1. 1.1.2 Moles and equations
This Powerpoint contains the questions and answers for the activities 1-20

2. 1. Convert the following masses as specified.
i)0.357 kg into g;
ii)5.46 tonnes into g;
iii) g into tonnes;
iv)1.34 x 109 g into kg;
v)1.43 x 10-7 tonnes into g.

3. 1. Convert the following masses as specified- Answers
i)0.357 kg into g; g
ii)5.46 tonnes into g; g
iii) g into tonnes; 89 tonnes
iv)1.34 x 109 g into kg; kg
v)1.43 x 10-7 tonnes into g g

4. 2. Conversion of volumes into different units
i)0.357 dm3 into cm3;
ii)6.35 m3 into cm3;
iii) cm3 into m3;
iv)7.48 x 10-7 m3 into cm3.

5. 2. Conversion of volumes into different units
i)0.357 dm3 into cm3; cm3
ii)6.35 m3 into cm3; cm3
iii) cm3 into m3; 51m3
iv)7.48 x 10-7 m3 into cm cm3

6. 3. Using significant figures
Answering to 3 significant figures
Write the following numbers to 3 significant figures i)
ii)
iii)
iv)
v) x 10-4

7. 3. Using significant figures
ii)
iii)
iv)
v) x x 10-4

8. 5. Categorizing materials as substances or mixtures
Underline the materials from the list below which you would describe as substances (Hint; substances are those which are not mixtures).
Sugar, water, air, seawater , wood, sodium chloride, sulphur dioxide, chlorine, calcium, lemon juice, bromine, plastic

9. 6. Converting numbers of particles into moles
Convert the following numbers of particles into moles
i)12.04 x 1023 electrons;
ii) 1.35 x 1024 sodium ions

10. 6. Converting numbers of particles into moles
i) x 1023 electrons; 2 moles
ii) 1.35 x 1024 sodium ions; moles

11. 7. Converting moles into numbers of particles
i) How many particles are present in moles of electrons?
ii) How many atoms are present in 2.4 moles of magnesium?

12. 7. Converting moles into numbers of particles
i) How many particles are present in moles of electrons? 1.93x1021
ii) How many atoms are present in 2.4 moles of magnesium? x1024

13. 9. Finding the molar masses of simple compounds
Calculate the molar mass of the following compounds from their formulae
i) CO2
ii) H2O
iii) Ca(OH)2
iv) NH4NO3

14. 9. Finding the molar masses of simple compounds
i) CO g
ii) H2O g
iii) Ca(OH) g
iv) NH4NO g

15. 10. Calculating the percentage by mass of an element in a compound
Calculate the percentage by mass of the named element in each of the compounds listed.
i) Aluminium in AlCl3
ii) Hydrogen in (NH4)3PO4

16. 10. Calculating the percentage by mass of an element in a compound
i) Aluminium in AlCl %
Mr 133.5
ii) Hydrogen in (NH4)3PO %
Mr 149.1

17. 12. Deducing the molecular formula from empirical formula and molar mass
i) An oxide of hydrogen with molar mass 34 has an empirical formula OH. What is the molecular formula?

18. 12. Deducing the molecular formula from empirical formula and molar mass
i) An oxide of hydrogen with molar mass 34 has an empirical formula OH. What is the molecular formula? H2O2

19. 13. Calculating the empirical formula from percentage composition
Work out the empirical formulae for the following compounds
i) N 87.5% H 12.5%

20. 13. Calculating the empirical formula from percentage composition
i) N 87.5% H 12.5% NH2

21. 14. Calculating the empirical formula from the percentage of one reactant
Work out the empirical formulae for the following compounds
i) A chloride of chromium which contains 73.3% chlorine;
ii) A chloride of copper which contains 47.2% copper.

