Molar Mass Formula With Solved Examples

Molar Mass Formula

The molar mass formula is a measure to find out the mass of one mole of a molecule (or a compound). This article will enable the learners to compute the molar mass of any molecule (or a compound) with conceptual clarity.

What Is Molar Mass?

The molar mass is defined as the mass of the molecules of the compound. It is measured in the unit of kg/ mole or gram/ mole. The molar mass of the compound is the mass of a given substance divided by the quantity of the substance in a sample. It is an intensive property of the substance. 

The molar mass formula is defined as the mass of the given element divided by the number of moles of that element. In other words, the molar mass formula can be defined as the sum of the atomic mass of all the atoms present in the molecule.

What is the Molar Mass Formula?

• To calculate the molar mass of the compound, first, we need to know the atomic mass of the elements that constitute the compound. 
• Next, we need to know the number of atoms present in that element in the compound. 
• Then we can calculate the molar mass of the compound by adding the atomic mass of all the atoms present in the molecule or by the formula mentioned below. 

M = mn

Where: M = Molar mass of the compound

  m = Mass of the compound

  n = The number of moles in the compound

Solved Examples

• The Molar mass formula of Chlorine (Cl2)  

The molecule Chlorine is composed of two atoms. As we know that the molar mass of a molecule is the atomic mass of the element multiplied by the number of atoms, so the molar mass of chlorine (Cl2) molecule will be calculated as 35.5 (approx) x 2 which comes out to be 70 grams per mole. 

Hence, the molar mass of Chlorine (Cl2) is 71 grams/ mole (approx).

• The Molar mass formula of Sucrose (C12H22O11)

Th molar mass of C12H22O11 will be calculated by taking the sum of the atomic mass of carbon i.e  12 multiplied by the number of carbon atoms present in the molecule i.e 12 and the atomic mass of hydrogen i.e 1 multiplied by the number of hydrogen atoms i.e 22 and the atomic mass of Oxygen i.e 16 multiplied by its number of atoms i.e 11 which comes out to be 342 gram per mole [(12×12) + (1×22) + (16×11)].

Hence, the molar mass of Sucrose (C12H22O11) is 342 grams/ mole.