What is the molecular mass of H2O?

A. 39 g/mol

B. 29 g/mol

C. 18 g/mol

D. 09 g/mol

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Calculation of Molecular Mass of H2O

Water has (H2O) has 2 elements i.e H and O

We know that

Mass of 1 mole of Hydrogen atoms= 1 g /mol
Mass of 1mole of Oxygen atoms = 16 g/mol

As there are two Hydrogen

So, Mass of two moles of Hydrogen atoms = 2x 1 g/mol = 2 g/mol.
Mass of one mole of Oxygen atoms = 1 x 16 g /mol

By adding the molar masses of all the elements,

Mass of one mole of water = 2 g/mol + 16 g/mol = 18 g/mol.


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