Paper Chromatogtaphy Flashcards
Chromotography
Analytical method used to separate the substances in the mixture. Used to identify substances.
A mobile phase
Moves through the stationary phase, carrying components of the mixture under investigation. This is always a liquid or a gas(solvent, water or ethanol)
A stationary phase
Where the molecules cannot move. This can be solid or thick liquid(chromatography paper)
Rf value
Rf=distance travelled by substance/distance travelled by solvent
Pure element
Contains only one substance, with no other substances mixed in.
Mixture
Is made up of two or more elements or compounds which are not chemically combined together.
Compounds properties
- fixed composition(the ratio of elements presented)
- need a chemical reaction to separate
- chemical bonds between atoms of different elements
Mixtures properties
- no fixed composition
- can be separated without chemical reaction
- no chemical bonds between atoms
How to separate mixture?
- filtration
- crystalisation
- distillation
- chromotography
Filtration
Used to separate substances that are insoluble in a particular solvent from those that are soluble.
Crystallisation
Used separate soluble solid from a solvent by evaporating the water.
Distillation
Separation of a liquid from a mixture by evaporation followed by condensation.
Uses of distillation
-to obtain freshwater from saltwater
-
Miscible liquids
Liquids that are dissolved in each other.
Immiscible liquids
Form separate layers when mixed.
