# Sodium sulfate has the formula Na₂SO₄. State what is meant by the term relative formula mass and calculate the relative formula mass of sodium sulfate. (Relative atomic masses: Na = 23, S = 32, O = 16)

> Pearson Edexcel International GCSE Chemistry (4CH1) — 1.4 Relative formula mass · State · 4 marks

## Mark scheme (4 marks)

1. Relative formula mass is the sum of the relative atomic masses of all the atoms in a formula
2. Correct identification/working: 2 × Na = 2 × 23 = 46
3. Correct identification/working: 1 × S = 1 × 32 = 32
4. Correct final answer of 142

## Key terms

- [relative formula mass](https://www.gradenine.co.uk/glossary/relative-formula-mass)
- [relative atomic mass](https://www.gradenine.co.uk/glossary/relative-atomic-mass)

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Source: [GradeNine](https://www.gradenine.co.uk/q/sodium-sulfate-has-the-formula-na-so-d3f4157f) · Published by Druglandscape Ltd.