A filter removes an unwanted gas by reacting it with a solid material. The reaction occurs only at the exposed surface of the material.
Each test used 8.0 g of the material, made into cubic particles of one size. The tests were carried out under the same conditions.
| Length of each side of a particle in nm | Time taken to remove a fixed amount of gas in minutes |
|---|---|
| 80 | 36 |
| 40 | 18 |
| 20 | 9.0 |
A filter currently contains 8.0 g of particles with sides of length 40 nm. The manufacturer proposes using 2.0 g of particles with sides of length 10 nm instead.
Both masses contain much more solid than is needed to remove the fixed amount of gas. The mass of solid that reacts during a test is negligible compared with the mass in either filter.
For this material, the total volume of the particles is proportional to their mass.
Explain, using the data and calculations, whether the proposed particles would be expected to remove the same amount of gas in the same time as the current particles.
104 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.