1. The Mole 2 Calculations involving gases. Highly relevant – what volume of CO 2 is produced when 20 tonnes of fuel is burned?

2. 1 mole of any gas occupies the same volume (under the same conditions of temperature and pressure) The molar volume (vol of one mole) is 24.00 litres (shown as dm 3 ) Often you will see this given as molar volume = 24.00 dm 3 mol -1

3. How do we convert a number of moles into a volume? Hint – use an easy example if you forget E.g. if one mole occupies 24 dm 3 then 2 moles must occupy 48 dm 3 i.e. 2 x 24 Volume (dm 3 ) = moles x 24 dm 3 Rearrange Moles = volume(in dm 3 ) 24

4. Example question – calculate the volume of chlorine which will react with 10.0g of aluminium metal Step 1 – write the equation 2Al+3Cl 2  2AlCl 3 Step 2 – convert the mass given into a number of moles i.e. count how many aluminium atoms you have (unit of moles). 10g of Al =mass/molar mass = 10g/27g =0.370 moles of Al

5. Step 3 - Use the equation to allow you to count how many particles (unit of moles) of the required substance are involved 2Al+3Cl 2  2AlCl 3 0.370 moles of Al will react with how many moles of chlorine? 0.370 x 1.5 moles of Cl 2 = 0.555 moles Volume (dm 3 ) = moles x 24 dm 3 Volume of Cl 2 =0.555 x 24 = 13.32 dm 3

6. Step 4 - use the number of moles and the molar volume to work out the volume Volume (dm 3 ) = moles x 24 dm 3 Volume of Cl 2 =0.555 x 24 = 13.32 dm 3