2.36 understand the sacrificial protection of iron in terms of the reactivity series.

Sacrificial is covering a metal with a more reactive metal. What this means is water and/or air will react with the more reactive metal instead of the one underneath.

2.35 describe how the rusting of iron may be prevented by grease, oil, paint, plastic and galvanising

Grease, oil, paint and plastic prevent air and/or water from coming into contact with iron. This means the reaction that rusts iron can't occur.

Galvanising is coating in zinc. This Zinc react in the air to form ZnCO3 which prevents air and/or water from coming into contact with the iron.

2.34 describe the conditions under which iron rusts

Water and oxygen are needed to rust iron: iron that reacts with these becomes hydrated iron(iii) oxide.

2.33 understand the terms redox, oxidising agent, reducing agent

In a redox reaction, a more reactive metal gains an oxygen from a less reactive metal which looses it.
i.e. a more reactive metal is oxidised and a less reactive metal is reduced.

The reducing agent is the more reactive metal which reduces the other metal.
The oxidising agent is the less reactive metal which allows the other metal to be oxidised.

2.32 understand oxidation and reduction as the addition and removal of oxygen respectively

oxidation is the gain of oxygen,
reduction is the loss of oxygen.

2.31 deduce the position of a metal within the reactivity series using displacement reactions between metals and their oxides, and between metals and their salts in aqueous solutions

A metal oxide or a metal salt dissolved in water:

• introduce a more reactive metal and it will displace the current one
• introduce a less reactive metal and no displacement will take place

From this you can deduce which metals are more and less reactive.

2.30 describe how reactions with water and dilute acids can be used to deduce the following order of reactivity: potassium, sodium, lithium, calcium, magnesium, zinc, iron and copper

potassium, sodium, lithium and calcium all react with water and acids
magnesium, zinc and iron all react with acids (and very slowly with water.)
copper doesn't react with either.

The more vigorous the reaction the more reactive the metal. The more things a metal will react with, the more reactive the metal.

2.29 understand that metals can be arranged in a reactivity series based on the reactions of the metals and their compounds

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