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Question 1

What are the 3 states of matter?

Answer 1

Gas
Liquid
Solid

Question 2

What are the properties of a solid?

Answer 2

1. They have strong forces of attraction between particles, which hold them in a fixed positions in a regular lattice arrangement.
2. The particles don’t move from their positions so all solids keep a definite shape and volume.
3. The particles don’t have much energy.
4. They hardly move at all - they can only vibrate about their fixed positions. The hotter the solid becomes, the more they vibrate, (expand slightly).

Question 3

What are the properties of a liquid?

Answer 3

1. There is some force of attraction between the particles. They’re free to move past each other, but they do tend to stick together.
2. They don’t keep a definite shape and will flow to fill the bottom of a container. They do keep the same volume.
3. In liquid state the particles have more energy than in solid state.
4. The particles are constantly moving with random motion. The hotter the liquid gets, the faster they move. (Causes it to expand slightly).

Question 4

What are the properties of a gas?

Answer 4

1. Pretty much no force of attraction between the particles - they’re free to move. They travel in straight lines and only interact when they collide.
2. They don’t keep a definite shape or volume and will always fill any container.
3. In gas state particles have more energy than in solid or liquid state.
4. Particles are constantly moving with random motion. The hotter it gets the faster they move. Gases either expand or their pressure increases when heated.

Question 5

What are the names for the changes of state?

Answer 5

Solid - liquid = melting
Liquid - solid = freezing

Liquid - gas = evaporating
Gas - liquid = condensing

Solid - gas = subliming

Question 6

What do pure substances made of?

Answer 6

Completely made up of a single element or compound.

Question 7

What is a mixture?

Answer 7

When you’ve got more than one compound present, or different elements that aren’t part of a single compound

Question 8

What’s a compound?

Answer 8

Different elements bonded together.

Question 9

What’s an element?

Answer 9

Atoms are identical.

Question 10

How can you test for purity?

Answer 10

Using melting points.

Question 11

How does the test for purity work?

Answer 11

1. Every pure substance has a specific, sharp melting point and boiling point. (E.g - water freezes at 0 and boils at 100).
2. You can use this to test the purity of a sample of a substance, by comparing the actual meting point of the sample to the expected value.

Question 12

What does simple distillation do?

Answer 12

Separating out a liquid from a solution.

Question 13

What’s the method for a simple distillation, when getting pure water from seawater?

Answer 13

1. Pour your sample of seawater into the distillation flask.
2. Set up the apparatus. Connect the bottom end of the condenser to a cold tap using rubber tubing. Run cold water through the condenser to keep it cool.
3. Gradually heat the flask. The part of the solution that has the lowest boiling point will evaporate - in this case the water.
4. The water vapour passes into the condenser where it cools and condenses. It then flows into the beaker where it is collected.
5. Eventually there will be just salt left tin the flask.

Question 14

What’s the problem with simple distillation?

Answer 14

Its that you can only use it to separate things with very different boiling points.

If you have a mixture with similar boiling points, you need another method such as fractional distillation.

Question 15

What does filtration do?

Answer 15

Its used to separate an insoluble solid from a liquid.

Question 16

How do you carry out a filtration?

Answer 16

Put some filter paper into a funnel and pour your mixture into it. The liquid part of the mixture runs through the paper, leaving behind the solid residue.

Question 17

What does crystallisation do?

Answer 17

Separates a soluble liquid from a solution.

Question 18

How do you carry out crystallisation?

Answer 18

1. Pour the solution into an evaporating dish and gently heat the solution. Some of the water will evaporate and the solution will get more concentrated.
2. Once some of the water has evaporated, or when you see crystals start to form, remove the dish form the heat and leave the solution to cool.
3. The salt should start to form crystals as it becomes insoluble in the cold, highly concentrated solution.
4. Filter the crystals out of the solution, and leave them in a warm place to dry.

Question 19

What is chromatography?

Answer 19

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

Question 20

What are the two phases of chromatography?

Answer 20

Mobile phase.

Stationary phase.

Question 21

What is the mobile phase?

Answer 21

Where the molecules can move. This is always a liquid or gas.

Question 22

What is the stationary phase?

Answer 22

Where the molecules cant move. This can be a solid or a really thick liquid.

Question 23

What is the method for paper chromatography?

Answer 23

1. Draw a line near the bottom of the paper. (Use pencil as its insoluble).
2. Put a small spot of ink form each pen on your line.
3. Pour some water into the beaker to a depth of about 1cm, and lower the chromatography paper into the beaker so that the bottom of the paper is int he water but the water isn’t touching the ink.
4. Leave the paper in the beaker until the water reaches near the top of the paper.
5. Take the paper out and immediately use a pencil to mark the location of the solvent front before it evaporates. Leave it to dry.

Question 24

What is the baseline?

Answer 24

The line near the bottom of the paper.

Question 25

What is the solvent front?

Answer 25

The distance the solvent has moved.

Question 26

What is a solute?

Answer 26

A substance that gets dissolved.

Question 27

What is a solvent?

Answer 27

It’s a liquid able to dissolve other substances

Question 28

What’s a solution?

Answer 28

A mixture of a solute and solvent.

Question 29

What is a chromatogram?

Answer 29

In paper chromatography, its the piece of paper that you end up with.

Question 30

What’s the equation for the Rf values?

Answer 30

Rf = distance travelled by solute / distance travelled by solvent.

Question 31

How do you find the distance travelled by the solute?

Answer 31

Measure from the baseline to the centre of the spot.

Question 32

Where do we get our water from?

Answer 32

Surface water
Ground water
Waste water

Question 33

What is surface water?

Answer 33

From lakes, rivers and reservoirs.

In much of England and Wales, these sources start to run dry during the summer months.

Question 34

What is ground water?

Answer 34

From aquifers (rocks that trap water underground).

In south-east England, where surface water is limited, as much as 70% of domestic water supply comes from ground water.

Question 35

What is waste water?

Answer 35

From water that’s been contaminated by a human process.

Treating waste water to make it potable is preferable to disposing of it, which can be polluting.

Question 36

How is water purified?

Answer 36

Filtration
Sedimentation
Chlorination

Question 37

What does filtration do?

Answer 37

A wire mesh screens out large twigs etc… and then gravel and sand beds filter out any other solid bits.

Question 38

What does sedimentation do?

Answer 38

Iron sulfate or aluminium sulfate is added to the water, which makes fine particles clump together and settle at the bottom.

Question 39

What does chlorination do?

Answer 39

Chlorine gas is bubbled through to kill harmful bacteria and other microbes.

Question 40

What is potable water?

Answer 40

Drinking water

Question 41

How can you get water in very dry countries?

Answer 41

Distilling sea water to produce drinking water.

However it needs lots of energy, so it really expensive, especially is you’re trying to produce large quantities of fresh water.