CHIJ 4NA Sci (Chem) Prelim 2023_P4

Index Number Class Name CHIJ ST JOSEPH’S CONVENT PRELIMINARY EXAMINATIONS NA SCIENCE (CHEMISTRY) Paper 4 Chemistry Secondary 4 Normal (Academic) NA 5105/04 5107/04 Thursday, 27 July 2023 Paper 3 and 4: 1 hour and 15 minutes READ THESE INSTRUCTIONS FIRST Write your index number, class and name on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs or rough working Do not use staples, paper clips highlighters, glue or correction fluid. Paper 4: Answer all questions in Section A and any two questions in Section B. The use of an approved scientific calculator is expected, where appropriate. In calculation, you should show all the steps in your working, giving your answer at each stage. You are advised to spend no longer than 30 minutes on Paper 3. You may proceed to answer Paper 4 as soon as you have completed Paper 3. A copy of the Periodic Table is printed on page 14. At the end of the examination hand in your answers to Paper 3 and Paper 4 separately. The number of marks is given in brackets [ ] at the end of each question or part question. FOR EXAMINER’S USE Paper 3 / 20 Paper 4 / 30 TOTAL / 50 This document consists of 14 printed pages.

2 Section A (14 marks) Answer all questions in the spaces provided. 1 Substances may be described as containing A a pure element, B a pure compound, C a mixture of elements, D a mixture of compounds. Complete the table by writing the letter corresponding to the most appropriate description for each of the substances listed. The first one has been completed for you. substance description carbon dioxide B water bitumen steel [2] [Total: 2]

3 2 Magnesium chloride can be used as a mineral supplement to prevent and treat low amounts of magnesium in the blood. (a) State the formula of magnesium chloride. ……………………………………………………………………………….. [1] (b) Describe, in terms of electrons, how a chlorine atom becomes a chloride ion. ……………………………………………………………………………….. ……………………………………………………………………………….. [1] (c) Magnesium chloride has a high melting point. Explain this using the structure and bonding found in magnesium chloride. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. [2] [Total: 4]

4 3 Some gases found in air pollute the environment. (a) Complete the table to show one major source of the atmospheric pollutant in the table. Table 3.1 atmospheric pollutant source carbon dioxide combustion of fossil fuels sulfur dioxide [1] (b) Sulfur dioxide dissolves in raindrops to produce ‘acid rain’. (i) Write a word equation to show the conversion of the sulfur dioxide in a raindrop into a compound that causes acid r