States Of Matter And Mixtures

Question 1

Solids
Forces
Position
Movement

Answer 1

Strong forces of attraction between particles
Fixed position - regular pattern
Vibrate around a fixed position

Question 2

Liquids 
Forces 
Position
Energy 
Movement

Answer 2

Some forces of attraction between particles
Free to move
Don’t keep to a shape - irregular pattern
More energy than solids
Move around each other

Question 3

Gases 
Forces 
Shape
Energy 
Movement

Answer 3

No forces 
Don’t keep a definite shape 
Exert pressure on walks 
Lots of energy 
Move fast around each - cause collisions

Question 4

Solid to liquid

Answer 4

Melting
When a solid is heated it gains more energy
Makes the particles vibrate more weakens the bonds of the forces

Question 5

Solid to gas

Answer 5

Subliming

Question 6

Liquid to solid

Answer 6

Freezing

Question 7

Liquid to gas

Answer 7

Boiling or evaporating

Question 8

Gas to liquid

Answer 8

Condensing

Question 9

Chemical changes - chemical reactions

Answer 9

Bonds between atoms break
They rearrange to form the products
Chemical changes are harder to reverse then state changes

Question 10

Pure

Answer 10

If a substance is completely made of a single compound or element

Question 11

Pure example

Answer 11

It may be thought as pure however it is chemically impure as it is made up of -
Argon
Nitrogen
Oxygen

Question 12

How to test for a pure substance?

Answer 12

Every pure substance has a specific sharp melting and boiling point
You can test the purity of a substance by comparing its actual melting point to its expected value

Question 13

Measuring the melting point

Answer 13

Use a melting point apparatus
Allows you to heat up a small sample very slowly
So you can observe and record the exact temp

Question 14

Distillation

Answer 14

Used for separating out of a liquid from a solution

Question 15

Cons of simple distillation

Answer 15

Only use it to separate things with very different boiling points

Question 16

Fractional distillation

Answer 16

If you have a mixture of liquids, you can separate it using fractional distillation

Question 17

Filtration

Answer 17

Used to separate on insoluble solid from a liquid

Question 18

Crystallization method

Answer 18

Pour solution into evaporating dish and heat
Once water evaporated or crystals start to form - remove from heat
Salt should start to form crystals -insoluble, cold, highly conc
Filter crystals out of solution

Question 19

Chromatography

Answer 19

A method used to separate a mixture of soluble substances and identify them

Question 20

Mobile phase of chromatography

Answer 20

Where the molecules can move -liquid or gas

Question 21

Stationary phase - chromatography

Answer 21

Where the molecules can’t move - solid or thick liquid

Question 22

How does chromatography work?

Answer 22

The different components in the mixture separate out as mobile phase moves over the stationary phase
- each different chemicals in a mixture will spend different time dissolved in the mobile phase

Question 23

Paper chromatography -mobile and stationary

Answer 23

Stationary - the piece of filter paper

Mobile - solvent

Question 24

Chromatography - method

Answer 24

Draw a line near bottom of paper
Put a spot of mixture on to line
Put solvent in beaker, put paper in solvent
Solvent will move up, so will the mixture when it dissolved into solvent
See the different chemicals separate
Remove paper from beaker

Question 25

The amount of time that each molecule spends in each phase depends on ...

Answer 25

How soluble they are in a solvent | How attracted they are to the stationary phase

Question 26

If molecules have a high solubility ...

Answer 26

They are less attracted to the paper, spend more time in the mobile phase They will go higher up in the mobile phase

Question 27

Rf Value

Answer 27

The ratio between the distance travelled by the dissolved substance and the distance travelled by the solvent

Question 28

Ref value calculation

Answer 28

Distance travelled by solute / distance travelled by solvent

Question 29

What can you use chromatography for? | Certain substance

Answer 29

To see if a certain substance is present Run a pure sample Run sample of the mixture If they have the same Rf value they are the same

Question 30

What can you use chromatography for?

Answer 30

To do a purity test | Pure substances won’t be separated by chromatography

Question 31

Practical - analyse the composition in ink | Simple distillation

Answer 31

Evaporate off the solvent a collect it | Thermometer should tell you the boiling points to try and determine what it is

Question 32

Practical - analyse the composition in ink | Paper chromatography

Answer 32

Separate out the different dyes | Compare the Rf values of the different spots to work out the different dyes

Question 33

Surface water

Answer 33

Lakes, rivers and reservoirs | Start to run dry during summer months

Question 34

Ground water

Answer 34

Aquifers - rocks that trap water underground

Question 35

Waste water

Answer 35

From water that has been contaminated by human process

Question 36

Purification of water- filtration

Answer 36

A wire mesh screens out large twigs | Gravel and sand beds filter out any solid bits

Question 37

Purification of water- sedimentation

Answer 37

Iron sulfate or aluminum sulfate is added to the water- makes the particles clump together and settle at the bottom

Question 38

Purification of water- chlorination

Answer 38

Chlorine gas is bubbles through to kill any harmful bacteria or microbes

Question 39

Potable water from sea water

Answer 39

Sea water is distilled | It needs lots of energy so it’s expensive

Question 40

What water is used in a chemical analysis?

Answer 40

Deionized water - water that has had ions removes | Ions are harmless to drinking but can interfere with reactions