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
51–60 of 61 · Normal
Question 51
3 marks · Normal
Answer and see the solution →Potassium hydroxide solution reacts with sulfuric acid as follows:
Calculate the minimum volume (in cm³) of 0.150 mol/dm³ sulfuric acid required to completely react with 25.0 cm³ of 0.300 mol/dm³ potassium hydroxide solution.
Question 52
3 marks · Normal
Answer and see the solution →Explain, using a calculation, how you would work out the volume of 0.250 mol/dm³ potassium hydroxide solution needed to neutralise 10.0 cm³ of 0.500 mol/dm³ sulfuric acid, given the following equation:
Show your reasoning and working clearly.
Question 53
2 marks · Normal
Answer and see the solution →Ammonia reacts with hydrochloric acid according to the equation:
Calculate the required volume (in cm³) of 0.250 mol/dm³ ammonia solution needed to react completely with 15.0 cm³ of 0.200 mol/dm³ hydrochloric acid solution.
Question 54
4 marks · Normal
Answer and see the solution →A student has 0.00800 mol of citric acid dissolved in water to make a solution. She needs to prepare the solution so that its concentration is exactly 0.200 mol/dm³.
(a)[1 mark]Write the rearranged formula used to calculate the volume required in dm³, in terms of moles and concentration.
(b)[2 marks]Calculate the required volume of solution, in dm³, to make the desired concentration.
(c)[1 mark]Convert your answer from (b) to cm³.
Question 55
3 marks · Normal
Answer and see the solution →Explain, step by step, how you would calculate the required volume of one solution needed to react completely with a known amount of another reactant, using their concentrations and the chemical equation. Include the reason for each step.
Question 56
4 marks · Normal
Answer and see the solution →The table shows several solutions, each with a different number of moles and concentration.
Solution data Solution Moles (mol) Concentration (mol/dm³) A 0.00250 0.100 B 0.00800 0.200 C 0.00450 0.300 D 0.00180 0.0600 For each solution in the table, calculate and enter the volume (in cm³) needed to contain the given moles at the given concentration. Show your working for Solution A.
Question 57
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 58
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 59
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 60
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.