Substances mixtures and separating

Question 1

Whats a pure substance

Answer 1

A single compound or element

Question 2

Traits of pure substances

Answer 2

Specific boiling and melting point, not over several temps

Question 3

Trait of impure substances

Answer 3

Boil/ met over several temps

Question 4

Whats a formulation

Answer 4

A complex mixture that is specifiically designed
Carefully measured

Question 5

Examples of formulation

Answer 5

Paint, medicine, food, alloys

Question 6

What is filtration

Answer 6

Separating an insoluable liquid and a solid

Question 7

Explain filtration

Answer 7

beaker, funnel and filter paper in funnel
pour the solution into the funnel and the liquid will go through the filter paper, however the solid will be separated.

Question 8

Whats crystalisiation

Answer 8

Separating a soluable solid from a liquid

Question 9

Explain crystalisation

Answer 9

Leave the solution in a beaker for a few days and the liquid will evapourate leaving now solid crystals.

Question 10

Speeding up crystalisation and cons

Answer 10

You can heat it to evapourate faster but heat may effect the chemical so be weary eg. break them down

Question 11

What is distilation

Answer 11

Separating a solid and keeping the liquid

Question 12

Explain distilation

Answer 12

So the mixture is in a flask that is heated until the liquid begins to evapourate, it travels into a condenser where it is condensed back into a liquid as it goes into a beaker.

Question 13

Use of distilation

Answer 13

Can be used for turning sea water into drinking but takes a lot of reasources so probs not.

Question 14

What is frac distilation

Answer 14

Separating two liquids and dif boiling temp

Question 15

Explain frac distilation

Answer 15

Same setup as normal distilation except their are cold beads in the tube above the flask. Heat the solution and both liquids rise however the one with the lower boiling point rises faster, as they meet the beads they condense and rise again until eventually they reach the thermometer. As they go through the condenser theres more of the lower boiling point but its still a mixture untl the thermometer hits the low boiling points temp and will then produce a pure mixture to be collected ina new beaker, as the temp begins to rise again it will stop at the second ones boiling point and the liquid will be purely number two and so on.

Question 16

Negatives of fractional dist

Answer 16

If the liquids have a similar boiling point you may have to do it several times to separate it
it doesnt work for large amounts of liquid eg crude oil

Question 17

what is paper chromatography

Answer 17

separating substances from their solubilites

Question 18

explain chromatography

Answer 18

draw a pencil line near the bottom of chromatography paper and draw however many ink dots on the line, then hold the bottom of it in a solvent.Solvent travels up the paper as does the ink. If there is one spot of colour its pure, several shows a mixure.

Question 19

Stationary phase?

Answer 19

The paper as it doesnt move, the amount the ink travels depends on how attached they are to the paper.

Question 20

effect of changing the solvent in chromatorgraphy

Answer 20

The pure substance may change how far it moves but will always produce the same dot. Mixtures may go into different dots based on the solvent.

Question 21

what is rf value

Answer 21

distance moved by substance/ distance moved by solvent