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Relative Formula Mass

The relative formula mass is the mass of a formula unit compared to 1/12th the mass of a carbon-12 atom.
The relative formula mass of a formula unit is the sum of the relative atomic masses of the elements in the empirical formula.For example, the relative formula mass of sodium hydroxide NaOH is 23.0 + 16.0 + 1.0 which is 40.

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Specification: OCR Chemistry A (H032), AS-level, 2.1.3 Amount of substance. Topic: Amount of Substance.

Key terms in this lesson

Empirical formula
The simplest whole number ratio of atoms of each element in a compound.

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