Seperation Techniques Flashcards
What is simple distillation used for?
Simple distillation is used to separate a liquid and soluble solid from a solution or a pure liquid from a mixture of liquids.
Example: Separating water from a solution of salt water.
How does simple distillation work?
The solution is heated, causing pure water to evaporate into a vapour that rises through the neck of the flask. The vapour then cools and condenses in the condenser, turning into a pure liquid collected in a beaker.
What happens after all the water is evaporated in simple distillation?
Only the solid solute will be left behind.
What is fractional distillation used for?
Fractional distillation is used to separate two or more miscible liquids.
How does fractional distillation work?
The solution is heated to the temperature of the substance with the lowest boiling point, which evaporates first. The vapours pass through a condenser, cool, and condense into a liquid collected in a beaker.
What is the boiling point of ethanol and water?
Ethanol has a boiling point of 78 ºC and water has a boiling point of 100 ºC.
What is filtration used for?
Filtration is used to separate an undissolved solid from a mixture of the solid and a liquid.
How does filtration work?
A mixture is poured into a filter funnel lined with filter paper, allowing small liquid particles to pass through as filtrate while solid particles remain as residue.
What is crystallisation used for?
Crystallisation is used to separate a dissolved solid from a solution when the solid is much more soluble in hot solvent than in cold.
How do you test if a solution is saturated in crystallisation?
Dip a clean, dry, cold glass rod into the solution. If saturated, crystals will form on the rod.
What is paper chromatography used for?
Paper chromatography is used to separate substances with different solubilities in a given solvent.
How is paper chromatography performed?
A pencil line is drawn on chromatography paper, and spots of the sample are placed on it. The paper is then lowered into the solvent, allowing the solvent to travel up the paper by capillary action.
What indicates the purity of a substance in paper chromatography?
An impure substance will show more than one spot, while a pure substance will show only one spot.
