Question

Calculate the formula unit masses of ZnO, `Na_(2)O, K_(2)CO_(3)`, given atomic masses of Zn = 65 u, Na = 23 u, K = 39 u, C = 12 u, and O = 16 u.

Answer 1

(i) Formula mass of `ZnO =` Mass of Zn atom + Mass of O atom
`= 65 + 16`
`= 81 u`
(ii) Formula mass of `Na_(2)O =` Mass of 2Na atoms + Mass of O
`= 2 xx 23 + 16`
`= 46 +16`
`= 62 u`
(iii) Formula mass of `K_(2)CO_(3)` (See Sample Problem on page `138` of this book).