2 - Distillation & Filtration Flashcards
What is simple distillation?
Separating a liquid from a solution
How is simple distillation used to get pure water from sea water?
- Pour seawater into distillation flask
- Set up experiment - connect bottom end of condenser to a cold tab w/rubber tubing. Run cold water through condenser to keep it cool
- Gradually heat flask, evaporate the part of solution that has the lowest boiling point (water)
- Water vapour passes into condenser & turns to liquid collected in beaker
- End up with just salt in the flask
What is required for simple distillation to work?
Two things with very different boiling points - if they have similar boiling points it won’t work
What is fractional distillation?
Separating a mixture of liquids even if their boiling points are close together
How is fractional distillation used to separate crude oil?
- Put mixture in flask
- Attach a fractionating column & condenser above flask
- Gradually heat flask - liquids all have diff boiling points so will evaporate at diff temps
- Lowest boling point evaporates first & will reach the top of column
- Higher boiling points may start to evaporate but as it’s cooler by the top they will cool & go back down
- Once first liquid is collected, raise temp & move on/repeat
What is Filtration?
Separating an Insoluble solid from a liquid
How do you Filtration?
. Put filter paper into a funnel & pour mixture into it
. Liquid part of mixture runs through the paper, leaving behind a solid residue
What can Filtration also be used for?
Purification
eg. solid impurities can be separated from a mixture using filtration
What is Crystallisation?
Separating a soluble solid from a solution
How do you Crystallise a product?
- Pour solution into evaporating dish & gently heat ; some water will evaporate & solution will get more concentrated
- Once some water evaporated/crystals start to form, remove dish from heat & cool
- Salt should form crystals as it becomes insoluble
- Filter crystals out & leave to dry
