20-11-2012, 04:26 PM
Classification of Matter
[attachment=40401]
Physical and Chemical Changes
All reaction in Chemistry can be divided into two types of changes: Physical or Chemical.
Physical Change:
NO new substance is formed.
These changes are easily reversible or temporary.
An example is dissolving salt in water.
Other examples of physical change include: melting, boiling, mixing 2 solids or liquids.
Chemical Change:
A NEW substance is formed.
These changes are irreversible or permanent.
The new substance formed will have different properties compared to its original elements. (E.g. different melting and different chemical reactions from the original substance.)
Conclusion
An element is a pure substance which cannot be split up into two or more simpler substances by chemical means.
A compound consist of a fixed number of different kinds of atoms chemically combined together.
A mixture is not a pure substance as it contains a mixture of atoms of molecules which are not chemically combined together.
[attachment=40401]
Physical and Chemical Changes
All reaction in Chemistry can be divided into two types of changes: Physical or Chemical.
Physical Change:
NO new substance is formed.
These changes are easily reversible or temporary.
An example is dissolving salt in water.
Other examples of physical change include: melting, boiling, mixing 2 solids or liquids.
Chemical Change:
A NEW substance is formed.
These changes are irreversible or permanent.
The new substance formed will have different properties compared to its original elements. (E.g. different melting and different chemical reactions from the original substance.)
Conclusion
An element is a pure substance which cannot be split up into two or more simpler substances by chemical means.
A compound consist of a fixed number of different kinds of atoms chemically combined together.
A mixture is not a pure substance as it contains a mixture of atoms of molecules which are not chemically combined together.