Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Chemical Formulae, Equations and Calculations Part 2
144 practice questions
Topics covered
- Calculations involving gas volumes19 practice questions
- Calculating the volume of a certain number of moles19 practice questions
- Using the molar volume in calculations with chemical equations19 practice questions
- Concentrations of solutions19 practice questions
- Calculations with equations involving solutions19 practice questions
- The standard calculation19 practice questions
- Reversing the calculations20 practice questions
Practice questions
131–140 of 144
Question 131
3 marks · Normal
Answer and see the solution →Citric acid reacts with sodium hydroxide as follows:
Calculate the volume, in cm³, of 0.300 mol/dm³ sodium hydroxide solution required to completely neutralise 20.0 cm³ of 0.200 mol/dm³ citric acid solution.
Question 132
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 133
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 134
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.
Question 135
5 marks · Easy
Answer and see the solution →Ammonia gas is produced by the reaction of hydrogen gas with nitrogen gas at room temperature and pressure (rtp).
(a)[1 mark]State the balanced chemical equation for the formation of ammonia from hydrogen and nitrogen.
(b)[1 mark]What is the volume of 2 moles of hydrogen gas at rtp? Give your answer in dm³.
(c)[1 mark]Convert your answer to part (b) into cm³.
(d)[1 mark]If 1 mole of nitrogen gas reacts completely, how many moles of hydrogen gas are needed?
(e)[1 mark]Calculate the total volume (in dm³) of all gases present after the complete reaction of 1 dm³ nitrogen gas with excess hydrogen gas at rtp. (State your assumptions about volumes in your answer.)
Question 136
5 marks · Easy
Answer and see the solution →A student investigates the reaction between barium hydroxide and sulfuric acid:
(a)[2 marks]Calculate the number of moles of barium hydroxide in 40.0 cm³ of 0.200 mol/dm³ barium hydroxide solution.
(b)[3 marks]During a titration, 25.0 cm³ of the barium hydroxide solution from part (a) is neutralised by 19.5 cm³ of sulfuric acid solution.
Calculate the concentration of the sulfuric acid in mol/dm³. Show your working.
Question 137
5 marks · Easy
Answer and see the solution →Zinc sulfate solution reacts with barium chloride solution: \[ \ce{ZnSO4(aq) + BaCl2(aq) -> BaSO4(s) + ZnCl2(aq)} \] A titration is carried out to determine the amount of barium chloride solution required to completely react with a given volume of zinc sulfate solution.
(a)[1 mark]Write the mole ratio of zinc sulfate to barium chloride in the balanced chemical equation.
(b)[1 mark]In a titration, 30.0 cm³ of 0.150 mol/dm³ zinc sulfate solution reacts exactly with 30.0 cm³ of barium chloride solution. Calculate the number of moles of zinc sulfate used.
(c)[1 mark]Using your answers from (a) and (b), calculate the number of moles of barium chloride that react.
(d)[2 marks]Calculate the concentration (in mol/dm³) of the barium chloride solution.
Question 138
6 marks · Normal
Answer and see the solution →Potassium carbonate ( ) reacts with dilute hydrochloric acid:
(a)[2 marks]A student adds 0.20 g of solid potassium carbonate to 25.0 cma3 of dilute hydrochloric acid (an excess is present). Calculate the number of moles of potassium carbonate used. (Ar: K = 39, C = 12, O = 16)
(b)[2 marks]Calculate the maximum volume (in cma3) of carbon dioxide gas produced at room temperature and pressure. (Molar volume = 24,000 cma3 at rtp.)
(c)[2 marks]After the reaction, the solution is made up to 100.0 cma3 in a volumetric flask. Calculate the concentration, in mol/dma3, of potassium chloride present in the final solution.
Question 139
6 marks · Normal
Answer and see the solution →Citric acid reacts with sodium bicarbonate according to the following equation:
(a)[2 marks]A student reacts 0.420 g of sodium bicarbonate () with excess citric acid. Calculate the number of moles of sodium bicarbonate used. (Ar: Na = 23, H = 1, C = 12, O = 16)
(b)[2 marks]Calculate the volume, in dma3, of carbon dioxide gas produced at room temperature and pressure. (Molar volume = 24 dma3 at rtp.)
(c)[2 marks]The carbon dioxide produced is collected and completely dissolved in 250 cma3 of distilled water. Calculate the concentration of carbon dioxide (in mol/dma3) in this solution.
Question 140
6 marks · Normal
Answer and see the solution →A student reacts excess magnesium ribbon with 100 cm³ of 2.0 mol/dm³ hydrochloric acid in a flask at room temperature and pressure (rtp). Magnesium reacts with hydrochloric acid as follows:
(a)[2 marks]Calculate the amount, in moles, of hydrochloric acid present in 100 cm³ of 2.0 mol/dm³ HCl.
(b)[3 marks]Calculate the maximum volume, in cm³, of hydrogen gas produced at rtp.
(c)[1 mark]Suggest one reason why the actual volume of hydrogen collected might be less than this calculated value.