Question

Calculate the molecular masses of `H_(2), O_(2), Cl_(2), CO_(2), CH_(4), C_(2)H_(6), C_(2)H_(4), NH_(3), CH_(3)OH`.

Answer 1

Molecular mass of `H_(2)` = 2 × Atomic mass of H
= 2 × 1
= 2u
Molecular mass of `O_(2)` = 2 × Atomic mass of O
= 2 × 16
= 32u
Molecular mass of `Cl_(2)` = 2 × Atomic mass of Cl
= 2 × 35.5
= 71 u
Molecular mass of `CO_(2)` = Atomic mass of C + 2 × Atomic mass of O
= 12 + 2 × 16
= 44 u
Molecular mass of `CH_(4)` = Atomic mass of C + 4 × Atomic mass of H
= 12 + 4 × 1
= 16 u
Molecular mass of `C_(2)H_(6)` = 2 × Atomic mass of C + 6 × Atomic mass of H
= 2 × 12 + 6 × 1
= 30u
Molecular mass of `C_(2)H_(4)` = 2 × Atomic mass of C + 4 × Atomic mass of H
= 2 × 12 + 4 × 1
= 28u
Molecular mass of `NH_(3)` = Atomic mass of N + 3 × Atomic mass of H
= 14 + 3 × 1
=17 u
Molecular mass of `CH_(3)OH` Atomic mass of C+4 ×Atomic mass of H+Atomic mass of O
= 12 + 4 × 1 + 16
= 32 u