Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Testing for carbonates (CO3^2-)
20 practice questions
Practice questions
11–20 of 20
Question 11
1 mark · Normal
Answer and check →Which observation indicates the presence of carbonate ions when dilute hydrochloric acid is added to a solid sample?
- A.The sample turns blue
- B.A green precipitate forms
- C.Effervescence (bubbles of gas) occurs
- D.The temperature falls
Question 12
2 marks · Normal
Answer and see the solution →Complete these sentences about the test for carbonate ions. (1) When dilute acid is added to a carbonate compound, __________ is given off. (2) This gas can be tested using __________.
Question 13
4 marks · Normal
Answer and see the solution →A teacher places a small amount of white powder in a test tube and adds dilute nitric acid. Bubbles appear. To confirm the identity of the gas, another experiment is performed with limewater.
(a)[1 mark]Write the formula for the ion being tested.
(b)[1 mark]State the name and formula of the gas formed.
(c)[1 mark]Describe the chemical test for this gas.
(d)[1 mark]State the positive result for this test.
Question 14
2 marks · Normal
Answer and see the solution →Describe how you would test a solid sample to show that it contains carbonate ions (). State what you would observe if carbonate ions are present.
Question 15
2 marks · Normal
Answer and see the solution →State the substance you would add to a sample to test for carbonate ions, and describe what you would observe if carbonate ions are present.
Question 16
4 marks · Normal
Answer and see the solution →A student is given a white powder thought to contain carbonate ions.
(a)[1 mark]The student adds dilute hydrochloric acid to the powder.
State what the student should observe if carbonate ions are present.
(b)[1 mark]The student collects the gas given off and bubbles it through limewater. What result would confirm the gas is carbon dioxide?
(c)[2 marks]Write the ionic equation for the reaction between carbonate ions and hydrochloric acid.
Question 17
3 marks · Normal
Answer and see the solution →A student tests 0.30 g of potassium carbonate ([K\ce{K2CO3}) powder with excess dilute hydrochloric acid. All of the carbonate reacts.
(a)[1 mark]Write the chemical equation, including state symbols, for the reaction between potassium carbonate and hydrochloric acid.
(b)[1 mark]Calculate the number of moles of potassium carbonate in 0.30 g. (Relative formula mass, , of \ce{K2CO3} = 138.0.)
(c)[1 mark]Calculate the volume of carbon dioxide gas produced at room temperature and pressure (RTP), in cm. (1 mole of gas at RTP occupies 24 000 cm.)
Question 18
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 19
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 20
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.