A mint is choosing a gold material for a medallion that will be handled frequently. A steel point is pressed into each sample with the same force. A smaller dent depth indicates a harder material.
| Sample | Gold content in carats | Dent depth in mm |
|---|---|---|
| P | 24 | 0.62 |
| Q | 18 | 0.28 |
| R | 9 | 0.16 |
The material must have a dent depth no greater than 0.30 mm. The mint also wants the greatest possible proportion of gold.
Explain which sample should be used. Refer to the data and to the arrangement of atoms in the samples.
118 exam-style questions on AQA GCSE Chemistry 10.3 Using materials, covering 10.3.1 Corrosion and its prevention, 10.3.2 Alloys as useful materials, and 10.3.3 Ceramics, polymers and composites. Each one has a worked solution and a mark scheme showing where the marks go.