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=(Zinc oxide)
`=(1xx "Atomic mass of Zn")+(1xx "Atomic mass of O")`
`=-(1xx65u)+(1xx16u)=81u`
(ii) Formula unit mass of `Na_(2)O` (sodium oxide)
`=(2xx "Atomic mass of K")+(1xx "Atomic mass of O")`
`=(2xx23u)+(1xx12u)+(3xx16u)=138u`