Rusting ©cgrahamphysics.com 2016

What do they all have in common?

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Can you match the word with the picture?

• rusting

• corrosion

• unreactive

• metal oxide

• tarnishing

• patina

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9F Keywords

metal oxide

tarnishing

unreactive

patina

rusting

corrosion

a compound containing only a metal and oxygen

a metal breaking down by reacting with oxygen (and sometimes moisture)

to gather a thin layer of discoloration by reacting with the air

describes a material that does not react

a thin layer of green on the surface of copper

the corrosion of iron, which reacts with oxygen and water to form flaky iron oxide

rusting corrosion

unreactive metal oxide

tarnishing patina

Starter: match the word to its meaning

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Aim • Explain what rusting is • Describe the conditions under which iron rusts Keywords • rusting • corrosion • unreactive • metal oxide • tarnishing • patina

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Have you ever wondered

The bigger picture

Can only iron rust?

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Only iron can rust

• Only iron and iron alloyes can rust

• Since steel is made of iron it can also rust

• The chemical name for rust is iron oxide

• Although other metals react with oxygen, their oxides are not called rust

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What affects the speed of rusting?

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Set up an experiment with 4 iron nails

CONTROL Tube 1

Calcium chloride powder and bung

Tube 2

Boiled water with oil film and bung

Tube 3

Salty water

Look at the pictures carefully – your experiment should be set up just like this:

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iron oxide

oxygen + iron

Rusting Rusting is an ‘unhelpful’ chemical reaction but it is unfortunately very common. Rusting only occurs with the metal iron. It is the reaction of iron with oxygen in the presence of water to form iron oxide (rust).

2Fe2O3

3O2 + 4Fe

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Calcium chloride

powder and bung

Water and air Boiled water with oil film

and bung

Salty water

Use the internet to fill out these boxes

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Calcium chloride

powder and bung

Water and air

Boiled water with oil film

and bung

Salty water

Plenary: make your predictions

It will go slightly

rusty ©cgrahamphysics.com 2016

Key words • Rusting - the corrosion of iron, which reacts with

oxygen and water to form flaky iron oxide

• Corrosion -a metal breaking down by reacting with oxygen (and sometimes moisture)

• Unreactive - describes a material that does not react

• metal oxide - a compound containing only a metal and oxygen

• Tarnishing - to gather a thin layer of discoloration by reacting with the air

• Patina - a thin layer of green on the surface of copper

©cgrahamphysics.com 2016