Some sunscreens contain nanoparticles of titanium dioxide instead of larger, bulk particles of titanium dioxide.
Statement 1: the nanoparticles can give better skin coverage because they have a much larger surface area to volume ratio
Statement 2: the nanoparticles behave differently because they are made of a different compound from bulk titanium dioxide
Statement 3: bulk titanium dioxide is safe on skin, so the nanoparticles must also be safe on skin
Statement 4: the nanoparticles may be able to enter cells, and their long-term effects are not yet fully known
Which statements are correct?
1 and 4 only
4 only
1, 3 and 4 only
1, 2 and 4 only
36 exam-style questions on Edexcel GCSE Chemistry 10.5 Bulk and surface properties of matter including nanoparticles, covering 10.5.1 Nanoparticles: size, uses and risks and 10.5.2 Comparing and selecting materials. Each one has a worked solution and a mark scheme showing where the marks go.