AQA GCSE Chemistry (8462), Higher tier · Chemical analysis › Identification of ions
Practise Carbonates. 11 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
Required practical:Identifying ions (method, variables and exam tips)
Quick recall
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Name the gas produced when a carbonate reacts with an acid.
carbon dioxide
Balance the equation for the reaction. Na2CO3(s) + ....HCl(aq) → ....NaCl(aq) + H2O(l) + CO2(g)
Na2CO3 + 2HCl → 2NaCl + H2O + CO2
Write the ionic equation for the reaction between carbonate ions and hydrogen ions.
CO32− + 2H+ → CO2 + H2O
A white solid is a Group 1 carbonate with the formula M2CO3, where M is the Group 1 metal. A student added excess dilute hydrochloric acid to 1.00 g of the solid and collected the gas in a gas syringe. M2CO3(s) + 2HCl(aq) → 2MCl(aq) + H2O(l) + CO2(g) Volume of gas collected = 324 cm3 at room temperature and pressure. The volume of one mole of any gas at room temperature and pressure is 24.0 dm3. Relative atomic masses (Ar): Li = 7 C = 12 O = 16 Na = 23 K = 39 Calculate the amount in moles of carbon dioxide produced.
0.0135 mol
Calcium carbonate reacts with dilute hydrochloric acid. Name the salt formed in this reaction.
calcium chloride
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
(a) Describe the test for carbonate ions. Give the result of a positive test.[3]
(b) Name the gas produced when a carbonate reacts with an acid.[1]
Show the answer and mark scheme
(a)
add dilute acid (e.g. dilute hydrochloric acid)
bubbles / fizzing
the gas turns limewater milky / cloudy
(b)Answer: carbon dioxide
carbon dioxide / CO2
Question 2Medium4 marks
A student added dilute hydrochloric acid to a white solid, sodium carbonate.
(a) Balance the equation for the reaction. Na2CO3(s) + ....HCl(aq) → ....NaCl(aq) + H2O(l) + CO2(g)[1]
(b) Describe how the student could show that the gas produced is carbon dioxide. Give the result.[2]
(c) The student added dilute hydrochloric acid to a different white solid. There was no fizzing. What does this show about the solid?[1]
Show the answer and mark scheme
(a)Answer: Na2CO3 + 2HCl → 2NaCl + H2O + CO2
2HCl and 2NaCl
(b)
bubble the gas through limewater
limewater turns milky / cloudy
(c)
the solid is not a carbonate / does not contain carbonate ions
Question 3Hard6 marks
A student has three unlabelled white solids. The solids are calcium carbonate, sodium carbonate and sodium chloride.
(a) Describe how the student could use the test for carbonate ions to identify the sodium chloride.[2]
(b) Describe one test the student could then use to tell apart calcium carbonate and sodium carbonate. Give the results.[2]
(c) Write the ionic equation for the reaction between carbonate ions and hydrogen ions.[2]
Show the answer and mark scheme
(a)
add dilute (hydrochloric) acid to a sample of each solid
sodium chloride does not fizz / produces no gas (the carbonates fizz)
(b)
flame test
calcium carbonate gives an orange-red flame and sodium carbonate gives a yellow flame