# Iron(III) oxide has the formula Fe₂O₃. State what is meant by the term relative formula mass and use the formula of iron(III) oxide to show how the relative formula mass is determined. (Relative atomic masses: Fe = 56, 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 atoms in the formula (of the compound)
2. Correctly identifies the number of each type of atom: 2 Fe atoms and 3 O atoms
3. Correct multiplication: 2 × 56 = 112 for iron, and 3 × 16 = 48 for oxygen
4. Correct final answer of 160

## 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)
- [formula](https://www.gradenine.co.uk/glossary/formula)

## Related

- [Revision notes for Pearson Edexcel International GCSE Chemistry (4CH1)](https://www.gradenine.co.uk/learn)
- [How to answer "State" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/iron-iii-oxide-has-the-formula-fe-o-d16ab419) · Published by Druglandscape Ltd.