Making Solutions of Known Concentration
You will make 2 solutions of Sodium Chloride and water and 2 solutions of Copper
Sulphate and water – they will be of different concentrations. You will then work out the
concentration of these solutions in g/cm3 and mol/dm3.
Method
1. Make a solution of 5.8g of Sodium Chloride in 100cm3 of water.
2. Make another solution of 10.16g of sodium chloride in 50cm3 of water.
3. Make a solution of 4g of copper sulphate in 100cm3 of water.
4. Make another solution of 2g of copper sulphate in 50cm3 of water.
Analysis
1. How many moles of Sodium Chloride (NaCl) or Copper Sulphate are in each
solution?
(Remember that: number of moles = mass  mass of 1 mole)
2. If you took 1cm3 of solution out of each beaker, how many moles would you
have in that 1cm3 of it? (Remember you have started with either 100cm3 or
50cm3 of solution.)
This is how many moles you have per cm3.
3. To get your concentration in moles per dm3, you have to multiply your answer to
(2) by 1000 as 1dm3 = 1000cm3.
Write down the concentration of your solutions in moles/ dm 3.
4. Now work out your concentration in g/ dm3:
Mass = no of moles x mass of 1 mole