Question

What is the molecular mass of a substance, each molecule of which contains 9 atoms of carbon, 13 atoms of hydrogen and 223 × 10^–23 g of other component?

Answer 1

Mass of 9 atoms of carbon = 12 × 9

= 108 u

Mass of 13 atoms of hydrogen = 1 × 13

= 13 u

Mass of 2.33 × 10^–23 g of other component

= (1 u) x \(\frac{(2.33\times10^{-23})}{(1.66\times10^{-24}g)}\) = 14.04 u

\(\therefore\) Molecular mass of substance

= 108 + 13 + 14.04

= 135.04 u