1. STANDARD GRADE CHEMISTRY CALCULATIONS Titrations V x C x P(acid) =V x C X P(alkali) Where V is the volume. C is the concentration P is the ‘Power’ of the acid or alkali. Worked example 1. Calculate the volume of 0.25 mol/l sodium hydroxide needed to neutralise 20 cm 3 of 0.1 mol/l sulphuric acid. V x C x P(acid) = V x C X P(alkali) 20 x 0.1 x 2 = V x 0.25 X 1 4 = V x 0.25 4 / 0.25 = V 16 cm 3 =V H 2 SO 4 so P = 2 NaOH so P = 1

2. Calculations for you to try. 1. Calculate the concentration of potassium hydroxide (KOH ) if 14.8 cm 3 is required to neutralise 20cm 3 of 0.1 mol/l nitric acid (HNO 3 ). Standard Grade Chemistry V x C x P(acid) = V x C X P(alkali) 20 x 0.1 x 1 = 14.8 x C X 1 2 = 14.8 x C 2 / 14.8 = C 0.135 mol/l = C

3. Calculations for you to try. 2. Calculate the volume of 0.15 mol/l sulphuric acid(H 2 SO 4 ) if it is neutralised by 25 cm 3 of 0.25mol/l sodium hydroxide (NaOH). Standard Grade Chemistry V x C x P(acid) = V x C X P(alkali) V x 0.15 x 2 = 25 x 0.25 X 1 V x 0.30 = 6.25 V = 6.25 / 0.30 = 20.83 cm 3