Chemistry - Metals and their extractions

Question 1

What is oxidation?

Answer 1

The loss of electron from a substance.
It is also the gain of oxygen by a substance.
Opposite of reduction

Question 2

What is reduction?

Answer 2

Reduction is the gain of electrons by a substance.
It is also the loss of oxygen from a substance.
opposite of oxidation

Question 3

What is a redox reaction?

Answer 3

When oxidation and reduction takes place at the same time in a reaction.

Question 4

What is the function of iron ore in a blast furnace?

Answer 4

A compound that the iron is extracted from

Question 5

What is the function of Coke in a blast furnace?

Answer 5

Used as a fuel
Reacts to create Carbon monoxide

Question 6

What is the function of limestone in a blast furnace?

Answer 6

Helps remove acidic impurities in the iron by reacting with them and forming slag

Question 7

What is the function of air in a blast furnace?

Answer 7

Provides oxygen to let the coke burn and produce heat

Question 8

How is iron oxide reduced in a blast furnace?

Answer 8

1. Hot air (oxygen) reacts with coke (carbon) to produce carbon dioxide and heat.
   2.More coke is added to the furnace and reduces the carbon dioxide into carbon monoxide, a good reducing agent.
   3.iron oxide is reduced to iron.

Question 9

How does limestone remove impurities?

Answer 9

1.The calcium carbonate in the limestone thermally decomposes to create calcium oxide.
2.The calcium oxide reacts with the silica(sand) impurities in the iron ore to produce slag(calcium silicate).

Question 10

Where should a blast furnace site be located?

Answer 10

-near the coast to allow for the import of raw materials.
-near roads and railway lines to allow for products to be taken to where they are needed
-near a town or city, so that workers have somewhere to live close-by
-away from built-up areas, so that the noise and pollution of the site do not affect the local population

Question 11

What properties do transition metals have in common?

Answer 11

-Good conductors
-Malleable
-High melting points

Question 12

What are the colours of transition metals?

Answer 12

Iron(II) Fe2+→ pale green

Iron(III) Fe3+ → brown

Copper(II) Cu2+ → blue

Question 13

What is electrolysis?

Answer 13

The decomposition of a compound using an electric current
Positively-charged ions move to the negative electrode (cathode). They receive electrons and are reduced.
Negatively-charged ions move to the positive electrode (anode). They lose electrons and are oxidised.

Question 14

What happens during electrolysis?

Answer 14

-Positively charged ions move to the negative electrode (cathode). They receive electrons and are reduced (lose oxygen)

-Negatively charged ions move to the positive electrode (anode). They lose electrons and are oxidised (gain oxygen)

-The substance that is broken down is called the electrolyte.

Question 15

What are the products of electrolysis of molten electrolytes?

Answer 15

-The metal is formed at the negative electrode because that is where the positive metal ions are attracted
-The non-metal element is formed at the positive electrode where the negative non-metal ions are attracted

Question 16

How is aluminium extracted?

Answer 16

Electrolysis, but first aluminium oxide is melted in molten cryolite - an aluminium compound with a lower melting point. Reduces energy costs as ions are allowed to move more freely at lower temp.

Question 17

What happens in the electrolysis of water?

Answer 17

Electrolysing water splits the water molecules (H2O) into hydrogen (H2) and oxygen (O).
In an experiment the volume of hydrogen produced is double the volume of oxygen. This confirms that there are twice as many hydrogen atoms as oxygen atoms in water.

Question 18

What are the properties of different types of steels and what elements are they made from?

Answer 18

Mild steel - Carbon and Iron - Easy to bend and pull into wires
Tool steel - Tungsten and iron - Hard and can be heated to high temperatures
Stainless steel - Chromium and iron - Hard and does not rust easily

Question 19

What is electroplating?

Answer 19

The use of electrolysis to coat objects with a thin layer of metal.

Question 20

How does electroplating work?

Answer 20

The negative electrode should be the object to be electroplated.
The positive electrode should be the metal that you want to coat the object with.
The electrolyte should be a solution of the coating metal, such as its metal nitrate or sulfate.

Question 21

How is copper purified by electrolysis?

Answer 21

Pure copper rod is connected to anode(positive), impure copper rod is connected to cathode(negative) and are dipped into copper(II) sulfate solution.
Pure copper rod increases in size, while impure rod has deteriorated.