Q.:- Calculate the formula unit masses 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:-

Formula unit mass of  ZnO = atomic mass of  Zn + atomic mass of O

=(65 + 16)u = 81u

Formula unit mass of  Na₂O = 2 X atomic mass of Na + atomic mass of O

=(2 X 23 +16)u = 62u

Formula unit mass of  K₂CO₃ = 2 X atomic mass of  K + atomic mass of C + 3 X atomic mass of O

=(2 X 39 +12 + 3 X 6)u = (78 + 12 + 48)u = 138u