Relative Formula Mass - GCSE Chemistry

The relative formula (molecular) mass is equal to the sum of the relative atomic masses of all the atoms in a formula.

Author: Mr. Rich Pepperell

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Video Notes:
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- Relative formula mass = The sum of the relative atomic masses of each atom in the formula.
- Relative atomic mass = Average mass of the atom.

The Law of Conservation of Mass states that Total mass of reactants = Total mass of products

The law of conservation of mass says that no atoms can be created or destroyed in a chemical reaction. Therefore, the total mass of reactants must equal the total mass of products.

Calculating the Relative Formula Mass (Mr)
To calculate the relative formula mass of a compound, we need to know the relative atomic masses (Ar) of the elements that make the compound. Then we multiply the Ar values by the number of atoms of that element in the compound. Then we add these numbers together.