# Molecular Weight Formula

## Molecular Weight Formula

The total atomic masses of all the atoms in a molecule make up its Molecular Weight Formula. It is calculated in atomic mass units (amu or u). We can also find out how many grams of a substance are included in one mole of a compound by looking at its Molecular Weight Formula. Therefore, it is the sum of the atomic weights of all the atoms in a given molecule of a given chemical compound. As an instance, the Molecular Weight Formula of Oxygen (O2) will be 32 because that is the sum of all the atomic weights that make up one oxygen atom. The Molecular Weight Formula is a representation of the atoms present in a specific molecule, as well as the number of those atoms. The number of atoms of an element present in a molecule is indicated by the atomic symbol and the subscript that appears beneath it. For instance, O2 and C4 are the molecules of oxygen and carbon, respectively.

What is Molecular Weight?

Molecules are composed of one or more atoms. The various atoms that make up a molecule determine the mass of the molecule. The molecular mass is the total mass of the molecule. It is expressed in Daltons. It is also known as molar mass, molecular weight, and molecular mass. A D alton is the relative mass of the carbon-12 isotope. The weight of the carbon-12 isotope is calculated as the weight of an atomic mass unit and divided by 12. Knowing how many grams are contained in one mole of a substance requires knowledge of its molecular mass or weight. The Molecular Weight Formula of a single element is the total atomic weights of all the atoms of that element needed to make a stable molecule. For instance, the molecular weight of O2, which is the total of one Oxygen atom’s atomic weight, is 32. Similarly, iron, which is made up of a single atom, has a molecular weight of 56.

How to Calculate Molecular Weight Formula?

Simply multiplying the number of each type of atom present in a molecule by its atomic weight and adding the weights of other atoms will yield the molecular weight of an element. A given molecule’s molecular weight is calculated by adding the atomic weights of all its constituent atoms. The molecular formula is an easy way to find this information. As a result, the definition and Molecular Weight Formula can both be obtained from the molecular formula of a particular molecule. The sum of all the atoms in a given molecule, which can be determined from its molecular formula, is what makes up the Molecular Weight Formula.

### Given Below are two Examples About How to Calculate Molecular Weight

Example 1: Calculate the Molecular Weight Formula of NaCl.

Solution: Molecular Weight of Na = 23

Molecular Weight of Cl = 35

No. of Na molecules = 1

No. of Ca molecules = 1

Hence, total molecular weight of NaCl = 23(1) + 35(1) = 58

Example 2: Calculate the Molecular Weight Formula of C6H6.

Solution: It is evident from the above molecular formula that the given chemical compound contains 6 carbon atoms and 6 hydrogen atoms. Hence, the atomic weights of hydrogen and carbon are 1.008 and 12.0107, respectively.

Thus, the molecular weight of C6H6 is  = 6*(atomic weight of carbon) + 6*(atomic weight of hydrogen)

= 6*(12.0107 amu) + 6*(1.008 amu)

=  72.0642 amu + 6.048 amu

= 78.112 amu.