Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Testing for carbonates (CO3^2-)
20 practice questions
Practice questions
1–9 of 9 · Normal
Question 1
4 marks · Normal
Answer and see the solution →A student tests a solid substance to find out if it contains carbonate ions. The student adds dilute sulfuric acid and observes bubbles of gas. They collect the gas and pass it through limewater.
(a)[1 mark]Write the ionic equation for the reaction between carbonate ions () and sulfuric acid.
(b)[1 mark]State the identity of the gas formed.
(c)[1 mark]Describe the observed result when the gas is bubbled through limewater.
(d)[1 mark]Explain how these observations confirm that the original solid contained carbonate ions.
Question 2
4 marks · Normal
Answer and see the solution →A student is testing three white powders (A, B and C) for carbonate ions using dilute hydrochloric acid and limewater. Their results are shown:
Student's results for carbonate test Powder Acid added Fizzing observed? Limewater turns cloudy? A Yes Yes Yes B Yes No No C Yes Yes No (a)[2 marks]Which powder(s) definitely contain carbonate ions? Explain your answer.
(b)[2 marks]Suggest a reason why powder C showed fizzing but did not turn limewater cloudy.
Question 3
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 4
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 5
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 6
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 7
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 8
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 9
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.)