Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Chemical Tests
68 practice questions
Topics covered
Practice questions
1–9 of 9 · Hard
Question 1
2 marks · Hard
Answer and see the solution →A colourless liquid is suspected to contain water, but may also have dissolved salts. You are given a thermometer and a Bunsen burner. State how you would use these to test for the purity of the water and describe what result confirms that it is pure.
Question 2
5 marks · Hard
Answer and see the solution →A student is given three unknown gases: Gas A, Gas B, and Gas C. She is told that one may be ammonia, another is hydrogen, and the third is chlorine. She uses damp red litmus paper to test each gas.
(a)[1 mark]State what is observed when damp red litmus paper is placed in ammonia gas.
(b)[1 mark]Describe what happens to damp red litmus paper when it is exposed to chlorine gas.
(c)[2 marks]Explain why ammonia is the only alkaline gas among the three.
(d)[1 mark]Suggest an additional chemical test to identify hydrogen, apart from using litmus paper. State what result confirms hydrogen is present.
Question 3
2 marks · Hard
Answer and see the solution →A student performs a test for water using anhydrous copper(II) sulfate. The white powder turns blue when a sample liquid is added. State what this test does and does not show about the sample.
Question 4
2 marks · Hard
Answer and see the solution →A student is given a solution that may contain sodium carbonate. Describe two distinct observations the student would expect to make when dilute hydrochloric acid is added to this solution if carbonate ions are present.
Question 5
5 marks · Hard
Answer and see the solution →You are given a solid sample labelled 'unknown.' It could be one of the following: magnesium sulfate, sodium carbonate, or potassium chloride.
(a)[2 marks]Describe how you would carry out a chemical test to determine whether this solid contains carbonate ions. Include the reagents and apparatus you would use.
(b)[1 mark]Suppose the unknown is sodium carbonate. Write the ionic equation for its reaction with hydrochloric acid.
(c)[2 marks]Explain how you would confirm that the gas produced in the reaction is carbon dioxide.
Question 6
2 marks · Hard
Answer and see the solution →A solution of potassium carbonate is added to excess dilute nitric acid in a test tube. The student's teacher tells them to test any gas produced with limewater. Explain why limewater is used in this test and state the result that shows carbonate ions were present.
Question 7
2 marks · Hard
Answer and see the solution →Explain why nitric acid must be added before silver nitrate when testing a solution for halide ions. Include what could happen if this step is skipped or done in the wrong order.
Question 8
5 marks · Hard
Answer and see the solution →When silver nitrate solution is added to separate solutions of sodium chloride, sodium bromide and sodium iodide (each has first been acidified with dilute nitric acid), different precipitates form.
(a)For each solution, name the precipitate formed and state its colour.
(i)[1 mark]Sodium chloride solution:
(ii)[1 mark]Sodium bromide solution:
(iii)[1 mark]Sodium iodide solution:
(b)Give the chemical formula for the precipitate formed in each case.
(i)[1 mark]From sodium chloride:
(ii)[1 mark]From sodium iodide:
Question 9
2 marks · Hard
Answer and see the solution →Describe the steps you would take to test a solution to determine whether it contains any halide ions (chloride, bromide, or iodide) using silver nitrate.