Fucking around (physical separation techniques) Flashcards
Physical separation techniques
Filtration
Crystallisation
Distillation
Chromatography
What are physical separation techniques used for?
Separating mixtures
But not compounds as they are bonded together
Filtration
Separating an insoluble (undissolved) solid from a liquid
How does filtration work?
Use filter paper in a filter funnel aiming into a beaker
Pour mixture through the funnel
So liquid passes through the tiny pours but solid stays in funnel
Crystallisation
Separates a soluble (dissolved) solid from a liquid
How can we determine whether to use crystallisation or filtration to separate a solid?
State symbol aq shows it’s dissolved
Meaning we must use crystallisation
But symbol s means it’s insoluble =filtration
How does crystallisation work?
Leave the mixture out so the liquid evaporates leaving the solid out of the beaker
How can we make crystallisation faster?
Heat gently
But make sure the chemical won’t break down due to heating
Simple distillation
Separating a soluble solid from a liquid whilst keeping the liquid
Because crystallisation evaporates away the liquid
How does simple distillation work?
Evaporate liquid away by heating
Condense the vapour released back to liquid by cooling
What apparatus used for distillation?
Mixture in a flask which is heated
Connected to a continuous glass tube
Which is surrounded by a condenser using cold water in and out to keep it cool
Thus when the gas moves through the tube it is cooled to a liquid then delivered into another beaker
Uses of simple distillation
Can be used to separate drinking water from sea water
Fractional distillation
Separating multiple liquids from each other
Each have a different boiling point
How does fractional distillation work?
Heating the liquid mixture
The liquids will continuously evaporate but condense again when they reach the column
This cycle increases amount of liquid with lower boiling point in the column
So it will rise through tube more making the temperature more favourable for lower bp
So lower by will condense first into beaker
Apparatus of fractional distillation
Same as simple distillation but with glass beads in the fractional column
