# Explain how Avogadro's constant relates the macroscopic scale of measurement (grams) to the sub-microscopic scale (individual atoms or molecules), using the element carbon-12 as your reference point.

> IB DP Chemistry Standard Level (2023 syllabus) — S1.4 Counting particles by mass: The mole · Explain · 4 marks

## Mark scheme (4 marks)

1. One mole of carbon-12 has a mass of exactly 12 g (linking macroscopic mass to a defined amount of substance).
2. Avogadro's constant (Nₐ ≈ 6.02 × 10²³ mol⁻¹) is defined as the number of atoms in exactly 12 g of carbon-12.
3. Avogadro's constant acts as a conversion factor between the number of individual particles (sub-microscopic) and the amount in moles (macroscopic).
4. Because the relative atomic mass of any element numerically equals its molar mass in grams, any element's molar mass can be measured on a balance (macroscopic) and directly corresponds to one mole of atoms (sub-microscopic).

## Key terms

- [Avogadro's constant](https://www.gradenine.co.uk/glossary/avogadro-s-constant)
- [mole](https://www.gradenine.co.uk/glossary/mole)
- [carbon-12](https://www.gradenine.co.uk/glossary/carbon-12)

## Related

- [Revision notes for IB DP Chemistry Standard Level (2023 syllabus)](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/explain-how-avogadro-s-constant-relates-the-a0371619) · Published by Druglandscape Ltd.