A technician is selecting a carbon coating for the front of a light sensor. The coating must transmit at least 90% of the incident light and conduct electricity.
One coating is graphene and the other is graphite.
| Coating | Incident light transmitted (%) | Conducts electricity |
|---|---|---|
| P | 97 | Yes |
| Q | 8 | Yes |
Select the coating that should be used and justify your choice using both requirements. Identify the form of carbon in each coating.
Describe how the structures and bonding in the two forms of carbon account for the results.
122 exam-style questions on OCR GCSE Chemistry 2.3 Properties of materials, covering 2.3.1 Carbon bonding and the variety of organic compounds, 2.3.2 Diamond, graphite, fullerenes and graphene, 2.3.3 Bond strength, changes of state and predicting states, 2.3.4 Bulk properties and types of bonding, and 2.3.5 Nanoparticles: scale, surface area, uses and risks. Each one has a worked solution and a mark scheme showing where the marks go.