C8 - Chemical analysis

Question 1

What is the test for hydrogen?

Answer 1

A lit splint makes a squeaky pop.

Question 2

What is the test for oxygen?

Answer 2

A glowing splint relights.

Question 3

What is the test for carbon dioxide?

Answer 3

Limewater turns cloudy (calcium carbonate forms) once the gas is bubbled through.

Question 4

What is the test for chlorine gas?

Answer 4

Damp blue litmus paper is bleached.

Question 5

Which test can be used to test for lithium ions?

Answer 5

A crimson flame from a flame test.

Question 6

Which test can be used to test for sodium ions?

Answer 6

A yellow flame from a flame test.

Question 7

Which test can be used to test for potassium ions?

Answer 7

A lilac flame from a flame test.

Question 8

Which two tests can be used to test for calcium ions?

Answer 8

• An orange-red flame from a flame test
• A white precipitate when sodium hydroxide solution is added

Question 9

Which two tests can be used to test for copper II ions?

Answer 9

• A green flame from a flame test
• A blue precipitate when sodium hydroxide solution is added

Question 10

Which test can be used to test for iron II ions?

Answer 10

A green precipitate when sodium hydroxide solution is added.

Question 11

Which test can be used to test for iron III ions?

Answer 11

A brown precipitate when sodium hydroxide solution is added.

Question 12

Which test can be used to test for magnesium ions?

Answer 12

A white precipitate when sodium hydroxide solution is added.

Question 13

Which test can be used to test for aluminium ions?

Answer 13

A white precipitate when sodium hydroxide solution is added. This will dissolve once sodium hydroxide solution is in excess.

Question 14

Which test can be used to test for chloride ions?

Answer 14

A white precipitate when nitric acid then silver nitrate are added.

Question 15

Which test can be used to test for bromide ions?

Answer 15

A cream precipitate when hydrochloric/nitric acid then silver nitrate are added.

Question 16

Which test can be used to test for iodide ions?

Answer 16

A yellow precipitate when hydrochloric/nitric acid then silver nitrate are added.

Question 17

Which test can be used to test for carbonate ions?

Answer 17

A fizz when added to acid AND limewater turning cloudy when bubbled through.

Question 18

Which test can be used to test for sulfate ions?

Answer 18

A white precipitate when hydrochloric acid then barium chloride are added.

Question 19

Define purity in terms of chemistry.

Answer 19

A substance that is made up of just one substance. That substance can be either an element or a compound.

Question 20

Define purity in terms of advertising.

Answer 20

A substance ‘has had nothing added to it’ and that it is in its natural state.

Question 21

Define purity in terms of advertising.

Answer 21

A substance ‘has had nothing added to it’ and that it is in its natural state.

Question 22

What do impurities do to the boiling and melting points of a substance?

Answer 22

Decrease them.

Question 23

What is a formulation?

Answer 23

A mixture that has been designed to produce a useful product.

Question 24

What is the stationary phase in chromatography?

Answer 24

The paper.

Question 25

What is the mobile phase in chromatography?

Answer 25

The solvent.

Question 26

How is the Rf value calculated?

Answer 26

distance moved by chemical ÷ distance moved by solvent