In I/GCSE Chemistry, you will have to know the definition to these basic terms...
- A solution = mixture made of solutes in a liquid/solvent
- Solutes = dissolved substances
- Solvent = liquid
- Saturated solution = it contains the maximum amount of solute that can dissolve in that amount of solvent at that temperature.
- Solutes can be separated from a solution by evaporating the solvent to leave the solutes behind. This is crystallisation.
- The process forms solid crystals of various sizes.
- If the crystals form slowly, the particles have longer to form an ordered pattern and will make larger crystals.
- Filtration can be used to separate mixtures.
- They let smaller pieces or liquids through, but trap bigger pieces/substances or insoluble substances.
- Example: Separating rocks from water. The filter paper will allow the liquid/water to pass through it while retaining/trapping the insoluble substance, which in this case would be the rocks.
Filtration and crystallisation in the lab: 🧪
- In the laboratory, a filter funnel is lined with filter paper that has fine holes in it. The solvent will pass through the fine holes to form the filtrate. Bits of insoluble substances cannot fil through the holes and so leave a residue in the filter paper. -FILTRATION
- A Bunsen burner is used to evaporate the filtrate carefully.
- Must not overheat the solution once it is saturated, as hot crystals may spit out.
- Further heating may also cause crystals to change chemically.
Drafted by Catrina (Chemistry)