22. 14. Calculating the empirical formula from the percentage of one reactant
i) A chloride of chromium which contains 73.3% chlorine; CrCl4
ii) A chloride of copper which contains 47.2% copper. CuCl2

23. 17. Writing symbol equations for reactions we have studied
Write symbol equations for the following.
i) magnesium + copper sulphate → copper + magnesium sulphate
ii) sodium hydrochloric → sodium + water + carbon carbonate acid chloride dioxide

24. 17. Writing symbol equations for reactions we have studied
i) magnesium + copper sulphate → copper + magnesium sulphate
Mg + CuSO4 → Cu + MgSO4
ii) sodium hydrochloric → sodium + water + carbon carbonate acid chloride dioxide
Na2CO HCl →2NaCl + H2O CO2

25. 18. Writing symbol equations for reactions with reactants or products stated
Write symbol equations for the following reactions.
i) Burning propane (C3H8) to produce carbon dioxide and water.
ii) The formation of calcium carbonate (CaCO3) from calcium oxide and carbon dioxide.
iii) Production of hydrogen sulphide (H2S) from its elements.
iv) Production of sulphur dioxide from its elements.
v) The reaction of silicon tetrachloride (SiCl4) with water to produce silicon dioxide and another product.

26. 18. Writing symbol equations for reactions with reactants or products stated
i) Burning propane (C3H8) to produce carbon dioxide and water.
C3H8 + 5O2 → 3CO2 + 4H2O
ii) d) The formation of calcium carbonate (CaCO3) from calcium oxide and carbon dioxide.
CaO + CO2 → CaCO3

27. (continued)
iii) Production of hydrogen sulphide (H2S) from its elements.
H2 + S → H2S
iv) Production of sulphur dioxide from its elements.
S + O2 → SO2
v) The reaction of silicon tetrachloride (SiCl4) with water to produce silicon dioxide and another product.
SiCl4 + 2H2O → SiO2 + 4HCl

28. 19. Reacting masses: using moles=mass/Mr
How many moles are in the following substances? (answer to 3 sf)
i) 1.6g of methane gas; ____
ii) 30.4g of sodium; ____
iii) 90.2g of aluminium sulphide; ____
iv) 1.7g of ammonium oxide; ____

29. 19. Reacting masses: using moles=mass/Mr
i) 1.60g of methane gas;
ii) 30.4g of sodium;
iii) 90.2g of aluminium sulphide;
iv) 1.7g of ammonium oxide;

30. 20. Calculating the mass from the number of moles
Work out the masses of the following quantities.
i) 5 moles of calcium
ii) 0.5 moles of water;
iii) 1.2 moles of magnesium chloride;
iv) 7.86 x 10-6 moles of hydrogen chloride.

31. 20. Calculating the mass from the number of moles
i) 5 moles of calcium g
ii) 0.5 moles of water; g
iii) 1.2 moles of magnesium chloride; g
iv) 7.86 x 10-6 moles of hydrogen chloride g

32. 21.
i) How many moles of iron will react with chlorine to form 0.47 mole of iron (III) chloride?
2Fe(s) Cl2(g) → 2FeCl3(s)

33. Answers
i) How many moles of iron will react with chlorine to form 0.47 mole of iron (III) chloride? 0.47
2Fe(s) Cl2(g) → 2FeCl3(s)

34. 21.
ii) How many moles of calcium chloride could you obtain by action of excess acid on 5.43 moles of calcium carbonate?
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)
iii) How many moles of sodium chloride can be produced by reacting 0.5 moles of chlorine?
2Na(s) + Cl2(g) → 2NaCl(s)

35. Answers
ii) How many moles of calcium chloride could you obtain by action of excess acid on 5.43 moles of calcium carbonate? 5.43
CaCO3(s)+ 2HCl(aq)→CaCl2(aq)+ CO2(g)+ H2O(l)
iii) How many moles of sodium chloride can be produced by reacting 0.5 moles of chlorine? 1
2Na(s) + Cl2(g) → 2NaCl(s)

36. 21.
iv)How many moles of sodium carbonate can be obtained by heating 0.5 moles of sodium hydrogen carbonate?
2NaHCO3 (s) → Na2CO3 + CO2(g) + H2O(l)
v) How many moles of sodium carbonate can be obtained by heating 1.3 moles of sodium hydrogen carbonate?
vi) How many moles of calcium phosphate are needed to produce moles of P4 by the reaction below (answer to 3 sf)?
2Ca3(PO4)2 + 6SiO2 + 5C → P4 + 6CaSiO3 +5CO2

