separation techniques

Question 1

mobile phase

Answer 1

a gas or liquid where the molecules are able to move

Question 2

stationary phase

Answer 2

a solid or thick liquid where the molecules are unable to move

Question 3

solute

Answer 3

a substance dissolved in a solvent to make a solution

Question 4

solvent

Answer 4

a liquid in which a solute can be dissolved

Question 5

solution

Answer 5

a mixture mad up of one substance dissolved in another

Question 6

why should you use pencil in chromatography?

Answer 6

it is insoluble and won’t dissolve in the solvent and affect the results

Question 7

filtration

Answer 7

used to separate an insoluble solid from a liquid

Question 8

chromatography

Answer 8

used to separate the substances in a mixture based on how the components interact with a mobile and stationary phase

Question 9

what is crystallisation?

Answer 9

the formation of solid crystals as water evaporates from a solution

Question 10

insoluble

Answer 10

the solid can’t be dissolved in the liquid

Question 11

crystallisation process

Answer 11

1. pour solution into an evaporating dish and gently heat
2. once some of the solvent has evaporated or you see crystals start to form, remove the dish from the heat and leave it solution to cool
3. salt should start to form crystals as it becomes insoluble
4. filter the crystals out of the solutions and leave them in a warm place to dry

Question 12

evaporation process

Answer 12

1. pour the solution into an evaporating dish
2. slowly heat the solution
3. keep heating until all you have left are dry crystals

Question 13

when do you have to use crystallisation?

Answer 13

if the salt decomposes when its heated

Question 14

simple distillation

Answer 14

used for separating a liquid from a solution

Question 15

simple distillation process

Answer 15

1. solution is heated, lowest boiling point evaporates first
2. vapour is then cooled, condenses and is collected
3. rest of the solution left behind in the flask

Question 16

issue with simple distillation

Answer 16

can only separate things with very different boiling points as if the temp goes higher than the boiling point of the highest substance, they will mix again

Question 17

fractional distillation process

Answer 17

1. heat the mixture
2. the liquid with the lowest boiling point will evaporate first, it will reach the top of the column
3. liquids with higher boiling points might also start to evaporate but the column is cooler at the top so they will condense and run back down
4. when the first liquid has been collected, you raise the temperature for the next one

Question 18

filtration process and why

Answer 18

1. filter to remove insoluble solids
2. filter paper placed in funnel over beaker/flask
3. pour mixture through funnel
4. insoluble product left on filter paper, liquid collected in beaker

Question 19

what method should be used to separate a soluble solid from a solution if it decomposes when heated?

Answer 19

crystallisation

Question 20

soluble

Answer 20

can be dissolved

Question 21

insoluble

Answer 21

can’t be dissolved