Molar Value Formula with Solved Example

Molar Value Formula

Molar mass is a bulk property of a substance. In chemistry, the molar mass of a chemical compound is described as a sample mass that can be divided by the amount of substance.

About the Topic

The formula to calculate the molar mass,

M = m/n 

M stands for molar mass

m stands for the mass of a substance

n is a number of a substance

The molar mass is a mixture of various materials important in polymer science. The molar mass of a compound is relative to atomic mass. The SI unit of molar mass is kg/mol, (M) is the Symbol used to define molar mass, and other units are g/mol.

There are two types of weight: one is molecular weight and the other is formula weight. Molecular weight is used as a synonym of molar mass, mainly for molecular compounds. The other weight is formula weight, which is also used as a synonym for molar mass and mainly for non-molecular compounds like ionic salts. 

The molar mass is the numerical value of one mole, which means if water is about 18.0162 daltons, its molecular mass will be 18.0162 g/mol. We can’t calculate molar mass directly; first, it has to be calculated in the form of standard atomic masses, and later it gets listed on chemical catalogues.

Generally, molar mass varies from 1–238 g/mol for naturally occurring elements of atoms. 10–1000 g/mol for simple chemical compounds. 1000–5000000 g/mol for polymers etc. 

Formula 

M = m/n

m = mass

n = molar mass 

Solved Example

• Calculate the number of moles in 3.01×10²² molecules of CO₂.

Mole Particle

1 mole = 6.022 X1023

X =3.01 X1022

3.01 X1022 = 6·022 x 1023   × X

1X3.01 X1022/6.022 X 1023  = X

X = 0.499×10-¹ atoms of nitrogen.

• Calculate the number of atoms.

(1) 0.5-mole atoms of nitrogen.

Mole Particle

1 mole= 6.022×1023

0.5 mole = X 

1 × X = 6.022×1023 x 0.5

X= 6.022×1023 x 0.5

X = 3.011 X1023 atoms of nitrogen.

(2) 0.2 mole of nitrogen.

Mole Particle

1 mole= 6.022 X1023

0.2mole= X

1X = 6.022× 1023 × 0.2 

X = 6.022× 1023 ×0.2

X= 1.2044× 10 23  are molecules of nitrogen

1 N molecule = 2 N atom

N atoms = 1.2044 × 1023× 2      

              = 2.4088× 1023 atoms of Nitrogen.