Question

Calculate the molecular masses of ${\text{H}}_2,{\text{O}}_2,{\text{CO}}_2,{\text{NH}}_3.$

Answer 1

1. Molecular mass of ${\text{H}}_2$ = 2 x Atomic mass of H

= 2 x 1 u

= 2 u

2. Molecular mass of ${\text{O}}_2$= 2 x Atomic mass of O

= 2 x 16 u

= 32 u

3. Molecular mass of ${\text{CO}}_2$= Atomic mass of C + 2 x Atomic mass of O

= 12 u + 2 x 16 u

= 44 u

4. Molecular mass of ${\text{NH}}_3$ = Atomic mass of N + 3 x Atomic mass of H

= 14 u + 3 x 1 u

= 17 u