Chapter:- 2

Is Matter around us Pure

Matter (Solid, Liquid or Gas)

  • Pure Substance,
  • Mixtures (No Fixed Composition)

Pure Substance

  • Elements (Cannot be broken down to simpler substances)

Examples:-

Copper, oxygen, iron, hydrogen, mercury etc.

  • Compounds (Have fixed composition can be broken down into elements by chemical or electrochemical reactions)

Examples:-

Water, methane, sugar, salt etc.

Mixtures (No Fixed Composition)

  • HomogeneousUniform composition
  • HeterogeneousNon-Uniform composition

Homogeneous (Uniform composition)

Examples:-

Sugar in water, salt in water, sulphur in carbon

disulphide, water in alcohol etc.

Heterogeneous Non-Uniform composition

Examples:-

Sand and salt, sugar, and salt water in oil etc.

Mixtures

When two or more substances (elements/ compounds) are mixed together in any ratio, but they do not combine chemically, a mixture is formed.

Types of Mixtures

Depending upon the nature of the components that form a mixture, we have two types of mixtures.

Mixtures (No Fixed Composition)

  • Homogeneous
  • Heterogeneous

Homogeneous Mixtures

Air, alloy, soda water etc.

Heterogeneous Mixtures

A mixture of oil and water suspensions colloids etc

Components of a Solution

  • Solvent
  • Solute

Solvent

The component of the solution that dissolves the other component in it (usually the component present in larger amount) is called the solvent.

Solute

The component of the solution that is dissolved in the solvent (usually present in lesser quantity) is called the solute.

Types of Solution

    Depending upon the amount of solute present in a given amount of solvent, the

    solution can be classified into following three classes

Types of Solution

  • Saturated Solution
  • Unsaturated Solution
  • Supersaturated solution

Saturated Solution

A solution in which no more amount of solute can be dissolved at a given temperature is known as saturated solution. The amount of solute present in the saturated solution at this temperature is called its solubility.

Unsaturated Solution

Some more amount of solute can be dissolved at a given temperature, is called unsaturated solution.

Supersaturated Solution If solution contains more amount of solute than the saturation concentration, it is called supersaturated solution.

Properties of a Solution

  • A solution is a homogeneous mixture.
  • The particles of a solution are smaller than 1 nm (10-9m) in diameter. therefore, they cannot be seen by naked eyes.
  • Due to very small particles size, they do not scatter a beam of light passing through the solution. So, the path of light is not visible in a solution.
  • A solution is stable. The solute particles cannot be separated by the process of filtration, also they do not settle down when left undisturbed.

 Concentration of a Solution

The amount of solute present in a given amount of solution.