Calculate the molecular mass of the following in u :i. H2O ii. C6H5Cl

1.	Calculate the molecular mass of the following in u :i. H2O ii. C6H5Cl iii. H2SO4
Answer» i. Molecular mass of H₂O = (2 × Average atomic mass of H) + (1 × Average atomic mass of O) = (2 × 1.0u) + (1 × 16.0 u) = 18 u ii. Molecular mass of C₆H₅Cl = (6 × Average atomic mass of C) + (5 × Average atomic mass of H) + (1 × Average atomic mass of Cl) = (6 × 12.0 u) + (5 × 1.0 u) + (1 × 35.5 u) = 112.5 u iii. Molecular mass of H₂SO₄ = (2 × Average atomic mass of H) + (1 × Average atomic mass of S) + (4 × Average atomic mass of O) = (2 × 1.0 u) + (1 × 32.0 u) + (1 × 16.0 u) = 98 u ∴ i. The molecular mass of H₂O = 18 u ii. The molecular mass of C₆H₅Cl = 112.5 u iii. The molecular mass of H₂SO₄ = 98 u

Calculate the molecular mass of the following in u :i. H2O ii. C6H5Cl iii. H2SO4

Answer»

i. Molecular mass of H₂O = (2 × Average atomic mass of H) + (1 × Average atomic mass of O)

= (2 × 1.0u) + (1 × 16.0 u)

= 18 u

ii. Molecular mass of C₆H₅Cl = (6 × Average atomic mass of C) + (5 × Average atomic mass of H) + (1 × Average atomic mass of Cl)

= (6 × 12.0 u) + (5 × 1.0 u) + (1 × 35.5 u)

= 112.5 u

iii. Molecular mass of H₂SO₄ = (2 × Average atomic mass of H) + (1 × Average atomic mass of S) + (4 × Average atomic mass of O)

= (2 × 1.0 u) + (1 × 32.0 u) + (1 × 16.0 u)

= 98 u

∴ i. The molecular mass of H₂O = 18 u

ii. The molecular mass of C₆H₅Cl = 112.5 u

iii. The molecular mass of H₂SO₄ = 98 u