separating methods Flashcards
element
substance made up of one type of atom but same number of protons
compound
a substance made of two or more elements which are chemically reacted together
mixture
consists of two or more element/compounds and are not chemically combined
What are pure substances?
(3 marks)
-element made up of one type of atom
-element not mixed with any substances
-they melt and boil at specific temperatures
how to detect whether a substance is pure or impure?
-melt/boil a substance and measure the temperature it melts/boils at
-if it doesn’t melt at a specific temperature, it’s impure
simple distillation
when you separate liquid and a soluble solid
-the solution is heated and pure water evaporates producing a vapour which rises through the neck of the flask and passes through the condenser and condenses
-Turns into a pure liquid which ends up in a beaker. The solute is left behind
heating-evaporation-cooling-condensing
Fractional distillation
Used to separate two or more liquids
-Solution is heated to the temperature of the substance with the lowest boiling point
-Substance evaporates then cools and condenses through a condenser where it is collected into a beaker
-The solution is heated to the boiling temperature of the next substance and this substance evaporates then cools and condenses through the condenser and into the beaker
Filtration
-Separating undisolved solid from a mixture of the solid and liquid solution
Method:
1. a piece of funnel is placed into a filter funnel on top of a beaker
2. the mixture of the insoluble solid and the liquid is passed through the filter funnel
3. Filter funnel only allows liquid molecules to pass the filtrate
4. Solid particles are too large so they stay behind as residue
Paper chromatography
-Separates mixtures and identify substances
1. The further the substance travels up the paper, the more soluble it is
2.The solvent travels up the paper through capillary action and takes some of the substances with it
What you can learn from chromatography
-Different substances have different solubilities (travel at different rates)
-If two or more substances are the same, they will produce identical chromatograms
-If the substance is a mixture, then it will separate all over the paper showing different components as separate spots.
-If the substance is impure,it will show with more than one spot and pure substances show up with only one spot
What you can learn from chromatography:
-Different substances have different solubility rates and travel at different rates
-If two or more substances are the same, they will produce identical chromatograms
-If the substance is a mixture then it will separate all over the paper showing different components as different spots
-If substance is impure, it will show with more than one spot and pure substances show up with only one spot
What you can learn from chromatography:
-Different substances have different solubility rates and travel at different rates
-If two or more substances are the same, they will produce identical chromatograms
-If the substance is a mixture then it will separate all over the paper showing different components as different spots
-If substance is impure, it will show with more than one spot and pure substances show up with only one spot
What you can learn from chromatography:
-Different substances have different solubility rates and travel at different rates
-If two or more substances are the same, they will produce identical chromatograms
-If the substance is a mixture then it will separate all over the paper showing different components as different spots
-If substance is impure, it will show with more than one spot and pure substances show up with only one spot
RF value
-Each substance has its own RF value
-the closer it is to 1, the more soluble it is
RF value equation
distance travelled by the component/distance travelled by solvent
