Premium Online Home Tutors
3 Tutor System
Starting just at 265/hour
Answer :
Given, atomic masses of Zn = 65u, Na = 23u, K = 39u, C = 12u, O = 16u
We know that formula unit mass of a substance is the sum of the atomic masses of all the atoms in the formula unit of the substance.
So, the formula unit mass of ZnO = Atomic mass of Zn + Atomic mass of O = 65 + 16 = 81u
The formula unit mass of Na\( _2 \)O = 2 × Atomic mass of Na + Atomic mass of O = (2 × 23) +16 = 46 + 16 = 62u
The 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 = 138u