States of Matter and Mixtures

Question 1

What is the process of solids becoming liquids

Answer 1

Melting

Question 2

What is the process of liquids becoming solids

Answer 2

Freezing

Question 3

What is the process of liquids becoming gases

Answer 3

Boiling

Question 4

What is the process of gas becoming a liquid

Answer 4

Condensing

Question 5

Describe the particle arrangement of a solid (3 points)

Answer 5

1. Strong forces of attraction between particles
2. Contains a regular lattice structure
3. Low energy causes particles to vibrate in position

Question 6

Describe the particle arrangement of a liquid (3 points)

Answer 6

1. Weak forces of attraction
2. Particles are free to move
3. Definite volume but not shape

Question 7

Describe the particle arrangement of a gas

Answer 7

1. Weak forces of attraction
2. Don’t have a definite shape or volume
3. Constantly move with a random motion

Question 8

Define the term ‘chemical changes’

Answer 8

When a new product is formed

Question 9

What is particle model

Answer 9

The simplification of particles depicting them as ‘solid, inelastic spheres’

Question 10

Compare the difference between a pure substance and a mixture

Answer 10

Pure substance = a single element or compound, not mixed with any other
substance
Mixture = consists of 2 or more compounds not chemically combined

Question 11

How do pure substances and mixtures vary when melted/boiled

Answer 11

Pure substances have specific melting/ boiling points while mixtures do not

Question 12

What is simple distillation used for (provide 2 answers)

Answer 12

1. The separation of a liquid and a soluble solid
2. Separation of a pure liquid from a mixture

Question 13

Define the word ‘soluble’

Answer 13

Able to be dissolved

Question 14

Write the steps of fractional distillation

Answer 14

1. Heat the solution until pure water evaporates producing a vapour
2. Vapour passes through the condenser turning into a pure liquid collected in a beaker
3. Once all water is evaporated only the solid solute is left behind

Question 15

What is filtration used for

Answer 15

The separation of an insoluble solid from a liquid

Question 16

State the steps of filtration

Answer 16

1. A piece of filter paper is placed in a funnel above a beaker
2. Mixture of insoluble solid and liquid is poured through
3. Small liquid particles will pass through as filtrate
4. Solid particles stay behind as residue

Question 17

What is crystallisation used for

Answer 17

Separation of a soluble solid from a solution

Question 18

State the steps of crystallisation

Answer 18

1. Solution is heated, solvent evaporates leaving a saturated solution
2. Leave the saturated solution to cool slowly
3. Crystals will begin to grow as solids due to decreasing solubility
4. Rinse with cold water to remove impurities and leave to dry

Question 19

What is chromatography used for

Answer 19

The separation of substances with different solubilities in a solvent

Question 20

State the steps of Chromatography

Answer 20

1. Draw a pencil line on chromatography paper placing spots of the sample on it
2. Lower the paper into solvent container leaving the pencil line above the level
3. Allow solvent to travel up the paper via capillary action

Question 21

Why should the line in the chromatography practical be drawn with pen

Answer 21

Ink may run into the chromatogram along with samples

Question 22

How can you tell the difference between a pure and impure substance based off on a chromatogram

Answer 22

Impure substance = more than 1 spot
Pure substance = 1 spot

Question 23

What does Rf value stand for

Answer 23

Retention factor

Question 24

What does calculating the Rf value help to do

Answer 24

Identify unknown substances

Question 25

What is the equation for Rf values

Answer 25

distance travelled by substance ÷ distance travelled by solvent

Question 26

Where does the Rf value lie

Answer 26

Between 0 and 1

Question 27

What is a stationary phase

Answer 27

contained on the paper and does not move through it

Question 28

What is the mobile phase in chromatography

Answer 28

the solvent that moves through the paper carrying different substances with it

Question 29

What are the two parts of investigating the composition of inks practical

Answer 29

1. Simple distillation 2. Chromatography

Question 30

Investigating Inks: state the steps for simple distillation

Answer 30

1. Add small volume of ink to a flask. Connect the flask to the fractionating column and secure it with a stand, boss and clamp. 2. Attach condenser to the top of the fractionating column, connect it to a cold water tap and sink, and secure it over a beaker. 3. Heat the flask using a Bunsen burner reducing the flame as necessary to achieve gentle simmering. 4. Collect a small sample of the distilled solvent

Question 31

Investigating Inks: state the steps for chromatography

Answer 31

1. draw a pencil line across the chromatography paper, 1-2 cm from the bottom 2. use a pipette or capillary tube to add small spots of each ink to the line on the paper 3. place the paper into a container with a suitable solvent in the bottom 4. allow the solvent to move through the paper 5. allow the chromatogram to dry, then measure the distance travelled by each spot and by the solvent

Question 32

Define the term potable

Answer 32

Safe to drink

Question 33

What are the free methods of creating potable water

Answer 33

1. Filtration 2. Sedimentation 3. Chlorination

Question 34

Describe the process of filtration for potable water

Answer 34

clear water passes through filters that have different pore sizes and are made of different materials

Question 35

Describe the process of sedimentation

Answer 35

large insoluble particles clumped by iron/aluminium sulphate will sink to the bottom of the water

Question 36

Describe the process of chlorination

Answer 36

chlorine gas is put through water to kill microbes

Question 37

How can seawater be made potable via distillation

Answer 37

1. filter the seawater 2. boil it 3. water vapour is cooled and condensed

Question 38

What are 2 negatives of using distillation to curate potable water

Answer 38

1. process is expensive as a lot of energy is required 2. Wastewater produced is toxic due to high concentration of salts

Question 39

Why must water used in analyses be pure

Answer 39

any dissolved salts could react with the substances you are analysing, leaving a false result