Chapter 18 Separation techniques

Question 1

Pure products

Answer 1

Only contains the particles shown in its formula

Question 2

Solvent

Answer 2

A substance that dissolves the solute

Question 3

Solute

Answer 3

A substance that is dissolved in the solvent

Question 4

Solution

Answer 4

Mixture of one or more solutes dissolved in a solvent.

Question 5

Aqueous solution

Answer 5

When water is the solvent.

Question 6

Solubility of a substance in water

Answer 6

amount of the solute that dissolves in 100g of water at 25 degrees Celsius

Question 7

Saturated solution

Answer 7

When no more solute can be dissolved in the solution at that temperature

Question 8

Relationship between temperature and solubility

Answer 8

As temperature increases, the solubility of a substance also increases.

Question 9

What are the separationmethods used to separate a solid from a liquid

Answer 9

Filtration
Crystallization

Evaporation (removes solvent completely)

Question 10

How do you separate two solids

Answer 10

find a solvent that dissolves only one of them

Question 11

What is simple distillation

Answer 11

Separate solvent from a solution
Boiling then condensing the solvent

Question 12

Fractional distillation

Answer 12

Separate liquids from each other
Use the difference in boiling points

Question 13

Uses of paper chromatography

Answer 13

Separate substances from a mixture
Check if a substance is pure
Identify substances

Question 14

How does the solvent go up the chromatogram

Answer 14

Capillary action

Question 15

Why do substances travel at different speeds

Answer 15

Depends on the attraction of the substance to the paper and the solvent

The more soluble the substance is in a solvent, the faster it will travel, therefore travelling further

Question 16

Rf value

Answer 16

retention factor

Question 17

Rf formula

Answer 17

Distance from the origin to dot/Distance from origin to solvent front

Question 18

What happens to melting and boiling point of a substance if it is impure

Answer 18

Melting point falls
Boiling point rises

Question 19

What is filteration

Answer 19

A separation method that is used to separate an insoluble solid from a solution

Question 20

What is crystalisation

Answer 20

A separation method used to obtain a solid from a solution

Question 21

What is evaporation

Answer 21

A separation method used to remove all the solvent in order to obtain a solute.

Question 22

steps of chromatography

Answer 22

1)create sample using pestal and mortar
2)decant liquid to collect sample
3)mark baseline using pencil
4)place sample on chromatography
5)place paper in solvent, baseline shouldn’t be completely dipped in solvent
6)wait for pigment to travel if colours should be known use locating agent (ninhydrant sulfate)

Question 23

steps of distillation

Answer 23

1) sample in round bottom flask
2) connect delivery tube and connect condenser on to delivery tube
3) heat round bottom flask using bunsen burner
4) water will condense through condensation chamber and will form in conical flask

Question 24

steps of titration

Answer 24

1) take acid in buret, alkali in conical flask, add indicator to flask containing aklaki. add drop of acid from the buret
2) keep stirring after putting drop
3) wait for colour change from pink to colourless then salt is formed

Question 25

steps of fillteration

Answer 25

attach filter paper to funnel, put sample through filter paper, solids will get trapped in paper (residue) and water will pass (filtrate)

Question 26

when to use a burette

Answer 26

if the amount needed is in decimal eg 25.0

Question 27

when to use pipette

Answer 27

moving small amounts of liquid or when measuring and dispensing liquid in mL units