Question

Write down the differences between
a) Elements and compounds
b) Compounds and mixtures
c) Physical and chemical change.

Answer 1

A. Element

1.Element are pure substances which consist of only one type of atom.e.g carbon (C) ,oxygen (O) .

2.Element cannot be broken down into simpler substance even by chemical means.

Compound

1.Compound are made up of two or more elements combined in a fixed proportion by weight.e.g water (H2O),ammonia (NH3).

B.Compound

1.Compound are the substance made up of atoms of two or more elements combined together in a fixed proportion.

2. Compound have definite formula.

3.Compound are always homogeneous.

Mixtures

1.Mixtures are made up of two or more pure substances mixed in any proportion.

2.Mixtures do not have any formula.

3. Mixtures may be homogeneous or heterogeneous.

C.physical change

1.no new substance is formed

2.temporary change.

3.reversible change.

Chemical change

1. new substance is formed.

2.permanent change.

3.irreversible change.