Question

Calculate the molecular masses of H₂, O₂, Cl₂, CO₂, CH₄, C₂H₆, C₂H₄, NH_3, CH₃OH.

Answer 1

Molecular mass of H₂ = 2 × Atomic mass of H 

= 2 × 1 = 2u 

Molecular mass of O₂ = 2 × Atomic mass of O 

= 2 × 16 = 32u 

Molecular mass of Cl₂ = 2 × Atomic mass of Cl 

= 2 × 35.5 = 71 u 

Molecular mass of CO₂ = Atomic mass of C + 2 × Atomic mass of O 

= 12 + 2 × 16 = 44 u 

Molecular mass of CH₄ = Atomic mass of C + 4 × Atomic mass of H 

= 12 + 4 × 1 = 16 u 

Molecular mass of C₂H₆ = 2 × Atomic mass of C + 6 × Atomic mass of H 

= 2 × 12 + 6 × 1 = 30u 

Molecular mass of C₂H₄ = 2 × Atomic mass of C + 4 × Atomic mass of H 

= 2 × 12 + 4 × 1 = 28u 

Molecular mass of NH₃ = Atomic mass of N + 3 × Atomic mass of H 

= 14 + 3 × 1 =17 u 

Molecular mass of CH₃OH Atomic mass of C+4 ×Atomic mass of H+Atomic mass of O = 12 + 4 × 1 + 16 = 32 u