Q 2. 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
Given,
the atomic mass of Zn = 65 u,
the atomic mass of Na = 23 u,
the atomic mass of K = 39 u,
the atomic mass of C = 12 u,
and the atomic mass of O = 16 u
Now,
Formula unit mass of ZnO = Atomic mass of Zinc + Atomic mass of O
= 65 u + 16 u
= 81 u.
Formula unit mass of Na2O = 2 * Atomic mass of Na+ Atomic mass of O
= 2 * 23 u + 16 u
= 62 u.
Formula unit mass of K2CO3 = 2 * Atomic mass of K+ Atomic mass of C + 3 * Atomic mass of O
= 2 * 39 u + 12 u + 3 * 16 u
= 138 u.