Iron 4.43

Question 1

When does Iron rust

Answer 1

when it is in contact with oxygen and water

Question 2

What kind of reaction takes place when iron rusts

Answer 2

oxidation

Question 3

What happens to iron when it rusts

Answer 3

Water becomes loosely bounded to the iron leading to hydrated iron(III) oxide

Question 4

What is the word equation for when iron rusts

Answer 4

iron + oxygen = water — hydrated iron(III) oxide (rust)

Question 5

What is one method of preventing rust that involves coating the iron

Answer 5

Barrier methods:
Painting/coating with plastic- can be decorative
Oiling and greasing- for moving parts like chains

Question 6

What is one method of preventing rust that involves using a more reactive metal than iron

Answer 6

Sacrificial method:

Water and oxygen react with the more reactive metal before reaching the iron

Question 7

Name one sacrificial method

Answer 7

Zinc is further up in the reactivity series
Zinc is oxidised instead of iron
Coating of zinc sprayed on the object- galvanising
Or big blocks of zinc can be bolted onto the iron-
used on ships’ on hulls, or on underground pipes