Calculate the formula unit masses of ZnO, Na2O, K2C03
(Given: Atomic masses of Zn = 65 u; Na = 23 u; K = 39 u; C = 12u and O = 16 u)
(i) Formula mass of ZnO = Mass of Zn atom + Mass of 0 atom
= 65 + 16 = 81 u
(ii) Formula mass of Na20 = Mass of 2Na atoms + Mass of 0
= 2 X 23 + 16 = 46 + 16 = 62 u
(iii) Formula mass of K2C03 = Mass of two potassium atoms + one carbon atom + three oxygen atoms = 2 X39 + 12+ 3 X16 = 78+ 12+ 48 = 138 u