Calculate the molar mass of the following substances.
(a) Ethyne, C₂H₂
(b) Sulphur molecule, S₈
(c) Phosphorus molecule, P₄ (Atomic mass of phosphorus = 31)
(d) Hydrochloric acid, HCl
(e) Nitric acid, HNO₃

The molar mass of the following substances are as follows:

(a) Ethyne, C₂H₂

Molar mass of ethyne

C₂H₂ = 2 x 12 + 2 x 1

Molar mass of ethyne = 26 g

(b) Sulphur molecule, S₈

Molar mass of sulphur molecule,

S₈ = 8 x 32 = 256 g

(c) Phosphorus molecule, P₄ (atomic mass of phosphorus = 31)

Molar mass of phosphorus molecule,

P₄ = 4 x 31 = 124 g

(d) Hydrochloric acid, HCl

Molar mass of hydrochloric acid,

HCl = 1 + 35.5 = 36.5 g

(e) Nitric acid, HNO₃

Molar mass of nitric acid,

HNO₃ = 1 + 14 + 3 x 16 = 63 g

[Extra information: Molar mass is defined as the mass of a substance for a given amount where the amount of the substance refers to the number of molecules or atoms or compounds present in one mole of a substance. The SI unit of the Molar mass of a substance is always caculated in is g/mol.]