Question

Calculate the molecular masses of the following:

(a) Hydrogen, $H_2$

(b) Oxygen, $O_2$

(c) Chlorine, $C{l}_2$

(d) Ammonia, $N{H}_3$

(e) Carbon dioxide, $C{O}_2$

(Atomic masses: H = 1 u, O = 16 u; Cl = 35.5 u; N = 14 u; C = 12 u)

Answer 1

a)molecular mass of H₂= 2× atomic mass of H
= 2×1 = 2 u.

b)molecular mass of O₂= 2× atomic mass of O
= 2 × 16u = 32 u.

c)molecular mass of Cl₂= 2 × atomic mass of Cl
= 2 × 35.5 u= 71 u.


d)molecular mass of NH₃= 14+ 3×1
= 17 u.

e)
molecular mass of CO₂= atomic mass of C + 2 × atomic mass of O
= 12 + 2×16
= 12+ 32= 44 u.