Mixtures

Question 1 What are mixtures. Give example?

Question 2 What are homogenous mixture. Give example?

Question 3 What are heterogenous mixture. Give example?

Question 4 Give few properties of homogenous mixture?

Question 5 Give few properties of heterogenous mixture?

Question 6 Differentiate between mixtures and compounds ?

Question 7 Why air is considered a mixture not a compound ?

MIXTURES
A mixture is a substance which consist of two or more elements or compounds not chemically combined together.

For Example Air is a mixture of gases like oxygen,nitrogen,argon,carbon dioxide etc.

Gun Powder is a mixture of potassium nitrate,sulphur,charcoal.

Brass is a mixture of copper and zinc.

The various substance present in a mixture are called as its constituents or components.

Types of mixtures:

1) Homogeneous Mixture

2) Heterogeneous Mixture

HOMOGENEOUS MIXTURE	HETEROGENEOUS MIXTURE
1) Those mixtures in which the substances are completely mixed together and are indistinguishable from one another.	Those mixtures in which the substances remain separate and one substance is spread throughout the other.
2) They have uniform composition throughout its mass.	They do not have uniform composition.
3) It has no visible boundaries of separation between various constituents.	It has visible boundaries.
4) For Example : Sugar solution,Salt solution,Alcohol and water,Soft drinks etc.	For Example: Sugar and sand, Salt and and,Milk,Soil,Blood,Starch,Muddy water etc.

Properties of Mixture

1) They can be separated into its constituents by physical processes (filtration,evaporation,sublimation,distillation)

2) A mixture shows the properties of all its constituents present in it.

3) Formation of mixture is a physical change ie energy (in the form of heat,light etc ) is usually neither given out nor absorbed in the preparation of a mixture.

4) The constituents are present in any proportion by mass.

5) They does not have definite melting and boiling point.

6) They can be homogeneous or heterogeneous.

DIFFERENCE BETWEEN COMPOUND AND MIXTURE

MIXTURES	COMPOUNDS
1)A mixture can be separated into its constituents by the physical processes.	A compound can not be separated into its constituents by the physical processes.
2)A mixture shows the properties of its constituents.	A compound does not shows the properties of its constituents.
3)Energy is usually neither given out nor absorbed in the preparation of a mixture.	Energy  is usually given out or absorbed during the preparation of a compound.
4)The composition of a mixture is variable,the constituents can be present in any proportion by mass.	The composition of a compound is fixed,the constituents are present in fixed   proportion by mass.
5) A mixture does not have a fixed melting and boiling point.	A compound has a fixed melting and boiling point.