Question

Calculate the formula unit masses of ZnO, Na2O, K2C03, given atomic masses of Zn = 65 u, Na = 23 u, K = 39 u, C = 12 u, and O = 16 u.

Answer 1

The formula unit mass of

(i) ZnO = 65 u + 16 u = 81 u

(ii) Na2O = (23 u x 2) + 16 u = 46 u + 16 u = 62 u

(iii) K2C03 = (39 u x 2) + 12 u + 16 u x 3

= 78 u + 12 u + 48 u = 138 u

Answer 2

The formula unit mass of

(i) ZnO = 65 u + 16 u = 81 u

(ii) Na2O = (23 u x 2) + 16 u = 46 u + 16 u = 62 u

(iii) K2C03 = (39 u x 2) + 12 u + 16 u x 3

= 78 u + 12 u + 48 u = 138 u