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SAI INTERNATIONAL SCHOOL
CLASS-VIII
SUBJECT-CHEMISTRY
TOPIC-Materials: Metals and Non-metals
Sub-topic- Chemical property of metals and non–metals.

Reaction with Oxygen

LESSON NOTES

Chemical Property:-

A chemical property is a characteristic of a substance that may be observed when it
participates in a chemical reaction.

Let us study in detail about the chemical property of metals and non-metals.

1. Reaction of metals with oxygen. When metals react with oxygen, respective
metal oxides are formed. They are basic in nature.
E.g. When Magnesium ribbon is burnt in the presence of air, it burns with
dazzling white light to produce magnesium oxide.
2Mg + O 2 2MgO.
Magnesium + Oxygen Magnesium oxide.
MgO + H 2O Mg(OH) 2
Magnesium oxide + Water Magnesium hydroxide (basic)

When metal oxide (MgO) is dissolved in water and tested with litmus paper, it
turns red litmus blue showing that it is basic in nature.

In case of iron. Iron on exposure to moist air (oxygen and water vapour)
develops a brown colour coating of rust on its surface. This process is known
as rusting. It is an example of Corrosion.
Corrosion is the process of degradation of the metals due to long exposure to
the environment or chemicals.
The above chemical reaction can be written as
4Fe + 3O 2 + 2H 2O 2Fe 2O 3.H 2O
Iron + Moist air Iron Oxide (rust)
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