Question

The molecular weight of each element is determined by the

Answer 1

Answer :

Molecular weight of of each element is determined by the molecular mass of a substance which is the relative mass of its molecule as compared with the mass of a carbon atom taken as 12 units.

Calculation of Molecular Weight

The molecular weight is equal to the sum of the the atomic masses of all the atoms present in one molecule of the substance. For example, one molecule of water contains two atom of Hydrogen and one atom of Oxygen. So, the molecular mass of water will be equal to the sum of the masses of two Hydrogen atoms and one Oxygen atom.

Mass of H atoms = 1g

Mass of 2H atoms = 2 ×1g = 2 g

Mass of O atoms = 16g

Now, molecular weight of H2O = mass of 2H atoms + mass of O atom = 2g + 16g = 18g.

.°. Molecular weight of H2O = 18g