Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Reversing the calculations
20 practice questions
Practice questions
1–3 of 3 · Hard
Question 1
2 marks · Hard
Answer and see the solution →A student wants to completely neutralise 10.0 cm³ of 0.200 mol/dm³ nitric acid with sodium carbonate solution. The balanced equation for the reaction is:
Calculate the minimum volume, in cm³, of 0.100 mol/dm³ sodium carbonate solution required to react fully with the nitric acid.
Question 2
5 marks · Hard
Answer and see the solution →Calcium hydroxide solution reacts with hydrochloric acid according to the following balanced equation:
In a titration, 25.0 cm³ of hydrochloric acid solution of concentration 0.120 mol/dm³ is reacted completely with calcium hydroxide solution.
(a)[1 mark]Calculate the number of moles of HCl present in 25.0 cm³ of solution.
(b)[1 mark]Determine the number of moles of Ca(OH)₂ required to react with this amount of HCl.
(c)[2 marks]Given that the concentration of Ca(OH)₂ is 0.0800 mol/dm³, calculate the volume (in cm³) of Ca(OH)₂ solution that supplies this amount of Ca(OH)₂.
(d)[1 mark]Explain briefly why it is important to use the balanced equation when carrying out these calculations.
Question 3
2 marks · Hard
Answer and see the solution →A solution contains 0.00500 mol of a substance at a concentration of 0.250 mol/dm³.
Calculate the volume of this solution, in cm³, required to provide 0.00500 mol of the substance.