# A teacher shows two samples to a class: one mole of copper atoms and one mole of sulfur atoms. A student claims that both samples contain the same mass. State whether the student is correct or incorrect, and explain why, referring to the mole and the Avogadro constant in your answer.

> Cambridge International IGCSE Chemistry (0620) — 3.3 The mole and the Avogadro constant · Explain · 4 marks

## Mark scheme (4 marks)

1. The student is incorrect.
2. One mole of any substance contains the same number of particles (6.02 × 10²³), equal to the Avogadro constant.
3. The mass of one mole equals the relative atomic mass expressed in grams (the molar mass).
4. Copper has a different (relative atomic) mass to sulfur, so the two samples have different masses (copper: 64 g; sulfur: 32 g).

## Key terms

- [mole](https://www.gradenine.co.uk/glossary/mole)
- [Avogadro constant](https://www.gradenine.co.uk/glossary/avogadro-constant)

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" 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/a-teacher-shows-two-samples-to-5f7165b3) · Published by Druglandscape Ltd.