Chapter 9 - Redox

Question 1

Why is iron used in bridges and structures ?

Answer 1

due to it’s strength

Question 2

What is oxidation ?

Answer 2

• gain of oxygen
• loss of hydrogen
• loss of electrons

Question 3

What is reduction ?

Answer 3

• loss of oxygen
• gain of hydrogen
• gain of electrons

Question 4

What is rusting ?

Answer 4

hydrated iron(iii) oxide

Question 5

is rusting an oxidation or reduction reaction ?

Answer 5

gains oxygen so it’s an oxidation

Question 6

recall the three conditions to test rusting experimentally

Answer 6

1 : place in test tube with air and water
2 : place nail in test tube with water and oil on top of water
3: suspend nail and add anhydrous calcium chloride

Question 7

What are the results in the three test tubes

Answer 7

1 : ( water and air) rusting

2: (Water with oil(no air)) no rust
3: (calcium chloride(no water)) no rust

Question 8

Name five ways to prevent rusting

Answer 8

1 - painting
2 - oiling
3 - plastic coating
4 - metal covering/ plating
5 - sacrificial metal (place a metal more reactive on the iron and it will corrode instead of the iron)

Question 9

What is the reducing agent in the extraction of haematite and how is it produced ?

Answer 9

carbon monoxide

hot air is blasted into the furnace and reacts with the coke to produce CO2. The high temp allows the CO2 to react and form CO

Question 10

How is the haematite reduced ?

Answer 10

The CO removes the oxygen from it, producing iron and CO2

Question 11

How are the acidic impurities removed from the haematite ?

Answer 11

Limestone is added to remove them. Then the limestone thermally decomposes to give calcium oxide and carbon dioxide