# Iron is extracted from iron ore in a blast furnace. However, pure iron is rarely used in construction. Instead, iron is converted into steel, an alloy. Explain why steel is more useful than pure iron for construction purposes, and describe one way in which the composition of steel can be changed to make it suitable for a specific use.

> OCR A-Level Chemistry B: Salters (H433) — DM Developing metals · Explain · 5 marks

> Steel is one of the most widely used materials in the world. It is produced by altering the composition of iron extracted from the blast furnace. Different types of steel can be made by changing what is added to the iron.

## Mark scheme (5 marks)

1. Pure iron has a regular arrangement of atoms/layers that can slide over each other easily
2. This makes pure iron soft/too malleable/easily deformed, so it is not strong enough for construction
3. In steel, other atoms (e.g. carbon) are added which distort the regular arrangement / disrupt the layers
4. This makes steel harder/stronger/less easy to deform than pure iron
5. A named example of how steel composition can be changed for a specific use, e.g. adding more carbon to make high-carbon steel which is harder/used for cutting tools; or adding chromium/nickel to make stainless steel which is corrosion-resistant/used for cutlery or medical instruments

## Key terms

- [alloy](https://www.gradenine.co.uk/glossary/alloy)
- [pure iron](https://www.gradenine.co.uk/glossary/pure-iron)
- [steel](https://www.gradenine.co.uk/glossary/steel)

## Related

- [Revision notes for OCR A-Level Chemistry B: Salters (H433)](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/iron-is-extracted-from-iron-ore-c613f838) · Published by Druglandscape Ltd.