Question

Calculate the formula unit massese of ZnO Na2O,k2CO3 given atomic masses if Zn=56u Na=23u,K =39u ,C=12u and O=16u. ​

Answer 1

$(i) \: ZnO = 56 + 16 = 72 \: u$

$(ii) \: Na_{2}O = (2 \times 23) + 16 = 46 + 16 = 62 \: u$

$(iii) \: K_{2}CO_{3} = (2 \times 39) + 12 + (3 \times 16) = 78 + 12 + 48 = 138 \: u$

Answer 2

Explanation:

Given:

Atomic mass of Zn = 65u

Atomic mass of Na = 23u

Atomic mass of K = 39u

Atomic mass of C = 12u

Atomic mass of O = 16u

The formula unit mass of ZnO= Atomic mass of Zn + Atomic mass of O = 65u + 16u = 81u

The formula unit mass of Na2O = 2 x Atomic mass of Na + Atomic mass of O = (2 x 23)u + 16u = 46u + 16u = 62u

The formula unit mass of K2CO3 = 2 x Atomic mass of K + Atomic mass of C + 3 x Atomic mass of O = (2 x 39)u + 12u + (3 x 16)u = 78u + 12u + 48u = 138u