1.3e use chemical equations to calculate reacting masses and vice versa using the concepts of amount of substance and molar mass AND 1.3f use chemical equations to calculate volumes of gases and vice versa using the concepts of amount of substance and molar volume of gases, eg calculation of the mass or volume of CO2 produced by combustion of a hydrocarbon (given a molar volume for the gas)

You should know how to calculate reacting masses using this equation. For example:
What mass of magnesium oxide would be produced from 16g of magnesium in the reaction between magnesium and oxygen?
The equation is 2Mg + O2 --> 2MgO
You know that you have 16g of magnesium, so you can use this to calculate the moles of magnesium.
Moles = mass/RAM = 16g/24 gmol-1 = 0.67 moles
Next, you find out the ratio:
Mg : MgO, 2 : 2, 1:1, therefore both have 0.67 moles.
Therefore, the mass of MgO can be calculated with moles x RAM
Mass = moles x RAM = 0.67 x (24+16) = 26.67g

With the same question, you should be able to calculate the volume of O2 required. 

You already know how many moles of Mg you have (0.67 moles).

However, the ratio is different as you are trying to work out volume of oxygen, not magnesium oxide. Therefore, the ratio of Mg : O is 2 : 1, so the amount of moles of oxygen is half of 0.67, 0.034.

1 mole of a gas is 24dm3, so to work out the volume of oxygen, you have to do 0.034 x 24dm3, which equals 0.804dm3.

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CALCULATIONS OF PRODUCTS/REACTANTS BASED ON EQUATIONS
1. What mass of barium sulphate would be produced from 10g of barium chloride in the following reaction?
BaCl2 + H2SO4 --> BaSO4 + 2HCl
- calculate moles of barium chloride
moles = mass/RFM = 10g/(137+71) = 0.048 moles
- ratio
BaCl2 : BaSO4, 1 : 1, so both have 0.048 moles
- calculate mass of barium sulphate
mass = moles x RFM = 0.048 x (137+32+64) = 11.2g

2. What mass of potassium chloride would be produced from 20g of potassium carbonate?

3. What masses of ethanol and ethanoic acid would need to react together to give 1g of ethyl ethanoate?

4. What mass of iron (III) oxide would need to be reduced to produce 100 tonnes of iron in a blast furnace?

5. What mass of silver nitrate as a solution in water would need to be added to 5g of sodium chloride to ensure complete precipitation of the chloride?
AgNO3(aq) + NaCl(aq) --> AgCl(s) + NaNO3(aq)
- calculate the moles of sodium chloride
moles = mass/RFM = 5g/(23+35) = 0.086 moles
- ratio
NaCl : AgNO3, 1:1, therefore they have the same amount of moles
- calculate the mass of silver nitrate
mass = moles x RFM = 0.086 x (108+14+48) = 14.62g

6. A solution of copper sulfate reacts with sodium hydroxide solution to produce a precipitate of copepr hydroxide according to the following equation:
CuSO4(aq) + 2NaOH(aq) --> Cu(OH)2(s) + Na2SO4(aq)
What mass of sodium hydroxide would be needed to convert 15.96g of copper sulfate to copper hydroxide and what mass of copper hydroxide would be produced?
- calculate the moles of copper sulphate
moles = mass/RFM = 15.96g/(64+32+64) = 0.093 moles
- ratio
CuSO4 : 2NaOH, 1:2, 0.093 : 0.186
- calculate the mass of sodium hydroxide
mass = moles x RFM = 0.186 x (23+16+1) = 7.44g


7. What volume of ammonia gas would be needed to produce 40g of ammonium nitrate in the following reaction?
NH3(g) + HNO3(aq) --> NH4NO3(aq)
- calculate moles of ammonium nitrate
moles = mass/RFM = 40g/(28+4+48) = 0.5 moles
- ratio
NH3 : NH4NO3, 1:1, 0.5 moles
- calculate volume
moles x 24dm3 = 0.5 x 24dm3 = 12dm3 or 12000cm3

8. In the reaction between calcium carbonate and nitric acid what mass of calcium nitrate and what volume of carbon dioxide would be produced from 33.3g of calcium carbonate?

