Quick answer: A formula shows the ratio of atoms or ions in a substance, and for ionic compounds the charges must cancel. This Chemistry 9-10 test on balancing equations has 8 questions worth 20 marks, to do in 45 minutes: write formulae, balance the equations and state symbols. The mark scheme is on a separate page; free printable PDF.
This test lasts 45 minutes and carries 20 marks. Write every formula with correct capital letters, subscripts and brackets, and add state symbols where the question asks. Show how you checked each calculation, since credit is given for working.
Level: Chemistry grades 9-10 (GCSE · IGCSE · O Level · Class 9-10) · Curriculum: HS-PS1-7
Question 1 Write formulae (3 marks)
Write the formula of each compound.- Magnesium chloride (1 mark)
- Sodium sulfate (1 mark)
- Aluminium hydroxide (1 mark)
Question 2 Balance the equations (3 marks)
Balance each equation.- N₂ + H₂ → NH₃ (1 mark)
- Al + Cl₂ → AlCl₃ (1 mark)
- KClO₃ → KCl + O₂ (1 mark)
Question 3 State symbols (2 marks)
State the meaning of (aq), and give the state symbol for a gas. (2 marks)Question 4 Precipitate of silver bromide (3 marks)
Silver nitrate solution reacts with sodium bromide solution to form solid silver bromide and sodium nitrate solution.- Write the balanced equation with state symbols. (1 mark)
- Name the spectator ions. (1 mark)
- Write the ionic equation. (1 mark)
Question 5 Changing a subscript (2 marks)
A student balances Mg + O₂ → MgO by writing MgO₂ on the right. Explain why this is wrong and write the correct equation. (2 marks)Question 6 Burning aluminium (3 marks)
Aluminium burns in oxygen to form aluminium oxide. A mass of 5.4 g of aluminium forms 10.2 g of aluminium oxide.- Calculate the mass of oxygen that combined. (2 marks)
- Name the law that you used. (1 mark)
Question 7 Formula from ion cards (2 marks)
The ion cards show an iron(III) ion and a sulfate ion.Question 8 Charge on zinc (2 marks)
Zinc nitrate has the formula Zn(NO₃)₂. Deduce the charge on the zinc ion. (2 marks)