37. Answers
iv) How many moles of sodium carbonate can be obtained by heating 0.5 moles of sodium hydrogen carbonate? 0.25
v) How many moles of sodium carbonate can be obtained by heating 1.3 moles of sodium hydrogen carbonate? 0.65
2NaHCO3 (s) → Na2CO3 + CO2(g) + H2O(l)
vi) How many moles of calcium phosphate are needed to produce moles of P4 by the reaction below? 0.652
2Ca3(PO4)2+ 6SiO2 + 5C→ P4 + 6CaSiO3 +5CO2

38. 21.
vii)How many moles of aluminium chloride can be made from 1 mole of chlorine (answer to 3 sf)?
2Al(s) Cl2(g) → 2AlCl3(s)
viii) How many moles of aluminium chloride can be made from 0.72 moles of chlorine (answer to 3 sf)?

39. 21. ANSWERS
vii)How many moles of aluminium chloride can be made from 1 mole of chlorine (answer to 3 sf)? 0.67
2Al(s) Cl2(g) → 2AlCl3(s)
viii) How many moles of aluminium chloride can be made from 0.72 moles of chlorine (answer to 3 sf)? 0.48

40. 22.
i) Calculate the mass of lead (II) nitrate needed to produce 22.3g of lead (II) oxide in the reaction shown below.
2Pb(NO3)2 (s) → 2PbO (s) + 4NO2(g) + O2(g)

41. 22. Answers
i) Calculate the mass of lead (II) nitrate needed to produce 22.3g of lead (II) oxide in the reaction shown below g
2Pb(NO3)2 (s) → 2PbO (s) + 4NO2(g) + O2(g)

42. 22.
ii) Calculate the mass of calcium chloride you could obtain by action of excess acid on 15g of calcium carbonate.
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l) )
iii) Calculate the mass of iron oxide made from 14g of iron.
3Fe(s) O2(g) → Fe3O4(s)

43. 22. Answers
ii) Calculate the mass of calcium chloride you could obtain by action of excess acid on 15g of calcium carbonate g
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)
iii) Calculate the mass of iron oxide made from 14g of iron. 19.3g
3Fe(s) O2(g) → Fe3O4(s)

44. 22.
iv) Find the maximum mass of sodium carbonate which can be obtained by heating 100g of sodium hydrogen carbonate.
2NaHCO3 (s) → Na2CO3+ CO2(g) + H2O(l)

45. 22. Answers
iv) Find the maximum mass of sodium carbonate which can be obtained by heating 100g of sodium hydrogen carbonate. 63.1g
2NaHCO3 (s) → Na2CO3 + CO2(g) + H2O(l)

46. 23. Calculating the number of moles from gas volume
i) cm3 of methane;
ii) 4000 cm3 of nitrogen;
iii) 18dm3 of fluorine;
iv) cm3 of helium;

47. Answers i) 48000 cm3 of methane; 2 moles
ii) 4000 cm3 of nitrogen; moles
iii) 18dm3 of fluorine; 0.75 moles
iv) cm3 of helium; 1.35 x 10-5moles

48. 24. i) 3 moles of methane; ii) 1.4 moles of hydrogen;
iii) 7.6g of fluorine;
iv) 13 tonnes of ethane.

49. Answers i) 3 moles of methane; 72dm3
ii) 1.4 moles of hydrogen; 33.6dm3
iii) 7.6g of fluorine; 4.8dm3
iv) 13 tonnes of ethane x 107 dm3

50. Activity 25a Calculating the mass or volume of a product from the mass or volume of a reactant
i) What volume of ethyne (C2H2) can be produced from 10g of calcium carbide by the following reaction?
CaC2(s) + 2H2O(l)→ Ca(OH)2(aq) + C2H2(g)

51. 2KClO3(s)) → 2KCl(s) + 3O2(g)
Activity 25a Continued Calculating the mass or volume of a product from the mass or volume of a reactant
ii) What mass of PbO2 is required to produce 40dm3 of oxygen by the equation shown below?
2PbO2(s)) → 2PbO(s) + O2(g)
iii) What mass of potassium chlorate (v) must be heated to give 1.00dm3 of oxygen in the following reaction?
2KClO3(s)) → 2KCl(s) + 3O2(g)

52. iv) What volume of chlorine is produced from 340g of Pb3O4?
Activity 25a Continued Calculating the mass or volume of a product from the mass or volume of a reactant
iv) What volume of chlorine is produced from 340g of Pb3O4?
Pb3O4 (s) + 8HCl(l) → 3PbCl2(s)+Cl2(g)+ 4H2O(l)

53. Activity 25a Continued Calculating the mass or volume of a product from the mass or volume of a reactant
v) Calculate the volume of carbon dioxide produced when 5g of calcium carbonate is treated with excess hydrochloric acid.

