Mixtures + Chromatogrphy Flashcards
(6 cards)
Define the term ‘mixture’:
Elements/compounds mixed together that are separated using physical methods e.g. chromatography, filtration, crystallizations, fractional distillation, simple distillation
Examples of mixtures?
Air = nitrogen, argon, carbon dioxide + oxygen
Crude oil = different lengths of hydrocarbons
How are properties of the original elements/compounds changed when it becomes a mixture?
Stays the same both chemical + physical
What is chromatography?
The separation of substances to find out what it’s made of
In which situations is chromatography used?
Test for unknown substances at crime scenes + for PEDs during professional sport events.
How do you conduct the chromatography practical?
1 - draw a line around the bottom of the filter paper using a pencil (insoluble)
2 - add a spot of ink on the line
3 - put a solvent in a beaker = ethanol/water (dissolve different things)
4 - lower the paper, don’t touch solvent
5 - place lid on top = prevents evaporation
6 - solvents seeps up paper taking dye with it (solvent front = how far water goes up paper)
7 - dyes travel up at different rates so it’s separates
8 - insoluble = stays at baseline
9 - when the solvent has nearly reached the top of the paper take it out
10 - end result = chromatography