900 cm³ of distilled water was added to 100cm³ of 0.5m sodium carbonate solution. calculate the concentration of the resulting solution in : -
(i) moles per litre.
(ii) grams per litre

(i) 0.05 mol/L; (ii) 5 g/L

Explanation:

We can use the dilution formula:

c1V1 = c2V2

Data:

c1 = 0.5 mol/L; V1 = 100 cm3

Added water = 900 cm3

Calculations:

(i) Moles per litre

V2 = 100 + 900 = 1000 cm^3 = 1 L

0.5 × 100 = c2 × 1000

          50 = c2 × 1000

          c2 = 0.05 mol/L

(ii) Grams per litre

c2 = 0.05 mol/L × (105.99 g/1 mol) = 5 g/L