Rusting, Steel, Aluminium And Iron (T2)

Question 0

What substances are BOTH needed for rusting to occur?

Answer 0

Water and oxygen

Question 1

What is rusting?

Answer 1

Rusting is a very slow chemical reaction that occurs when iron is exposed to air and water

It is the changing of iron to iron oxide (the state iron is found in)

Iron + air + water -> iron (III) oxide

The (III) means the oxide is made up of three atoms of oxygen

Question 2

As well as iron, what metal alloy rusts when it comes into contact with water and oxygen?

Answer 2

Steel

Question 3

Why does aluminium not corrode as easily as iron and steel?

Answer 3

Because it’s surface is protected with a layer of aluminium oxide

Question 4

What advantages does steel have over iron?

Answer 4

• harder and stronger

- less likely to corrode / rust

Question 5

What properties do iron and aluminium share?

Answer 5

• both are used to build cars
• both are malleable
• both are good electrical conductors

Question 6

List some advantages of using aluminium over steel or iron…

Answer 6

• lower density than iron or steel so it is lighter. In cars this results in improved economy
• does not corrode easily, so a car body made from aluminium may last longer

Question 7

What is a big disadvantage of using aluminium in manufacturing?

Answer 7

It is more expensive than steel.

Question 8

In the manufacture of cars, where is steel usually used, and why?

Answer 8

Steel is usually used for body panels and chassis, as it is strong and malleable

Question 9

In the manufacture of cars, where is copper usually used, and why?

Answer 9

Copper would be used for electrical wiring as it is a good conductor

Question 10

In the manufacture of cars, where is glass usually used, and why?

Answer 10

In the windows as it is transparent

Question 11

In the manufacture of cars, where is aluminium often used, and why?

Answer 11

For the body panels and interior fittings as it is light weight and rust proof

Question 12

In the manufacture of cars, where is plastic usually used, and why?

Answer 12

For the body panels, lights and dashboard as it is tough and easily moulded

Question 13

In the manufacture of cars, where are fibres usually used, and why?

Answer 13

For the seats and carpets as fibres are good heat insulators and can be woven

Question 14

According to European law, how much of a car’s materials must be recyclable?

Answer 14

85%, rising to 95% in 2015

Question 15

In industry, what steps are often taken to overcome the issue of rust?

Answer 15

Iron is often greased or covered in paint to prevent either air or water getting to the iron. This either slows or fully prevents the rusting process.

In some cases iron is replaced by steel as it is less likely to corrode and the process of corrosions takes longer.

Question 16

Describe “sacrificial protection” of iron in industry…

Answer 16

Rusting begins with the decay of iron atoms by the loss of an electron from the outer shell.

The loss occurs due to constant bombardment from oxygen atoms.

This loss of an electron begins the process of oxidation and destruction of the iron, or its conversion to iron oxide.

A ‘sacrificial node’ is a small block of a more reactive metal like Zinc or Magnesium. These decay more rapidly than the iron, so the iron takes the electrons from the other substance.

This accelerates the decay of the node but preserves the iron by feeding it electrons.

This “sacrificial protection” is being used more and more in high corrosion environments like ships, where sea salt accelerates corrosion.