WJEC GCSE Chemistry Practice Exam

Separating by particle size works when a barrier with tiny holes lets smaller particles and liquids pass while larger particles are trapped. Filtration uses a filter paper or membrane so that the mixture, like muddy water, flows through, but the solid bits stay behind on the filter. This relies on the physical size of the particles, not their boiling points or densities. Evaporation and distillation separate stuff by changing state or by volatility, not by how big the particles are, and centrifugation relies on density and spinning to separate components rather than just size.