Iron

Question 1

When does rusting happen

Answer 1

When iron is in contact with both oxygen and water

Question 2

What is the word equation for rusting

Answer 2

Iron + oxygen + water —> hydrated iron (III) oxide

Question 3

What are the 2 main ways to prevent rusting

Answer 3

1. Barrier Method
2. Sacrificial method

Question 4

What are the 2 types of the barrier method

Answer 4

• Painting/Coating with Plastic - ideal for big and small structures, can be decorative
• Oiling/Greasing - used when moving parting involved e.g. bike chains

Question 5

What is the sacrificial method

Answer 5

Placing a more reactive metal with the iron —> so water and oxygen will react with the sacrificial metal instead of with the iron

Question 6

What metal is normally used as a sacrificial metal and why

Answer 6

Zinc - more reactive than iron, so will be oxidised instead

Question 7

What are the 2 methods that zinc can be applied as a sacrificial metal

Answer 7

• coating of zinc can be sprayed onto object- know as *galvanising
• big blocks of zinc can be bolted to the iron - used on ship’s hulls or underground iron pipes