Reactions of metals

Question 1

Recite the reactivity series from most to least reactive metal.

Include carbon and hydrogen for reference.

Answer 1

• Potassium
• Sodium
• Lithium
• Calcium
• Magnesium
• Carbon
• Zinc
• Iron
• Hydrogen
• Copper
• Gold

Question 2

State the general word equation for the reaction of a metal with water.

Answer 2

metal + water → metal hydroxide + hydrogen

Question 3

sodium + water →

Answer 3

sodium hydroxide + hydrogen

Question 4

State the general word equation for the reaction between a metal and an acid.

Answer 4

metal + acid → salt + hydrogen

Question 5

Which salt is made when magnesium reacts with hydrochloric acid?

Answer 5

magnesium chloride

Question 6

copper + sulfuric acid →

Answer 6

copper sulfate + hydrogen

Question 7

State the general word equation for the reaction between a metal and oxygen.

Answer 7

metal + oxygen → metal oxide

Question 8

magnesium + oxygen →

Answer 8

magnesium oxide

Question 9

2Mg + O₂ → 2MgO

Why is this reaction described as oxidation?

Answer 9

Because magnesium gains oxygen

Question 10

2CuO(s) + C(s) → 2Cu(l) + CO₂(g)

In this reaction, which element is oxidised?

Answer 10

Carbon

Question 11

2CuO(s) + C(s) → 2Cu(l) + CO₂(g)

In this reaction, which element is reduced?

Answer 11

Copper

Question 12

What is reduction?

Answer 12

The loss of oxygen in a chemical reaction

Question 13

Describe what happens in a displacement reaction.

Answer 13

A more reactive metal displaces a less reactive metal from its compound

Question 14

Magnesium + copper sulfate → magnesium sulfate + copper

What kind of chemical reaction is this?

Answer 14

Displacement

Question 15

iron + copper sulfate →

Answer 15

iron sulfate + copper

Question 16

Why is there no reaction when copper is added to magnesium sulfate?

Answer 16

Because copper is less reactive than magnesium (so copper cannot displace magnesium)

Question 17

Mg(s) + CuSO₄(aq) → MgSO₄(aq) + Cu(s)

What is the half equation for the oxidation of magnesium?

Answer 17

Mg(s) → Mg²⁺(aq) + 2e^-

Question 18

Mg(s) + CuSO₄(aq) → MgSO₄(aq) + Cu(s)

What is the half equation for the reduction of copper?

Answer 18

Cu²⁺(aq) + 2e^- → Cu(s)

Question 19

What is oxidation in terms of electrons?

Answer 19

Oxidation is the loss of electrons

Question 20

What is reduction in terms of electrons?

Answer 20

Reduction is the gain of electrons

Question 21

What is a redox reaction?

Answer 21

When reduction and oxidation take place at the same time.

Question 22

What does OIL RIG stand for?

Answer 22

Oxidation

Is

Loss (of electrons)

Reduction

Is

Gain (of electrons)

Question 23

What is an ore?

Answer 23

A rock containing enough quantities of a mineral for extraction to be possible

Question 24

What is a disadvantage of using electrolysis to extract a metal?

Answer 24

Large amounts of electrical energy are needed, so electrolysis is expensive

Question 25

Which metals can be extracted using carbon?

Answer 25

• Zinc
• Iron
• Copper

Question 26

Describe how copper is extracted from its ore using carbon.

Answer 26

Copper oxide is heated with carbon to form copper and carbon dioxide.

Question 27

Copper oxide + carbon → copper + carbon dioxide

Which element is oxidised and which element is reduced when copper is extracted using carbon?

Answer 27

• Carbon is oxidised
• Copper is reduced

Question 28

Iron(III) oxide is reduced to molten iron when it reacts with carbon.

What is the word equation for this reaction?

Answer 28

iron(III) oxide + carbon → iron + carbon monoxide

Question 29

Why must aluminium be extracted from its compound using electrolysis, not heating with carbon?

Answer 29

Because aluminium is more reactive than carbon (so carbon cannot displace aluminium from its compounds)

Question 30

Why is aluminium more expensive than iron?

Answer 30

Because of the large amounts of electrical energy used in the extraction process (electrolysis).

Question 31

What are two ways that aluminium oxide can be made into an electrolyte?

Answer 31

• It is melted (very expensive)
• Powdered aluminium oxide is dissolved in molten cryolite (less expensive)

Question 32

Why is the electrolysis of aluminium oxide so expensive?

Answer 32

• Aluminium oxide has a very high melting point
• A lot of energy is required to break its ionic bonds

Question 33

What is formed at the cathode during the electrolysis of aluminium oxide? How does this product form?

Answer 33

At the cathode, aluminium ions gain electrons and form aluminium atoms

Question 34

What is formed at the anode in the electrolysis of aluminium oxide? How is this product formed?

Answer 34

At the anode, oxide ions lose electrons and form oxygen gas

Question 35

Oxygen is produced at the anode in the electrolysis of aluminium chloride.

What is the half equation for the reaction at the anode?

Answer 35

2O^2- → O₂ + 4e^-

Question 36

Aluminium is produced at the cathode in the electrolysis of aluminium oxide.

What is the half equation for this reaction?

Answer 36

Al³⁺ + 3e^- → Al