Separation of Solutions and Mixtures
Introduced| English |
|---|
| filtration/fɪlˈtreɪʃn/ |
| evaporation/ɪˌvæpəˈreɪʃn/ |
| distillation/dɪstɪˈleɪʃn/ |
| chromatography/krəʊməˈtɒɡrəfi/ |
Pulling a blend apart
- A muddy river can be made clear again.
- Salt can be recovered from the sea by the sun.
- Ink can be split into its hidden colours.
- Each trick exploits one way the parts differ.
Filtration and evaporation
- Filtration 过滤 separates by particle size: solids are caught, liquid passes.
- Evaporation 蒸发 leaves a dissolved solid behind as the solvent boils off.
- Use filtration for undissolved solids, evaporation for dissolved ones.
Filtration separates a mixture based on differences in...
Large solids are trapped while liquid passes through the filter.
To recover dissolved salt from salt water while discarding the water, use...
Boiling off the water leaves the solid salt behind.
Distillation
- Distillation 蒸馏 separates liquids by their boiling points.
- The lower-boiling liquid vaporizes first, then re-condenses cleanly.
- It is how alcohol is separated from water.
To separate pure water from salt water, you would use...
Distillation boils off the water and re-condenses it, leaving salt behind.
Chromatography
- Chromatography 色谱法 separates by how strongly each part clings to a surface.
- The components travel at different speeds and spread out.
- Ink's dyes separate into a rainbow of bands.
Pick the separation method
Match each mixture to the technique that separates it, and the property it exploits.
Match each method to the property it uses.
Distillation = boiling point, filtration = size, chromatography = affinity.
Chromatography separates ink dyes because each travels at a different ____.
Dyes that cling more strongly move more slowly, so they spread apart.
How would you get pure water from salt water?
- Distil it: boil the water off and re-condense the vapour.
- The salt stays behind, and the collected liquid is pure water.
Filtration can separate a dissolved solute from its solvent.
Dissolved particles pass through the filter; use evaporation or distillation.
Each method exploits one specific difference -- size for filtration, boiling point for distillation, surface affinity for chromatography. Filtration cannot separate a dissolved solute (it passes through the filter); use evaporation or distillation for that. Match the method to the property that differs.
Separation methods each exploit a property difference: filtration by particle size, evaporation to recover a dissolved solid, distillation by boiling point, and chromatography by surface affinity. A dissolved solute passes through a filter, so recover it by evaporation or distillation instead.