9. What would be the total volume of gas produced by the action of heat on 33.12g of lead (II) nitrate?

10. Magnesium reacts with sulfuric acid to produce a solution of magnesium sulphate. If this is allowed to crystallize out the solid produced has the formula MgSO4.7H20. Write out the equation for this reaction and calculate the mass of magnesium sulphate heptahydrate that could be produced from 4g of magnesium.
Mg(s) + H2SO4(aq) --> MgSO4(aq) + H2(g)
Mg(s) + H2SO4(aq) + 7H20(l)--> MgSO4.7H2O(s) + H2(g)
- calculate the moles of magnesium
moles = mass/RFM = 4g/24 = 0.167 moles
- ratio
Mg : MgSO4.7H2O, 1:1, 0.167 moles for both
- calculate the mass of magnesium sulphate heptahydrate
mass = moles x RFM = 0.167 x (24+32+176+14) = 41.082g

11. Copper (II) oxide reacts with sulphuric acid to produce copper (II) sulphate. If this is allowed to crystallize the formula of the crystals is CuSO4.5H2O.
What mass of copper oxide would be needed to produce 100g of crystals?
CuO + H2SO4 + 4H2O --> CuSO4.5H2O
- calculate moles of crystals
moles = mass/RFM = 100g/(64+32+144+10) = 0.4 moles
- ratio
CuSO4.5H2O : CuO, 1:1, 0.4 moles
- calculate the mass of copper oxide
mass = moles x RFM = 0.4 x (64+16) = 32g

12. Sulphur dioxide can be removed from the waste gases of a power station by passing it through a slurry of calcium hydroxide. The equation for this reaction is:
SO2(g) + Ca(OH)2(aq) --> CaSO3(aq) + H2O(l)
What mass of calcium hydroxide would be be needed to deal with 1000dm3 of sulphur dioxide?

13. In a fermentation reaction, glucose is converted to alcohol and carbon dioxide according to the following equation:
C6H12O6 --> 2C2H5OH + 2CO2
What mass of alcohol and what volume of carbon dioxide would be produced from 10g of glucose?
- calculate moles of glucose
moles = mass/RFM = 10g/(72+12+96) = 0.056 moles
- ratio
C6H12O6 : 2C2H5OH, 1:2, 0.056:0.111
- calculate mass of alcohol
mass = moles x RFM = 0.111 x (24+6+16) = 5.106g
- ratio 
C6H12O6 : 2CO2, 1:2, 0.056:0.111
- calculate volume
volume = moles x 24dm3 = 0.111 x 24dm3 = 2.664dm3

14. In the following reactions calculate the mass of precipitate formed from 20g of the metal salt in each case.
i) ZnSO4 + 2NaOH --> Zn(OH)2 + Na2SO4
- calculate the moles of ZnSO4
moles = mass/RFM = 20g/(65+32+64) = 0.124 moles
-ratio
ZnSO4 : Zn(OH)2, 1:1, 0.124 moles
- calculate the mass of Zn(OH)2
mass = moles x RFM = 0.124 x (65+2+32) = 12.276g
ii) Al2(SO4)3 + 6NaOH --> 2Al(OH)3 + 3Na2SO4
- calculate the moles in Al2(SO4)3
moles = mass/RFM = 20g/(54+96+192) = 0.058 moles
- ratio
Al2(SO4)3 : 2Al(OH)3, 1:, 0.058 moles:0.117
- calculate the mass of 2Al(OH)3
mass = moles x RFM = 0.117 x (27+3+48) = 9.126g
iii) MgSO4 + 2NaOH --> Mg(OH)2 + Na2SO4
- calculate the moles of MgSO4
moles = mass/RFM = 20g/(24+32+64) = 0.167 moles
- ratio
MgSO4 : Mg(OH)2, 1:1, 0.167 moles
- calculate the mass of Mg(OH)2
mass = moles x RFM = 0.167 x (24+2+32) = 9.686g

