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
61–70 of 144
Question 61
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 62
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 63
1 mark · Easy
Answer and see the solution →Write the concentration, in words, for a solution described as 0.1 mol/dm³ sodium chloride.
Question 64
3 marks · Easy
Answer and see the solution →(a)A student wants to make 500 cm³ of a 0.08 mol/dm³ solution of calcium chloride (CaCl₂).
(i)[2 marks]Calculate the amount of CaCl₂ (in mol) needed.
(ii)[1 mark]State the volume, in dm³, of solution the student will prepare.
Question 65
2 marks · Easy
Answer and see the solution →A solution has a concentration of 0.25 mol/dm³. What volume of this solution (in cm³) contains 0.050 mol of solute? Show your answer to the nearest cm³.
Question 66
2 marks · Normal
Answer and see the solution →A solution contains 4.0 g of potassium chloride (KCl) dissolved in exactly 100 cm³ of water. Calculate the concentration of this solution in g/dm³.
Question 67
4 marks · Normal
Answer and see the solution →(a)[1 mark]Give the formula that links concentration in mol/dm³, amount in mol, and volume in dm³.
(b)[1 mark]A student dissolves 2.5 g of magnesium sulfate (MgSO₄, Ar: Mg = 24, S = 32, O = 16) in 200 cm³ of water.
i. Calculate the number of moles of MgSO₄ in the solution.
(c)[2 marks]ii. Calculate the concentration of MgSO₄ in mol/dm³ in the solution.
Question 68
3 marks · Normal
Answer and see the solution →Calculate the mass of sodium nitrate (NaNO₃, Ar: Na = 23, N = 14, O = 16) required to make 250 cm³ of a 0.050 mol/dm³ solution.
Question 69
3 marks · Normal
Answer and see the solution →A teacher claims that doubling the amount of solute added to a fixed volume of water will always double the concentration of the solution. Explain using calculations and an example whether this statement is correct.
Question 70
4 marks · Normal
Answer and see the solution →Concentration and volume data for sodium sulfate solutions Sample Concentration (mol/dm³) Volume used (dm³) A 0.10 0.020 B 0.20 0.015 C 0.40 0.025 (a)[2 marks]Which sample contains the largest amount of sodium sulfate? Show your calculations.
(b)[1 mark]State the amount in mol present in that sample.
(c)[1 mark]Suggest one reason why a higher concentration solution may have less sodium sulfate than a lower concentration solution.