C6

Question 1

Which metals are extracted using electrolysis and why?

Answer 1

Potassium, sodium, calcium, magnesium and aluminium because they are higher than carbon in the reactivity series.

Question 2

What are elements that are less reactive than carbon extracted by?

Answer 2

Reduction by carbon because carbon is cheap and abundant.

Question 3

How does reduction by carbon work?

Answer 3

The metal oxide loses its oxygen to form a pure metal. This involves heating the metal oxide with carbon in the form of coal.

Question 4

What is electrolysis?

Answer 4

A process used to extract reactive metals from their molten ores.

Question 5

What is the anode?

Answer 5

It is a positive electrode that is made from carbon because it’s a good conductor and it’s cheap. Carbon dioxide is formed at the anode.

Question 6

What is cathode?

Answer 6

A negative electrode where aluminium is formed.

Question 7

What is a disadvantage of electrolysis?

Answer 7

A lot of energy is needed to melt the solid and produce electrical current which is expensive.

Question 8

What are cations?

Answer 8

Positively charged ions that move towards the cathode.

Question 9

What are anions?

Answer 9

Negatively charged ions that move toward the anode.

Question 10

Do metals go to the cathode or anode and why?

Answer 10

Metals go to the cathode because they form positively charged metal ions because opposites attract.

Question 11

Do non- metals go to the cathode or anode?

Answer 11

Non-metals go to the anode because they form negatively charged non- metals which are attracted to the non- metals ions.

Question 12

What happens to cations during electrolysis?

Answer 12

They gain electrons at the cathode.

Question 13

What happens to anions during electrolysis?

Answer 13

They lose electrons at the positively charged anode.

Question 14

What is the balanced symbol equation for the reaction of copper(II) oxide with carbon?

Answer 14

2CuO +C arrow 2Cu + CO(2)

Question 15

If it says in terms of oxygen..

Answer 15

You say if they gained or lost oxygen.

Question 16

Why is gold easy to extract?

Answer 16

It is found as a pure metal so no extraction process is needed.

Question 17

Why was sodium hard to extract a long time ago?

Answer 17

Sodium is very reactive so was found in compounds so the technology needed to extract it wasn’t available.

Question 18

What is an ore?

Answer 18

A natural rock that contains valuable minerals that can be extracted because its economically worthwhile.

Question 19

What elements do you not use electrolysis or reduction for?

Answer 19

Gold, silver and platinum

Question 20

What’s a disadvantage of reduction by carbon?

Answer 20

It doesn’t purify the metal.

Question 21

How do you heat a blast furnace?

Answer 21

Hot air reacts with the coke (carbon) to produce carbon dioxide and heat energy to heat up the furnace.

More coke is added to the furnace which turns the carbon dioxide in carbon monoxide. In this reaction, iron oxide is reduced to iron and the carbon is oxidised to carbon dioxide.

Question 22

What is the symbol equation for heating a blast furnace?

Answer 22

CO2(g) + C(s) ——> 2CO(g)

2Fe(2)O(3)+ 3C(s) ——> 4Fe+3CO(2)(g)

Question 23

What is the role of cryolite in electrolysis?

Answer 23

Reduces melting point of aluminium oxide
Reduce energy requirements
Make the process cheaper to produce aluminium

Question 24

The anode is made of graphite, why does it have to be replaced often?

Answer 24

Graphite reacts with the oxygen and the anode is burnt away of is oxidised.

Question 25

Why is copper extracted from ores containing a low concentration of copper compounds?

Answer 25

Copper ores are harder to find
They are in demand
They are expensive

Question 26

Why is the extraction of pure copper expensive?

Answer 26

Large amounts of energy is used, the extraction has many steps and the material has to be mined.

Question 27

What in phytomining is to remove metal compounds?

Answer 27

Plants

Question 28

What is phytomining?

Answer 28

When you grow plants in soil that contain metal compounds and the plants can’t use or get rid of the metals so they gradually build up in leaves. The leaves can then be burned in a furnace where the ashes contain metal compounds from which the metal can be extracted by electrolysis.

Question 29

What is bioleaching?

Answer 29

It uses bacteria to separate metals from their ores. The bacteria gets energy between the bonds in the atoms in the ore separating the metal from the ore in the process. The leachate contains metal ions which can be extracted.

Question 30

Why is scrap iron used to displace copper?

Answer 30

Iron is more reactive and cheaper.