A manufacturer makes steel locking tabs. Each tab is pressed into shape during manufacture and must resist being permanently bent during use.
Four steel samples have the same dimensions.
| Sample | Carbon (% by mass) | Minimum force needed to permanently bend the sample (N) |
|---|---|---|
| P | 0.10 | 120 |
| Q | 0.25 | 180 |
| R | 0.60 | 320 |
| S | 1.00 | 470 |
Describe how the minimum force needed to permanently bend the steel changes as the percentage of carbon increases.
A fifth sample contains 0.80% carbon.
Predict whether this sample will be easier or harder to press into shape than sample Q.
Explain your prediction in terms of the arrangement of atoms.
The minimum force needed to permanently bend a locking tab must be greater than 300 N.
The manufacturer wants to use the sample that will be easiest to press into shape while meeting this requirement.
Suggest which sample should be used. Justify your answer using the data.
136 exam-style questions on OCR GCSE Chemistry 6.1 Improving processes and products, covering 6.1.1 Extracting metals industrially and by electrolysis, 6.1.2 Life cycle assessment and recycling, 6.1.3 Biological methods of metal extraction, 6.1.4 The Haber process and the production of fertilisers, 6.1.5 Alloys and their uses, 6.1.6 Corrosion and its prevention, 6.1.7 Comparing and selecting materials, and 6.1.8 Industrial conditions, rate and position of equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.