Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Making soluble salts (except sodium, potassium and ammonium salts)
19 practice questions
Practice questions
11–19 of 19
Question 11
3 marks · Normal
Answer and see the solution →Write a balanced chemical equation for the reaction between magnesium carbonate and dilute sulfuric acid to form magnesium sulfate. State the products and their physical states.
Question 12
3 marks · Normal
Answer and see the solution →A student tries to make a pure sample of hydrated magnesium sulfate crystals using magnesium and dilute sulfuric acid.
Explain, in steps, what the student must do to obtain pure crystals and why each step is necessary.
Question 13
4 marks · Normal
Answer and see the solution →A student attempts to make hydrated nickel(II) sulfate crystals. Step Observation Add nickel(II) oxide to warm dilute sulfuric acid Black solid gradually disappears More nickel(II) oxide added Some solid remains at the bottom Filter the mixture Green solution collected Heat solution until some water evaporates Residue remains green Cool the solution Green crystals form (a)[1 mark]Explain why nickel(II) oxide is added in excess (step 2).
(b)[1 mark]Describe the purpose of step 3 (filtration).
(c)[1 mark]Explain why the solution is cooled after heating (step 5).
(d)[1 mark]Suggest a reason why it would be incorrect to heat the green solution to dryness in step 4.
Question 14
1 mark · Normal
Answer and check →Which of the following is the correct balanced equation for the reaction of copper(II) oxide with dilute sulfuric acid to make copper(II) sulfate?
- A.\ce{CuO(s) + H2SO4(aq) -> CuSO4(aq) + H2O(l)}
- B.\ce{CuO(aq) + H2SO4(s) -> CuSO4(l) + H2O(aq)}
- C.\ce{CuSO4(s) + H2SO4(aq) -> CuO(aq) + H2O(l)}
- D.\ce{Cu(s) + H2SO4(aq) -> CuSO4(aq) + H2(g)}
Question 15
2 marks · Normal
Answer and see the solution →Give two safety precautions you would take when preparing hydrated iron(II) sulfate crystals using dilute sulfuric acid and iron(II) oxide.
Question 16
4 marks · Normal
Answer and see the solution →(a)[1 mark]Define the term 'hydrated salt'.
(b)[2 marks]Explain, with reference to water of crystallisation, how heating a hydrated salt to dryness changes its formula.
(c)[1 mark]How can you tell if a sample of copper(II) sulfate is hydrated or anhydrous? State what you would observe on heating.
Question 17
2 marks · Hard
Answer and see the solution →When making hydrated zinc sulfate crystals from zinc oxide and sulfuric acid, the final solution is left to cool so that crystals form. Explain, in two points, why crystallisation is used instead of evaporation to dryness to obtain hydrated salt crystals.
Question 18
5 marks · Hard
Answer and see the solution →A student prepares hydrated magnesium sulfate crystals by reacting magnesium carbonate with dilute sulfuric acid.
(a)[2 marks]Write the balanced symbol equation for the reaction between magnesium carbonate and dilute sulfuric acid.
(b)[1 mark]State the state symbols for each product.
(c)[2 marks]During the process, the solution is concentrated and then left to crystallise. Write the equation for the crystallisation step, including water of crystallisation.
Question 19
2 marks · Hard
Answer and see the solution →Describe two steps a student must carry out to obtain pure hydrated copper(II) sulfate crystals from a mixture of copper(II) oxide and dilute sulfuric acid, once the reaction has finished.