Lenses for glasses are often given a coating that resists scratching. The coating contains a hard substance. The coating can be made using nanoparticles of the hard substance or fine particles of the hard substance.
Explain why nanoparticles of the hard substance are used instead of fine particles.
The coating made using nanoparticles is transparent, but the coating made using fine particles is not.
Suggest why a transparent coating is an advantage for a lens.
40 exam-style questions on AQA GCSE Chemistry 2.4 Bulk and surface properties of matter including nanoparticles, covering 2.4.1 Sizes of particles and their properties and 2.4.2 Uses of nanoparticles. Each one has a worked solution and a mark scheme showing where the marks go.