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
21–30 of 59 · Easy
Question 21
3 marks · Easy
Answer and see the solution →The table shows the volume of a gas produced from the reaction of different masses of magnesium with excess hydrochloric acid at room temperature and pressure.
Mass of magnesium (g) Volume of H₂ gas (dm³) 0.12 0.12 0.24 0.24 0.36 0.36 (a)[1 mark]Describe the relationship between the mass of magnesium and the volume of hydrogen gas produced.
(b)[1 mark]Suggest the volume of hydrogen gas (in dm³) produced from 0.48 g of magnesium.
(c)[1 mark]Explain your answer to part (b).
Question 22
1 mark · Easy
Answer and see the solution →Write the formula relating number of moles, volume of gas (in dm³), and molar volume at room temperature and pressure.
Question 23
3 marks · Easy
Answer and see the solution →(a)Potassium reacts with water to produce potassium hydroxide and hydrogen gas according to:
If 4.6 g of potassium (Ar: K = 39) reacts completely, calculate:
(i)[1 mark]the number of moles of potassium reacted.
(ii)[1 mark]the number of moles of hydrogen gas formed.
(iii)[1 mark]the volume of hydrogen gas produced at rtp (in dm³).
Question 24
2 marks · Easy
Answer and see the solution →Calculate the volume in cm³ of 0.015 mol of nitrogen gas at room temperature and pressure.
Question 25
1 mark · Easy
Answer and see the solution →State the units used for concentration when it is measured in moles per cubic decimetre.
Question 26
3 marks · Easy
Answer and see the solution →(a)[1 mark]Give the formula that links concentration (in mol/dm³), amount of substance (in mol), and volume of solution (in dm³).
(b)A student dissolves 0.080 mol of potassium nitrate (KNO₃) in enough water to make 0.40 dm³ of solution.
(i)[2 marks]Calculate the concentration of this potassium nitrate solution in mol/dm³.
Question 27
2 marks · Easy
Answer and see the solution →Calculate the amount of substance (in mol) in 200 cm³ of a solution with a concentration of 0.150 mol/dm³. Give your answer to 2 decimal places.
Question 28
2 marks · Easy
Answer and see the solution →A student claims that halving the volume of a solution, while keeping the amount of solute the same, will double its concentration. Explain why the student is correct. Use calculations in your answer.
Question 29
3 marks · Easy
Answer and see the solution →The following table shows the amounts and volumes for three different solutions of lead(II) nitrate.
Sample Amount (mol) Volume (dm³) A 0.10 0.50 B 0.20 0.80 C 0.04 0.20 (a)[1 mark]Calculate the concentration, in mol/dm³, for sample A.
(b)[1 mark]Calculate the concentration for sample B.
(c)[1 mark]Which sample has the highest concentration?
Question 30
1 mark · Easy
Answer and see the solution →Write the concentration, in words, for a solution described as 0.1 mol/dm³ sodium chloride.