States Of Matter

Liquids contain particles which are free to move within the substance. Therefore liquids are able to flow or one can say that liquids do not have a definite shape. The movement of liquid particles helps to acquire the shape of the container in which it is kept in. They have definite volume due to the intermolecular forces of attraction, and are slightly compressible than solids.

Common salt, sugar belongs to the category of compounds which are pure substances. Iron is an element which is a pure substance. Rain water is a mixture of water and certain minerals, and mixtures are classified under impure substances.

Air is a homogenous mixture which contains approximately 78% nitrogen, 21% oxygen and about 0.04% carbon dioxide. Hence the component which is absent in air is chlorine.

Butter is colloidal in nature belonging to the category of gels. This means that the dispersed phase is liquid and the dispersing medium is solid. In short, butter is an example for liquid in solid.

Homogenous solutions are mixtures in which the composition of the constituents is uniform throughout. The constituent particles cannot be distinguished using naked eye or microscope.

Example: Brine solution

Heterogeneous solutions are mixtures in which the constituent particles do not mix uniformly. The constituent particles are visible to naked eye and can be separated easily.

Example: Mixture of water and oil

The diagram is shown below:

(a) The suspension is a type of heterogeneous mixtures in which the solute particles do not dissolve but remain suspended throughout the bulk of the medium.

Example: Mixture of water and chalk dust

(b) The colloidal solution is a type of heterogeneous mixtures in which a material is evenly suspended in a liquid. The particle size of colloids is greater than that of true solutions but less than that of suspensions.

Example: Milk

a. The phenomenon of scattering of a beam of light by the colloids is called Tyndall effect. Tyndall effect is observed when sunlight passes through the canopy of a dense forest.

b. The random zig-zag motion of colloidal particles suspended in a liquid or gas medium is called Brownian movement or Brownian motion. This random motion is caused due to the collision of the colloidal particles with the particles of the medium.

The diagram is shown below:

Solvents are substances which dissolve the solute particles in it. The solvent is present in large quantities when compared to the solute.

Water is a good solvent. Petrol, alcohol are examples of other solvents.

The particles in gases are bound by weak intermolecular forces of attraction. Therefore the particles have high kinetic energy and can move freely in the space available to them. Thus gases do not have a definite shape and volume.

Ornamental gold (the most popular one is 22-carat gold) consists of both gold and copper. The composition of gold and copper is uniform throughout in ornamental gold and cannot be distinguished using naked eyes or microscope. So, ornamental gold is said to be a homogeneous mixture.

The composition of a mixture containing sand and iron fillings is not uniform. Also, the sand and iron fillings can be easily distinguished using naked eyes and can be separated easily. Such mixtures are called heterogeneous mixtures.

Water can dissolve a large number of substances in it. Also, it is the only liquid that can dissolve a most number of substances than any other solvent.

This is the reason why water is called the universal solvent.

The size of particles of a suspension is large. So, when a beam of light is passed through a suspension, these particles scatter the light beam making its path visible (as shown in the diagram below)

1-(c), 2-(a), 3-(d)

Explanation:

Sodium chloride is a compound formed by the elements sodium and chlorine.

Compounds belonging to the class of pure substances.

Milk is a colloid and colloids are heterogeneous mixtures which fall under the category of impure substances.

Air is a homogenous mixture consisting of various gases mixed uniformly such that one cannot distinguish the components of the mixture with naked eye or microscope.