Question

Calculate the formula unit mass of ZnO , Na2O , K2CO3 , given atomic masses of Zn = 65 u , Na =23 u , K = 39 u , C = 12 u , and O = 16 u .

Answer 1

Formula unit of ZnO

Atomic mass of Zn + atomic mass of O
= 65 +16= 81 u

Formula unit of Na2O

Atomic mass of Na2 + atomic mass of O
= (2 x 23 + 16) = 62 u

Formula unit of K2CO3

Atomic mass of K2 + atomic mass of C + atomic mass of O3
= (2 x 39 + 12 + 3 x 6)
= 138 u

Answer 2

Formula unit of ZnO

Atomic mass of Zn + atomic mass of O

= 65 +16= 81 u

Formula unit of Na2O

Atomic mass of Na2 + atomic mass of O

= (2 x 23 + 16) = 62 u

Formula unit of K2CO3

Atomic mass of K2 + atomic mass of C + atomic mass of O3

= (2 x 39 + 12 + 3 x 6)

= 138 u