C4

Question 1

What is made when a metal reacts with oxygen?

Answer 1

Metal oxide

Question 2

What type of reaction is magnesium and oxygen

Answer 2

Quick and vigorous reaction

Question 3

What is it called when oxygen is gained in a reaction?

Answer 3

Oxidation

Question 4

Give an example of an reduction reaction

Answer 4

Magnesium oxide —- magnesium + oxidation
- the magnesium has lost oxygen

Question 5

What is a reduction reaction?

Answer 5

When oxygen is lost during the reaction

Question 6

In this equation,

calcium +copper oxide —> calcium oxide + copper

What has been oxidised and reduced?
Why does this happen?

Answer 6

• Calcium has been oxidised and the copper has been reduced
• It happens because calcium is more reactive than copper so it displaces it

Question 7

How does potassium, sodium and lithium react with acids?

Answer 7

Dangerously fast reaction with acids

Question 8

How does copper react with acid?

Answer 8

No reaction as copper is so unreactive

Question 9

What happens when metals react?

Answer 9

They lose electrons and form a positive ion

Question 10

What does the reactivity of a metal depend on?

Answer 10

Its ability to lose electrons and form a positive ion

Question 11

In aqueous solutions acids produce what?

Answer 11

Hydrogen ions - H*

Question 12

What are bases?

Answer 12

• Chemicals which can neutralise acids producing a salt and water
• usually metal oxides or metal hydroxides
• based which are soluble in water are called alkalies

Question 13

In aqueous solutions what do alkalies produce?

Answer 13

Hydroxide ions (OH-)

Question 14

How can we determine the pH of a solution?

Answer 14

• Ph probe (electronically)
• universal indicator

Question 15

All acids contain what?

Answer 15

Hydrogen

Question 16

When magnesium react they lose how many electrons?

Answer 16

2

Question 17

Gaining electrons in a reaction is another word for what?

Answer 17

Reduction

Question 18

When we react an acid with either a base or an acid we get what?

Answer 18

Salt and water

Question 19

When metals react with a metal carbonate what do they make?

Answer 19

Salt, water and carbon dioxide

Question 20

Strong acids do what in aqueous solutions?

Answer 20

Fully ionise

Question 21

Examples of strong acids?

Answer 21

• Hydrochloric acid
• sulphuric acid
• nitric acid

Question 22

Examples of weak acids…

Answer 22

• Carbonic acid
• ethnanoic acid
• citric acid

Question 23

What does the concentration of an acid tell us?

Answer 23

The amount of acid molecules in a given volume of solution

Question 24

Why can’t solid components conduct electricity?

Answer 24

Because the ions are locked in place they are not free to move. Held together by strong electrostatic forces of attraction

Question 25

Why can solid compounds conduct electricity when melted or dissolved in water?

Answer 25

The forces of attraction are broken and the ions are free to move

Question 26

In electrolysis what is the negative electrode called?

Answer 26

Cathode

Question 27

What is the positive electrode in electrolysis called?

Answer 27

Anode (lack of electrons)

Question 28

Why do we mix cryolite in the electrolysis of aluminium oxide?

Answer 28

Because aluminium oxide has a very high melting point and requires a lot of energy to melt. By adding cryolite we lower the melting point, reducing the amount of energy needed and saves money

Question 29

Why is the cathode and anode made of graphite (carbon)?

Answer 29

• good conductor
• High melting point

Question 30

Why do we replace the anode regularly?

Answer 30

Because the oxygen molecules produced at the anode react with graphite to form carbon dioxide gas

Question 31

When does hydrogen get produced at the cathode?

Answer 31

If the metal is more reactive than hydrogen

Question 32

If the aqueous solution contains a halide ion what will be produced at the anode?

Answer 32

The halogen