3O2 D 4P + 5O2 → 2P2O5 Question 1 2 3 4 5 Answer

5 6092/Chemistry/2023 Term 2 Weighted Assessment For Examiner’s Use Section B Answer all questions. Write your answers in the spaces provided. 6 Balance the following chemical equations. (a) ………. S8 + ………. O2 → ………. SO3 [1] (b) ………. C3H8 + ………. O2 → ………. CO2 + ………. H2O [1] (c) ………. AlBr3 + ………. K2SO4 → ………. KBr + ………. Al2(SO4)3 [1] [Total: 3 marks] 7 Scandium is a metallic element with the symbol Sc and atomic number 21. (a) Describe the structure of a piece of scandium. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. [2] (b) Scandium oxide has the chemical formula Sc2O3. Write the chemical formula of scandium sulfate and scandium hydroxide. (i) scandium sulfate …………………………………. [1] (ii) scandium hydroxide …………………………………. [1] [Total: 4 marks]

6 6092/Chemistry/2023 Term 2 Weighted Assessment For Examiner’s Use 8 Carbon is a highly versatile element that exists in different forms such as diamond, graphite and fullerene. Figure 7.1 shows the structure of graphite. Figure 7.1 An example of fullerene is the buckyball, which consists of 60 carbon atoms, covalently bonded in a cage -like structure (made of twenty hexagons and twelve pentagons), and resembles a soccer ball. Figure 7.2 belows shows the structure of a buckyball,C60. Figure 7.2 Flat layer of carbon atoms. Each carbon atom in graphite is joined to only three other carbon atoms. Weak forces held the layers of carbon atoms together. Strong bonds exist between carbon atoms in a layer. Flat layer of carbon atoms. Flat layer of carbon atoms. Flat layer of carbon atoms. carbon atom pentagon hexagon covalent bond

7 6092/Chemistry/2023 Term 2 Weighted Assessment For Examiner’s Use 8 (a) State a physical property of graphite. …………………………………………………………………………………………. …………………………………………………………………………………………. [1] (b) By comparing the structures of graphite and buckyball, predict if buckyball can conduct electricity. Explain your answer. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. [2] [Total: 3 marks]

8 6092/Chemistry/2023 Term 2 Weighted Assessment For Examiner’s Use Section C Answer all questions. Write your answers in the spaces provided. 9 Read the information about the chlorides of elements in Period 3 of the Periodic Table. Elements and their chlorides The formulae and chemical properties of the chlorides of the elements change across Period 3 (from sodium to argon). The chlorides behave differently when they are added to water. Some of the chlorides dissolve in water to form a solution. Some hydrolyse when they are added to water. This means that they react chemically with water to produce new products (refer to Table 9.1 below). Element metal / non-metal formula of main chloride bonding in chloride effect of adding chloride to water products of adding chloride to water Na metal NaCl ionic dissolves NaCl(aq) Mg metal MgCl2 ionic dissolves MgCl2(aq) Al metal AlCl3 covalent hydrolyses complex mixture of products including HCl(aq) Si non-metal SiCl4 covalent hydrolyses SiO2 (s) HCl(aq) P non-metal PCl3 covalent hydrolyses H3PO3(aq) HCl(aq) S non-metal S2Cl2 covalent hydrolyses complex mixture of products including HCl(aq) Cl non-metal Cl2 covalent hydrolyses HClO(aq) HCl(aq) Table 9.1 The chlorides have different formulae and the ratio of the element to chlorine changes across Period 3. Some examples are shown in the table below. formula of chloride ratio of element to chlorine NaCl 1 : 1 MgCl2 1 : 2 AlCl3 1 : 3 Table 9.2

9 6092/Chemistry/2023 Term 2 Weighted Assessment For Examiner’s Use 9 (a) Describe the trend for the ratio of each element to chlorine across Period 3. Include ratios in your answer. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. [2] (b) Two students talk about the data. Student 1: ‘I think that whether or not the chloride hydrolyses is linked to the metal or non-metal character of the element.’ Student 2: ‘I think that whether or not the chloride hydrolyses is linked to the bonding of the chloride.’ Does the information in Table 9.1 support the ideas of the students? Explain your reasoning. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. [3] (c) Suggest a reason why argon is not included in Table 9.1 of information about Period 3 chlorides. …………………………………………………………………………………………. [1]

10 6092/Chemistry/2023 Term 2 Weighted Assessment For Examiner’s Use 9 (d) Using information from Table 9.1 write a balanced equation, including state symbols, for the reaction of chlorine gas with water. …………………………………………………………………………………………. [2] (e) (i) Draw ‘dot-and-cross’ diagram (show outer electrons only) to show the bonding in a molecule of chlorine. (ii) Complete the following ‘dot-and-cross’ diagram (show outer electrons only) to show the bonding in a molecule of disulfur chloride, S2Cl2. key × electron of chlorine • electron of sulfur [2] [2] [Total: 12 marks] S S Cl Cl

11 6092/Chemistry/2023 Term 2 Weighted Assessment For Examiner’s Use 10 The table shows some information about the properties of compounds Li2O and CH4. compound melting point / C boiling point / C solubility in water electrical conductivity at room temperature and pressure Li2O 1438 2600 soluble poor CH4 −182 −162 insoluble poor (a) Draw ‘dot-and-cross’ diagram (show outer electrons only) for Li2O. [2] (b) What are the physical states of compounds Li2O and CH4 at room temperature and pressure? Li2O : …………………………………………………. CH4