Page 40 - ICSE Chemistry 6

Heterogeneous Mixture

A mixture in which the components can be easily seen and are not uniformly distributed is called a
heterogeneous mixture. Mixtures of sand and gravel, oil and water are examples of heterogeneous mixtures.

Activity 2.4

Aim: To show that proper es of a mixture depend on the quan ty of the cons tuents present
Materials required: Some drinking water, 3 glass tumblers, one spoon, 9 spoonful of lemon juice

Procedure
• Take three glass tumblers. Fill half of each tumbler with drinking water.
• Add a spoonful of lemon juice in the fi rst tumbler and s r to mix.
• Add three spoonfuls of lemon juice in the second tumbler and s r to mix.
• Add fi ve spoonfuls of lemon juice in
the third tumbler and s r to mix.

• Taste the three solu ons one by one.
Observa on: All the samples are sour.
However, the degree of sourness varies.

Conclusion: In all the three cases, although
a homogeneous solu on is obtained,
1 2 3
the property diff ers depending upon the
a spoonful of lemon three spoonfuls of fi ve spoonfuls of
concentra on of the cons tuents present. juice added lemon juice added lemon juice added

Differences between Compounds and Mixtures

Let’s understand the diff erences between compound and mixtures with the help of iron powder and
sulphur powder. Firstly, when iron powder and sulphur powder are mixed and then heated, a material
iron sulphide (FeS) is formed. It is an en rely diff erent product having diff erent proper es from iron and
sulphur. Iron and sulphur combine chemically on hea ng in the ra o of 7:4 by mass to form iron suphide.
Thus, iron sulphide (FeS) is a pure substance and is called a compound.

Iron + Sulphur heat Iron sulphide
Again, when iron powder and sulphur powder are mixed and no heat is given, they do not react to form
any other substance. Thus, they form a mixture of two substances that can be separated easily. Iron
powder is separated by using a bar magnet because iron gets a racted by a magnet and the powder
le behind is sulphur which does not get a racted by a magnet. Sulphur is soluble in carbon disulphide
whereas iron sulphide is neither a racted by a magnet nor soluble in carbon disulphide.
Diff erences between compounds and mixtures are given in Table 2.8.

Table 2.8: Diff erences between Compounds and Mixtures
Compounds Mixtures
• A compound is a pure substance. • A mixture is an impure substance.
• In case of compounds, the constituents are present in • In case of mixtures, the constituents can be present in
a ϐixed ratio. any ratio.

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