Corrosion

Question 1

Corrosion

Answer 1

reaction of metal with substances in its surrounding such as air or water

Question 2

How does iron rust?

Answer 2

if iron comes into contact with air and water after a while it will rust
only happens if iron is in contact with both oxygen (from air) and water

Question 3

Rust is a form of…

Answer 3

hydrated iron (III) oxide

Question 4

Equation showing formation of rust

Answer 4

iron + oxygen -> hydrated iron(III) oxide

Question 5

Explain how iron rusting is a redox reaction

Answer 5

iron loses electrons when its reacts with oxygen
each Fe atom loses 3 electrons to become Fe3+
so iron is oxidised
simultaneously oxygen gains electrons when it reacts with iron
each O atom gains 2 electrons to become O2-
so oxygen is reduced

Question 6

How can you prevent corrosion?

Answer 6

coating the metal with a barrier to keep out the water, oxygen or both

paint is ideal for large or small structures
oil and grease has to be used for moving parts such as bike chains

Question 7

What will stop steel from corroding?

Answer 7

Tin - acts as a barrier stopping water and oxygen in the air from reaching metals surface
only works if tin coating remains intact

Question 8

What is a sacrificial method?

Answer 8

Placing a more reactive metal on whatever you don’t want to corrode
water and oxygen hen reacts with this ‘sacrificial’ metal instead of the metal you’re protecting

Question 9

Galvanising

Answer 9

coat of zinc ism put onto an iron object to prevent rusting
zinc acts as a sacrificial protection
it is more reactive than iron so it’ll loose electrons in preference to iron
zinc also acts as a barrier