Nanoparticles of platinum are used as catalysts.
A mass of platinum nanoparticles is a better catalyst than the same mass of larger platinum particles.
Why?
They have a larger surface area to volume ratio, so more atoms are exposed.
They are made of a different type of platinum atom that is more reactive.
They have a smaller surface area to volume ratio, so they last for longer.
They contain more platinum atoms in total than the larger particles.
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.