How is the relative molecular mass calculated?

The relative molecular mass, also known as molecular weight, is calculated by adding together the relative atomic masses of all the atoms present in a molecule. Each element has a specific atomic mass, which can typically be found on the periodic table. When determining the molecular mass, you consider the number of each type of atom within the molecule and multiply the atomic mass of each atom by its quantity.

For example, in water (H₂O), the relative molecular mass is calculated by taking two times the atomic mass of hydrogen (approximately 1.01) and adding that to one times the atomic mass of oxygen (approximately 16.00). So, the calculation would be (2 x 1.01) + (1 x 16.00) = 2.02 + 16.00 = 18.02 g/mol.

Understanding this calculation helps in various applications, such as stoichiometry in chemical reactions, where precise amounts of reactants and products are often needed.