54. Activity 25a ANSWERS i) 3.74dm3 (3740cm3) ii) 3.41g iii) 11.9dm3
iv) 1.2 dm3 (1200cm3)

55. Activity 26 Calculate the number of moles of dissolved substance in the following quantities of solutions
i) 500cm3 of 1moldm-3 NaOH; ii) 31.55cm3 of 0.01moldm-3 HCl; iii) 28.40cm3 of 0.02moldm-3 NaOH.

56. Exercise 26: Answers i) 0.5 moles ii) 0.000316 moles (3.16x10-4)
iii) moles (5.68x10-4)

57. Activity 27 Calculating the concentration from number of moles of dissolved substance and solution volume
i) 0.2 moles of NaOH in 1000cm3 of solution; ii) 0.2 moles of NaOH in 52cm3 of solution; iii) moles of HCl in 32.55cm3 of solution;

58. Exercise 27: Answers i) 0.2 mol dm-3 ii) 3.85 mol dm-3
iii) 4.21 mol dm-3

59. Activity 28 Calculating the solution volume from number of moles of dissolved substance and concentration
i) 0.43 moles of HCl; the concentration of HCl is 1moldm-3; ii) 5.1 moles of NaOH; the concentration of NaOH is 1moldm-3; iii) moles of HCl; the concentration of HCl is 0.02moldm-3;

60. Exercise 28: Answers
i) 430 cm3
ii) 5100 cm3
iii) 1605 cm3

61. Activity 29 Calculating the concentration of a reactant from the concentration and volume of the other reactant
i) In a titration to calculate the concentration of some sodium hydroxide solution, a student took 20cm3 of the sodium hydroxide and used 15 cm3 of hydrochloric acid of concentration 0.50 moldm-3 to neutralise it. Calculate the concentration of the sodium hydroxide. NaOH(aq)+ HCl(aq) → NaCl(aq) + H2O(l)

62. Activity 29
ii) If 25.0cm3 of a solution of sodium hydroxide are neutralised by 27.5 cm3 of sulphuric acid of concentration moldm-3, what is the concentration of the sodium hydroxide?
2NaOH(aq)+ H2SO4(aq) →Na2SO4 (aq) + 2H2O(l)

63. Exercise 29: Answers
i) mol dm-3
ii) 0.55 mol dm-3

64. Activity 30. Calculating reacting volumes, given the reaction equation and n=cv/1000 data
i) Predict the volume of hydrochloric acid (0.2moldm-3) needed to neutralise 250cm3 0.2moldm-3 sodium carbonate. Na2CO3 (aq) + 2HCl(aq) → 2NaCl(aq) + CO2(g) + H2O(l)

65. Activity 30. Calculating reacting volumes, given the reaction equation and n=cv/1000 data
ii) Predict the volume of phosphoric acid (0.1moldm-3) needed to neutralise 30cm3 0.1moldm-3 sodium hydroxide. 3NaOH(aq) + H3PO4(aq) →Na3PO4 (aq) + 3H2O(l)

66. Activity 30. Calculating reacting volumes, given the reaction equation and n=cv/1000 data
iii) Predict the volume of sulphuric acid (0.1moldm-3) needed to neutralise 21.25cm3 0.25moldm-3 sodium hydroxide. 2NaOH(aq) + H2SO4(aq) →Na2SO4 (aq) + 2H2O(l)

67. Exercise 30: Answers
i) 500 cm3
ii) 10 cm3
iii)26.6 cm3

68. 32. Deducing the stoichiometric relationship from given masses and gas volumes
i) When heated, 0.080g of sulphur reacted with 60cm3 oxygen to produce an oxide of sulphur. Deduce the formula of the oxide.

69. Exercise 32: Answers
SO2