15. What volume of hydrogen would be produced by 1g of calcium in its reaction with water?

16. What mass of magnesium would be needed to produce 100cm3 of hydrogen?

17. Chlorine reacts with sodium hydroxide as follows:
Cl2 + 6NaOH --> 5NaCl + NaClO3 + 3H2O
What mass of sodium chloride and what mass of sodium (V) chlorate would be produced from 240cm3 of chlorine gas?
- calculate moles of chlorine
moles x 24dm3 = volume of a gas, so moles = volume of a gas/24dm3
moles = volume of a gas/24dm3 = 2.4dm3/24dm3 = 0.1 moles
- ratio 
Cl2 : 5NaCl, 1:5, 0.1:0.5
- calculate mass of 5NaCl
mass = moles x RFM = 0.5 x (23+35) = 29g (the answer should be 2.9g, I think that this is a mistake a made when I was calculating the moles from the volume. Instead of calculating it all in cm3, I calculated it all in dm3)
- ratio
Cl2 : NaClO3, 1:1, 0.1 moles
- calculate the mass of NaClO3
mass = moles x RFM = 0.1 x (23+35+48) = 10.6g (again, this answer is almost right)

18. When nitrogen reacts with hydrogen in the Haber process only 17% of the nitrogen is converted to ammonia. What volume of nitrogen and what volume of hydrogen would be needed to produce 1 tonne of ammonia? (1 tonne = 1x106g)

19. Nitric acid is produced by the following series of reactions:
4NH3 + 5O2 --> 4NO + 3H2O
4NO + 02 --> 4NO2
4NO2 + O2 + 2H2O --> 4HNO3
What mass of nitric acid would be produced from 17 tonnes of ammonia and what volume of oxygen would be needed in the reaction?
- calculate the moles of ammonia
moles = mass/RFM = 17t/(14+3) = 1 mole
- ratio
4NH3 : 4HNO3, 4:4, 1:1, 1 mole
- calculate the mass of nitric acid
mass = moles x RFM = 1 x (1+14+48) = 720 tonnes (this is completely wrong, the answer should be 63 tonnes, but I'm not sure what went wrong)
- ratio
4NH3 : O2, 4:1, 1:0.25 moles
- calculate the volume of oxygen
volume = moles x 24dm3 = 0.25 x 24dm3 = 6dm3 (this is also extremely wrong)

20. Hardness in water is caused by dissolved calcium compounds. When heated, some of these break down and deposit calcium carbonate as follows:
Ca(HCO3)2 --> CaCO3 + H2O +CO2
This builds up as "fur" on the inside of boilers. It can be removed by reaction with hydrochloric acid.
What mass of calcium carbonate would be produced from 10,000dm3 of water containing 0.356g of calcium hydrogen carbonate per dm3 of water and what volume of 10 mol dm-3 hydrochloric acid solution would be needed to remove the solid calcium carbonate from the inside of the boiler?

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REACTIONS INVOLVING GASES
Assume that you have 10cm3 of the first named reactant and then calculate the volumes of all the gases involved in the equation. In these examples, the reactions are being carried out at above 100 degrees Celsius and you should assume the water is present as a gas and therefore has a volume.

1. CH4 + 2O2 --> CO2 + 2H2O
CH4: 10cm3 
O2: 20cm3 
CO2: 10cm3
H2O: 20cm3

2. C2H4 + 3O2 --> 2CO2 +2H2O
C2H4: 10cm3 
O2: 30cm3 
CO2: 20cm3 
H2O: 20cm3 

3. 2C2H2 +5O2 --> 4CO2 + 2H2O
C2H2: 10cm3 
O2: 25cm3 
CO2: 20cm3 
H2O: 10cm3 

4. 2C8H18 + 25O2 --> 16CO2 + 18H2O
C8H18: 10cm3 
O2: 125cm3 
CO2: 80cm3 
H2O: 90cm3 

5. N2 + 3H2 --> 2NH3
N2: 10cm3 
H2: 30cm3 
NH3: 20cm3