Brass is not a pure substance. It is a mixture.

Air is a mixture, because samples from different places give different percentage of its components.

In a solution, the component present in lesser amount by weight is called solute and the component present in larger amount by weight is called solvent.

Gaseous state of matter has the highest kinetic energy

 Water can be compressed, has less density, high kinetic energy, attractive forces are not so strong, can flow easily so it is possible to row a boat in water but not pass through a wooden fence.

Boiling refers to the process by which a substance changes from the liquid state to the gaseous state at its boiling point.

A substance absorbs heat energy and it melts. The temperature at which a substance melts is called as melting point.

As solid particles are tightly packed, held together by strong force, particles cannot move.

After the filteration of a solution the liquid that collected is called filtrate.
In the process of fractional distillation the clear liquid collected is called distillate.

Charcoal adsorbs gases on its surface. Charcoal is called the adsorbent and the gas is called the adsorbate.

Centrifugation: This is used to separate very fine and tiny particles of solid which do not settle down easily in a liquid. The mixture taken in a centrifuge tube is centrifuged (by rotation) in a centrifuging machine, so that the solid gets deposited at the bottom of the tube and the clear liquid (supernatant) is decanted.
Applications of centrifugation:
(1) Centrifugation technique is used in cream separator in diaries
(2) In removing fat from milk to produce skimmed milk
(3) In separation of blood components & urine components in forensic science.
(4) Medium sized centrifuges are used in washing machine to wring water out of fabrics