cc2 Flashcards
What is a pure substance
Made up of a single element or compound
What is an element
All atoms are the same
What is a compound
Contains two or more different elements chemically combined in a fixed position
What is a mixture
Different elements or compounds not chemically joined
What is a molecule
Any element chemically joined
What is filtration used for
To separate an insoluble solid from a liquid
What are the steps of filtration
Pour the mixture through the filter paper that is in the funnel.
Then the liquid part will run through whilst leaving behind the solid residue
What is crystillsation used for
To separate a soluble solid from a solution
What are the steps of crystallisation
1) Pour solution into evaporating dish and gently heat.
2) Some of the water will evaporate and solution will get more concentrated
3) Once you see crystals forming you stop heating and leave solution to cool
4) Cooling will lead to more crystals forming as solids are less soluble at colder temperatures
5) Filter out crystals and dry
What is paper chromatography used for
Paper chromatography allows us to separate substances based on their different solubilities
What are the steps of Paper chromatography
1) Draw a line at the bottom of the paper (baseline) in pencil as the pencil is insoluble
2) Add sample of ink
3) Put paper into solvent but do not submerge the ink and put the lid on top
4) The solvent will move up the paper and you will see different dyes forming spots on the paper
5) Remove paper from beaker before solvent reaches the top and mark distance solvent has moved (solvent front)
What is the mobile phase
Molecules can move so its the solvent
What is the stationary phase
Molecules can’t move so its the paper
How do you calculate the RF value
distance travelled by solute/distance travelled by solvent
What is simple distillation used for
Separating a liquid from a solution