Question

How would you calculate the molar mass of water?

Answer 1

Hint The sum of the atomic masses of the atoms or elements present in the given molecule is known as molecular mass or atomic mass. We should know the atomic masses of all the elements involved in the formation of the molecule.

Complete step by step answer:
- In the question it is asked to calculate the molar mass of the water.
- The molecular formula of the water molecule is ${{H}_{2}}O$ .
- Means in water molecules there are two hydrogens and one oxygen atom.
- Means one mole of water is going to be formed by the reaction of two moles of hydrogen and one mole of oxygen atom.
- Mass of the one mole of hydrogen atom = 1 g per mole
- Mass of the one mole of oxygen atom = 16 g per mole
- Mass of the two moles of the hydrogen = (2) (1) = 2 g per mole.
- On adding the 2 moles of the hydrogen and one mole of oxygen gives the molar mass of the water molecule and it is as follows.
Molar mass of the one mole of water = 2 + 16 = 18 gram per mole.

- Therefore the molar mass of one mole of water is 18 gram per mole.

Note: We can calculate the molar mass of any compound if we know the atomic weight of the individual atoms or elements present in the respective compound. First we have to calculate the molecular weight, later we can calculate the molar mass of the compound.