Separating Substances Flashcards
What does filtration separate?
An insoluble solute and a solvent
What does crystallisation separate?
A soluble solute from a solvent
What does simple distillation separate?
A soluble solute and a solvent
OR
Two liquids
What does paper chromatography separate?
A mixture of soluble substances
How would you calculate an Rf value?
Distance moved by solute (ink)
——————————————
Distance moved by solvent
In paper chromatography, what is the stationary phase?
The chromatography paper
In paper chromatography, what is the mobile phase?
The solvent
In paper chromatography what does it mean if a spot stays on the pencil line?
The substance is insoluble in that solvent
Why is a pencil used to draw the line in paper chromatography?
Because graphite is insoluble
In paper chromatography what would you change if a spot stays on the pencil line?
The solvent
In paper chromatography, how would you increase the accuracy of the Rf value?
Use a longer piece of paper
What are the 3 stages of making water potable?
- Sedimentation
- Filtration
- Chlorination
Describe simple distillation
- The solution is heated until it boils (it should have anti bumping granules in)
- The solvent vapour evaporates and travels up and along to the condenser
- When the vapour reaches the cold glass it condenses as a distillate
Describe crystallisation
- The solution is heated to evaporate the solvent
- Cool and filter the liquid
- The solute is then left and crystals are formed