Calculate the molar mass

Question.
Calculate the molar mass of the following substances

(a) Ethyne, $\mathrm{C}_{2} \mathrm{H}_{2}$

(b) Sulphur molecule, $S_{8}$

(c) Phosphorus molecule, $\mathrm{P}_{4}$ (atomic mass of phosphorus $=31$ )

(d) Hydrochloric acid, $\mathrm{HCl}$

(e) Nitric acid, $\mathrm{HNO}_{3}$


Solution:

(a) Molar mass of ethyne, $\mathrm{C}_{2} \mathrm{H}_{2}=2 \times 12+2 \times 1=26 \mathrm{~g}$

(b) Molar mass of sulphur molecule,

$\mathrm{S}_{\mathrm{g}}=8 \times 32=256 \mathrm{~g}$

(c) Molar mass of phosphorus molecule,

$P_{4}=4 \times 31=124 \mathrm{~g}$

(d) Molar mass of hydrochloric acid,

$\mathrm{HCl}=1+35.5=36.5 \mathrm{~g}$

(e) Molar mass of nitric acid.

$\mathrm{HNO}_{3}=1+14+3 \times 16=63 \mathrm{~g}$

Leave a comment