3.5.7 - Iron, Steel And Other Metals

Question 1

What is rusting !?

Answer 1

. Rusting is the 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

What two substances are required to form rust!?

Answer 3

. Oxygen

. Water

Question 4

How many stages are there to rusting!?

Answer 4

. It happens in two stages

Question 5

What is the FIRST stage of rusting ?!

Answer 5

Iron is oxidised by oxygen to form iron (III) oxide

Question 6

What is the SECOND stage of rusting!?

Answer 6

. Iron (III) oxide is hydrated by water.

Question 7

How do you prevent rusting !?

Answer 7

Either by :
. Using barriers
. Sacrificial protection
Or
. Galvanising

Question 8

What is the barrier method used to prevent rusting !?

Answer 8

. Coating the iron in paint, oil, grease or plastic, prevents the iron from coming in contact with oxygen or
water

Question 9

What is the disadvantage of the barrier method used to prevent rusting !?

Answer 9

. This only works as long as the coating is intact (As soon as it breaks rusting happens)

Question 10

What is the sacrificial protection method used to prevent rusting !?

Answer 10

. Attach a block of more reactive metal (E.g. magnesium) to the iron. This works by displacing the iron from the rust as soon as the rust forms.

Question 11

What is the disadvantage of the sacrificial protection method used to prevent rusting !?

Answer 11

. The block of magnesium has to be replaced often.

Question 12

What is the galvanising method used to prevent rusting !?

Answer 12

. This method specifically involves coating the iron in zinc

Question 13

What is the advantage of using the galvanising method used to prevent rusting !?

Answer 13

It works both ways:
. The coating prevents oxygen and water from coming in contact with the iron.
. (and even if a crack appears)
. Zinc is more reactive than iron, so acts as sacrificial protection as well.

Question 14

What is an alloy !?

Answer 14

. Alloys are mixtures of a metal with one or more of the elements usually other metals or carbon

Question 15

What are three common alloys !?

Answer 15

. Steel
. Brass
. Bronze

Question 16

What does the alloy steel consist of !?

Answer 16

. Iron + carbon

Question 17

What does the alloy brass consist of !?

Answer 17

. Copper + zinc

Question 18

What does the alloy bronze consist of !?

Answer 18

. Copper + tin

Question 19

What characteristics do alloys have that differ from pure metals !?

Answer 19

. Alloys are harder than pure metals because the different sized atoms or ions prevent the layers of metal ions sliding over each other. This means the alloy is less malleable.

Question 20

What is the use of iron !?

Answer 20

. Making steel

Question 21

Why do we use iron to create steel !?

Answer 21

. Steel is more useful than iron

Question 22

What is the use of low carbon steel !?

Answer 22

Ships, cars, bridges

Question 23

Why do we use low carbon steelto make ships etc!?

Answer 23

. As it is strong, but low carbon can be hammered into various shapes.

Question 24

What is the use of high carbon steel !?

Answer 24

. Tools, knives

Question 25

Why do we use high carbon steel to create tools!?

Answer 25

. High carbon steel is less malleable and stiffer than low carbon steel.

Question 26

What is the use of stainless steel!?

Answer 26

. Cutlery, cooking utensils

Question 27

Why do we use stainless steel to create cutlery !?

Answer 27

Cr forms an oxide layer that resists corrosion, so stays shiny and clean

Question 28

What is the use of copper !?

Answer 28

. Wires, cooking pans, water pipes

Question 29

Why do we use copper to create wires, pans and pipes!?

Answer 29

Excellent, conductor of electricity
Excellent, conductor of heat
Unreactive and malleable

Question 30

What is the use of aluminium!?

Answer 30

. Aircraft bodies
. Power cables

Question 31

Why do we use aluminium to make aircraft bodies!?

Answer 31

Low-density and high-strength