iron, steel and other metals

Question 1

what is rusting?

Answer 1

a chemical process by which iron is oxidised to form rust

Question 2

what is the chemical name for rust?

Answer 2

hydrated iron (III) oxide

Question 3

properties of iron?

Answer 3

-grey
-solid
-malleable

Question 4

properties of hydrated iron (III) oxide?

Answer 4

-brown
-dull
-brittle

Question 5

what does rusting require?

Answer 5

oxygen and water

Question 6

iron is oxidised or reduced to form iron (III oxide)?

Answer 6

oxidised by oxygen

Question 7

iron (III) oxide becomes hydrated by what?

Answer 7

water

Question 8

what 2 methods can rusting be prevented?

Answer 8

• using a barrier
• sacrificial protection

Question 9

what is using a barrier?

Answer 9

coating the iron in paint, oil, grease or plastic

Question 10

how does using a barrier prevent rusting from occuring?

Answer 10

prevents the iron from coming into contact with oxygen or water

Question 11

when does using a barrier work?

Answer 11

as long as the coating is intact- as soon as it breaks, rusting occurs

Question 12

what is sacrificial protection?

Answer 12

attach a block of more reactive metal (e.g magnesium) to the iron

Question 13

how does sacrificial protection work?

Answer 13

it displaces the iron from the rust as soon as the rust forms

Question 14

what is a con of sacrificial protection?

Answer 14

the block of magnesium has to be replaced often

Question 15

what is galvanising?

Answer 15

coating the iron in zinc

Question 16

how does galvanising work?

Answer 16

• the coating prevents O2 and H2O from coming into contact with the iron
• if there is a crack in the coating, zinc is more reactive than iron so it acts as sacrificial protection as well

Question 17

what is an alloy?

Answer 17

mixtures of metals with one or more other elements

Question 18

steel is made up of what elements?

Answer 18

iron and carbon

Question 19

brass is made up of what elements?

Answer 19

copper and zinc

Question 20

bronze is made up of what elements?

Answer 20

copper and tin

Question 21

why are alloys harder than pure metals?

Answer 21

• the different sized atoms/ ions prevent the layers of metal ions from sliding over eachother
• this means the alloy is less malleable

Question 22

why do we use iron to make steel?

Answer 22

steel is more useful than iron

Question 23

what is the use of low- carbon steel?

Answer 23

ships, cars, bridges etc

Question 24

what is the reason for using low- carbon steel?

Answer 24

-strong
-can be hammered into various shapes

Question 25

what is the use for high- carbon steel?

Answer 25

tools e.g. knives and screwdrivers

Question 26

what is the reason for high- carbon steel?

Answer 26

less malleable and stiffer than low- carbon steel

Question 27

what is the use for stainless steel?

Answer 27

cutlery, cooking utensils and kitchen sinks

Question 28

what is the reason for using stainless steel?

Answer 28

resists corrosion so stays shiny and clean

Question 29

what is the use of copper?

Answer 29

wires, cooking pans and water pipes

Question 30

what is the reason for using copper?

Answer 30

• good conductor of electricity
• good conductor of heat
• malleable and unreactive

Question 31

what is the use of aluminium?

Answer 31

• aircraft bodies
• power cables

Question 32

what is the reason for using aluminium?

Answer 32

• low- density and high strength
• low- density and conductor