Nanoparticles of titanium dioxide are used in sunscreens.
Which property makes them suitable for this use?
They block ultraviolet light but do not leave a white layer on the skin.
They conduct electricity well because they have delocalised electrons.
They kill bacteria on the skin because they contain silver atoms.
They have a high melting point so they do not melt in strong sunlight.
60 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.