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Question 1

Pure substances have…

Answer 1

Specific melting and boiling points

Question 2

What are formulations?

Answer 2

Mixtures of certain quantities of substance eg paint, fuel, alloys, fertilisers etc.

Question 3

What does paper chromatography do?

Answer 3

It allows us to separate substances based on their different solubilities

Question 4

Chromatography paper set up

Answer 4

Draw line in pencil on the paper (stationary phase)- dot of colour goes on the line. Put the paper in a solvent (mobile phase) under the line (not submerging the dots.

Question 5

What will pure compounds form in paper chromatography

Answer 5

One single spot

Question 6

What will compounds in a mixture form in paper chromatography

Answer 6

Multiple spots

Question 7

Why do you draw the line in pencil?

Answer 7

So that the ink doesn’t also move up the page

Question 8

What is the mobile phase

Answer 8

The solvent (eg water)- moves up by capillary action

Question 9

What is the stationary phase

Answer 9

The chromatography paper

Question 10

What is the solvent front in chromatography

Answer 10

The top of the solvent

Question 11

How to find Rf Values paper chromatography?

Answer 11

distance moved by substance/distance moved by solvent

Question 12

How to test for hydrogen

Answer 12

We insert a burning splint when the hydrogen gas burns and produces a pop sound

Question 13

How to test for oxygen

Answer 13

Glowing splint will relight

Question 14

How to test for carbon dioxide

Answer 14

Bubble through limewater (aqueous calcium hydroxide) and turns cloudy

Question 15

How to test for chlorine

Answer 15

Insert damp blue litmus paper into the test tube, and bleaches it

Question 16

What flame does lithium ion produce

Answer 16

Crimson

Question 17

What flame does sodium ion produce

Answer 17

Yellow

Question 18

What flame does potassium ion produce

Answer 18

Lilac

Question 19

What flame does calcium ion produce

Answer 19

Orange-red

Question 20

What flame does copper ion produce

Answer 20

Green

Question 21

What colour precipitate do calcium, magnesium and aluminium form when combined with sodium hydroxide

Answer 21

White

Question 22

How do you work out which white precipitate is aluminium?

Answer 22

Add an excess of NaOH (the aluminium dissolves and the solution goes clear again)

Question 23

What colour do Cu 2+ ions turn when reacted with sodium hydroxide

Answer 23

Blue- copper (II) hydroxide

Question 24

What colour do Fe 2+ ions turn when reacted with sodium hydroxide

Answer 24

Green- iron (II) hydroxide

Question 25

What colour do Fe 3+ ions turn when reacted with sodium hydroxide

Answer 25

Brown-red- Iron (III) hydroxide

Question 26

How to test for a carbonate ion

Answer 26

Add dilute acid to the sample The acid will react with the carbonate to make CO2 gas Bubble the gas through limewater to make sure that we have carbon dioxide and therefore started with a carbonate ion

Question 27

How to test for halide ions

Answer 27

Add dilute nitric acid Then add dilute silver nitrate solution Halides each produce a precipitate of the silver halide

Question 28

What colour do chloride ions produce?

Answer 28

White- silver chloride

Question 29

What colour precipitate do bromide ions produce?

Answer 29

Cream- silver bromide

Question 30

What colour precipitate do iodide ions produce?

Answer 30

Yellow- silver iodide

Question 31

How to test for sulfate ions

Answer 31

Add dilute HCL to our sample Add barium chloride solution If sulfate ions are present, we will see a white precipitate

Question 32

Flame Emission Spectroscopy

Answer 32

Analysis of the wavelengths of light emitted from a flame, which can be used to identify ions.

Question 33

What is potable water

Answer 33

Water that's safe to drink

Question 34

Criteria for potable water

Answer 34

Level of dissolved substances need to be fairly low pH between 6.5-8.5 No microorganisms in it

Question 35

How to make water potable

Answer 35

Fresh water passed through wire mesh to remove big things Bed of sand and gravel to filter out smaller bits Sterilise by bubbling chlorine gas through/using ozone or UV light

Question 36

How to desalinate water

Answer 36

Use distillation to get pure distilled water Reverse osmosis- pass salty water through a membrane that only lets water molecules through

Question 37

Sources of wastewater

Answer 37

Domestic Agricultural systems Industrial

Question 38

How to treat sewage

Answer 38

Run through mesh to remove large objects 'Sedimentation' allows for sludge to sink to the bottom and the lighter effluent to stay at the top Breakdown organic matter biologically by microorganisms