Separating Mixtures Flashcards
What are the five methods for separating mixtures?
SimpleDistillation Fractional Distillation Filtration Crystallisation Paper Chromatography
What is distillation?
Separation of mixtures of liquids due to their different boiling points.
How does simple distillation differ from fractional distillation?
Simple distillation separates two liquids, fractional separates many liquids using a fractionating column.
Where is hottest and coldest in a fractionating column?
Hottest at the bottom, coldest at the top.
How does filtration work?
Filter paper separates insoluble solids from liquids.
Describe how crystallisation works.
Solution is warmed
Solvent evaporates.
Leaves concentrated solution until no more solvent remains.
Solid crystals form.
What is crystallisation used for?
Producing solid crystals that were dissolved in solution.
How can you make bigger crystals in crystallisation?
Heat more slowly/gently.
Stop heating before all solvent evapourates and then air dry.
What does paper chromatography do?
Separates mixtures of soluble substances
How does chromatography work?
Each part of the mixture is attracted to the mobile and stationary phase by different amounts, causing it to move by a different amount up the chromatography paper.
What is the line drawn with in chromatography?
Pencil!
What are the two phases in chromatography?
Stationary phase
Mobile phase
What is the stationary phase in chromatography?
The paper
What is the mobile phase in chromatography?
The solvent
What does a pure substance look like in chromatography?
A single dot because it doesn’t separate into different parts if it is pure.
