## Molar Mass Formula :

Molar mass_{(}_{kg/ mol)} in kilogram per mole is equal to the product of the mass_{(g)} in gram is divided by mole. Hence the molar mass formula has been written as,

Molar mass_{(}_{kg/ mol)} = mass_{(g)} / mole

= g/mol

Units of Molar Mass: SI unit is kg/ mol or gm/mol.

## Sample Problems :

### Example 1:

What is the molar mass of Sodium Carbonate?

### Solution :

The chemical formula of Sodium Carbonate is Na_{2}CO_{3}. It contains two sodium atoms, one carbon atom and three oxygen atoms.

We know that the molecular weight of Sodium (Na) is 22.98g/mol, Carbon (C) is 12.011 g/mol and Oxygen (O) is 16 g/mol.

Therefore, the molar mas of sodium carbonate is

Na = 2 * 22.98

= 45.96 g/mol.

C = 1 * 12.011

= 12.011 g/mol.

O = 3 * 16

= 48 g/mol.

By adding all we get

= 45.96 + 12.011 + 48

= 105.971

Therefore, the molar mass of Na_{2}CO_{3} is 105.971 g/mol.

### Example 2:

What is the molar mass of Hydrochloric Acid?

### Solution :

The chemical formula of Hydrochloric acid is HCl. It contains one Hydrogen atom, one chlorine atom.

We know that the molecular weight of Hydrogen (H) is 1.0078g/mol, Chlorine (Cl) is 35.453 g/mol.

Therefore, the molar mas of hydrochloric acid is

H = 1 * 1.0078

= 1.0078 g/mol.

Cl = 1 * 35.453

= 35.453g/mol.

By adding all we get

= 1.0078 + 35.543

= 36.460 g/mol.

Therefore, the molar mass of HCl is 36.460 g/mol.