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

1. Convert the following masses as specified. i)0.357 kg into g; ii)5.46 tonnes into g; iii)89000000 g into tonnes; iv)1.34 x 109 g into kg; v)1.43 x 10-7 tonnes into g.

1. Convert the following masses as specified- Answers i)0.357 kg into g; 357g ii)5.46 tonnes into g; 5 460 000g iii)89000000 g into tonnes; 89 tonnes iv)1.34 x 109 g into kg; 1340000kg v)1.43 x 10-7 tonnes into g. 0.143g

2. Conversion of volumes into different units i)0.357 dm3 into cm3; ii)6.35 m3 into cm3; iii)51000000 cm3 into m3; iv)7.48 x 10-7 m3 into cm3.

2. Conversion of volumes into different units i)0.357 dm3 into cm3; 357cm3 ii)6.35 m3 into cm3; 6350000cm3 iii)51000000 cm3 into m3; 51m3 iv)7.48 x 10-7 m3 into cm3. 0.748cm3

3. Using significant figures Answering to 3 significant figures Write the following numbers to 3 significant figures i) 0.10752 ii) 58.942 iii) 0.0001178 iv) 23467889 v) 4.522 x 10-4

3. Using significant figures ii) 58.942 58.9 iii) 0.0001178 0.000118 iv) 23467889 23500000 v) 4.522 x 10-4 4.52 x 10-4

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

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

6. Converting numbers of particles into moles i) 12.04 x 1023 electrons; 2 moles ii) 1.35 x 1024 sodium ions; 2.2 moles

7. Converting moles into numbers of particles i) How many particles are present in 0.0032 moles of electrons? ii) How many atoms are present in 2.4 moles of magnesium?

7. Converting moles into numbers of particles i) How many particles are present in 0.0032 moles of electrons? 1.93x1021 ii) How many atoms are present in 2.4 moles of magnesium? 1.44 x1024

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

9. Finding the molar masses of simple compounds i) CO2 44g ii) H2O 18g iii) Ca(OH)2 74.1g iv) NH4NO3 80g

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

10. Calculating the percentage by mass of an element in a compound i) Aluminium in AlCl3 20.2% Mr 133.5 ii) Hydrogen in (NH4)3PO4 8.05% Mr 149.1

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?

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

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

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

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.

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

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

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 Na2CO3 + 2HCl →2NaCl + H2O + CO2

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.

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

(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

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; ____

19. Reacting masses: using moles=mass/Mr i) 1.60g of methane gas; 0.100 ii) 30.4g of sodium; 1.32 iii) 90.2g of aluminium sulphide; 0.600 iv) 1.7g of ammonium oxide; 0.0327

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.

20. Calculating the mass from the number of moles i) 5 moles of calcium 200.5g ii) 0.5 moles of water; 9.0g iii) 1.2 moles of magnesium chloride; 114.36g iv) 7.86 x 10-6 moles of hydrogen chloride. 0.000287g

21. i) How many moles of iron will react with chlorine to form 0.47 mole of iron (III) chloride? 2Fe(s) + 3Cl2(g) → 2FeCl3(s)

Answers i) How many moles of iron will react with chlorine to form 0.47 mole of iron (III) chloride? 0.47 2Fe(s) + 3Cl2(g) → 2FeCl3(s)

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)

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)

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 0.326 moles of P4 by the reaction below (answer to 3 sf)? 2Ca3(PO4)2 + 6SiO2 + 5C → P4 + 6CaSiO3 +5CO2

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 0.326 moles of P4 by the reaction below? 0.652 2Ca3(PO4)2+ 6SiO2 + 5C→ P4 + 6CaSiO3 +5CO2

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

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) + 3Cl2(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

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)

22. Answers i) Calculate the mass of lead (II) nitrate needed to produce 22.3g of lead (II) oxide in the reaction shown below. 33.12g 2Pb(NO3)2 (s) → 2PbO (s) + 4NO2(g) + O2(g)

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) + 2O2(g) → Fe3O4(s)

22. Answers ii) Calculate the mass of calcium chloride you could obtain by action of excess acid on 15g of calcium carbonate. 16.64g 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) + 2O2(g) → Fe3O4(s)

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)

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)

23. Calculating the number of moles from gas volume i) 48000 cm3 of methane; ii) 4000 cm3 of nitrogen; iii) 18dm3 of fluorine; iv) 0.325 cm3 of helium;

Answers i) 48000 cm3 of methane; 2 moles ii) 4000 cm3 of nitrogen; 0.167 moles iii) 18dm3 of fluorine; 0.75 moles iv) 0.325 cm3 of helium; 1.35 x 10-5moles

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

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. 1.04 x 107 dm3

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)

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)

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)

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.

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

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.

Exercise 26: Answers i) 0.5 moles ii) 0.000316 moles (3.16x10-4) iii) 0.000568 moles (5.68x10-4)

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) 0.137 moles of HCl in 32.55cm3 of solution;

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

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) 0.0321 moles of HCl; the concentration of HCl is 0.02moldm-3;

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

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)

Activity 29 ii) If 25.0cm3 of a solution of sodium hydroxide are neutralised by 27.5 cm3 of sulphuric acid of concentration 0.250 moldm-3, what is the concentration of the sodium hydroxide? 2NaOH(aq)+ H2SO4(aq) →Na2SO4 (aq) + 2H2O(l)

Exercise 29: Answers i) 0.374 mol dm-3 ii) 0.55 mol dm-3

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)

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)

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)

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

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.  

Exercise 32: Answers SO2