1. Pure: The matter which has only single category of particles which has similar chemical properties is called pure substance
2. Mixture:The physical or chemical combination of more than one type of element is known as a mixture.

1. Homogeneous: In a mixture where all the particles are uniformly combined then it is said to be a homogeneous mixture. Its particles can’t be separated easily. Ex: Sugar and water.
2. Heterogeneous: In a mixture where the particles are not uniformly combined, that is a heterogeneous mixture. Its particles could be separated easily. Ex: Sand and water.

• Solvent: The component of solution that dissolves other component into it. It is usually present in a large amount in solution.
• Solute:The component of solution that is dissolved in the solvent. It is usually present in a small amount in solution.

• Solution is a homogeneous mixture.
• Its particles are smaller than 1nm (10-9 meter) in diameter.
• Cannot be seen by naked eyes.
• They do not scatter a beam of light passing through the solution.
• The solute particles cannot be separated from the mixture by the process of filtration.

• Saturated Solution: When no more amount of solute can be dissolved in a solution, at a given temperature.
• Unsaturated Solution: When more amount of solute can be dissolved in a solution, at a given temperature.
• Solubility: The amount of solute present in a saturated solution, at a given temperature.

Concentration of solution = Amount of solute / Amount of solution
Or
Amount of solute/Amount of solvent

1. Mass by mass percentage of a solution:

   Mass of Solute × 100
   Mass of Solution

2. Mass by volume percentage of a solution:

   Mass of Solute × 100
   Volume of Solution

1. It is a heterogeneous mixture.
2. Particles can be seen by the naked eyes.
3. It scatters a beam of light passing through it and makes its path visible.
4. The solute particles settle down when a suspension is left undisturbed.
5. A suspension is unstable.
6. They can be separated from the mixture by the process of filtration.

1. A colloid is a heterogeneous mixture.
2. The size of particles of a colloid is too small to be individually seen by naked eyes.
3. Colloids are big enough to scatter a beam of light passing through it and make its path visible.
4. They do not settle down when left undisturbed, that is, a colloid is quite stable.
5. They cannot be separated from the mixture by the process of filtration.
6. A special technique of separation known as centrifugation can be used to separate the colloidal particles.
7. This scattering of a beam of light is called the Tyndall effect after the name of the scientist who discovered this effect.

Tyndall effect can also be observed when a fine beam of light enters a room through a small hole. This happens due to the scattering of light by the particles of dust and smoke in the air.

• Heterogeneous mixtures can be separated into their respective constituents by simple physical methods like handpicking, sieving, filtration, etc.
• Sometimes special techniques have to be used for the separation of the components of a mixture.

1. Evaporation: The process of separating the volatile (easily evaporated at normal temperatures.) components from its non- volatile solute is called evaporation. Example: ink the mixture of dye in water.
2. Centrifugation: The process in which denser particles are forced to the bottom whereas the lighter particles stay on the top when spun rapidly. Example: milk and cream.
3. Sublimation: The process of separating the sublime (change directly into vapor when heated,) volatile components from the non-sublime impurity in a mixture. Example: camphor and salt.
4. Chromatography: Kroma in Greek means color. This process is used for separation of the solute that dissolves in the same solvent. Example: black ink in a single color.
5. Distillation: The process of separating two miscible (forming a homogeneous mixture when added together.) liquids that boil without decomposition and have sufficient difference in their boiling points. Example: mixture of acetone and water.
6. Fractional Distillation: The process separating more than 1 miscible liquid by heating up them at their boiling points. There are certain fractional columns in the apparatus to do so. Example: different gases from the air.
7. Crystallization: This method is used to purify solids. It separates a pure solid in the form of its crystals from a solution. Example: Copper Sulphate from an impure sample.

• Elements: Robert Boyle defined an element as a basic form of matter that cannot be broken down into simpler substances by chemical reactions.
• Compunds: The substance composed of two or more elements, chemically combined with one another in a fixed proportion.
• Mixture: Elements or compounds just mix together to form a mixture and no new compound is formed.