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

Formula unit mass of ZnO = Atomic mass of Zn + Atomic mass of O
= 65 + 16
= 81 u
Formula unit mass of `Na_(2)O` = 2 × Atomic mass of Na + Atomic mass of O
= 2 × 23 + 16
= 62u
Formula unit mass of `K_(2)CO_(3)` = 2 × Atomic mass of K + Atomic mass of C + 3 × Atomic mass of O
= 2 × 39 + 12 + 3 × 16
=78 + 12 + 48
= 122 u