Nanoparticles of cerium oxide can be added to diesel fuel. They act as a catalyst to help the fuel burn more completely.
In one sample, the nanoparticles are cubes with a side length of 40 nm.
In an ordinary cerium oxide powder, the particles are cubes with a side length of 4.0 µm.
Calculate how many times larger the surface area to volume ratio of the nanoparticles is than that of the ordinary powder.
The diameter of an atom is about 2 × 10⁻¹⁰ m.
Estimate the number of atoms along one edge of a nanoparticle with a side length of 40 nm.
Explain why a smaller mass of cerium oxide is needed when it is added to the fuel as nanoparticles rather than as ordinary powder.
Some scientists are concerned about adding nanoparticles to diesel fuel.
Explain the possible risks.
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.