5.34 - Calculations from titrations

Question 1

How do you calculate your mean titre?

Answer 1

By taking all of your concordant titres, adding them, and dividing by the number of concordant titres

Question 2

How do you calculate the unknown concentration?

Answer 2

• Calculate the number of moles of the known substance
• Use the ratio to calculate the number of moles of the other substance
• Calculate the mass of the substance

Question 3

Volume of sodium carbonate solution used = 25cm3
Volume of nitric acid solution used = 27.25cm3
Concentration of sodium carbonate solution = 0.108 mol dm-3

What is the concentration of the nitric acid?

Answer 3

Number of moles of sodium carbonate = 0.108 * (25/1000) = 0.0027 moles

Ratio = 1:2, so moles of nitric acid = 0.0054 moles

Concentration of nitric acid = 0.0054/(27.25/1000) = 0.198 mol dm-3