Important Definition:
- Matter: Any substance which have mass and occupy space is called matter. There are 5 states of matter in which 3 are most popular. That are solid, liquid, gas , B.E.C (Boss Einstein condensate) , and plasma.
- Compare solids, liquids and gases:
| Solid | Liquid | Gas | |
| Volume | fixed | fixed | not fixed |
| Shape | fixed | take the shape of container | take the shape of container |
| Intermolecular Spaces | Least | more than solid | Most |
| Rigidity | solids are rigid | not rigid | not rigid |
| Intermolecular force of attraction | highest | less than solid | least intermolecular force of attraction |
- Define the following terms:
- Evaporation: The process of conversion of liquid into solid below it’s boiling point. It is a surface phenomenon. It depends on factors. It causes cooling.(i) Surface Area: Evaporation increases with increase in surface area as per molecules get more energy. (ii) Humidity: Evaporation decreases with increase in humidity as more water vapours present in air do not allow further evaporation(iii) Temperature: Evaporation increases with increase in temperature as it increase kinetic energy of particles. (iv)Wind speed: As wind speed increases rate of evaporation increases as water vapours in the air blown away.
- Boiling: The process of conversion of liquid to vapour at its boiling point. It is bulk phenomenon. It causes heating.
- Condensation: The process of conversion of vapour (gas) into liquid.
- Solidification: The process of conversion of liquid into solid.
- vaporization: The process of conversion of liquid into gas
- Sublimation: The process of conversion of solid directly into gas without passing liquid state. The substance which show the property are called sublime. Examples dry ice (solid carbon dioxide), Naphthalene, camphor, ammonium chloride.
- Deposition: The process of conversion of gas directly into solid without passing liquid state.
- Diffusion: Intermixing of particles on their own is known as diffusion. Diffusion takes place from higher concentration to lower concentration. Rate of diffusion is as Gas>liquid >solid. On increasing temperature, rate of evaporation increases as kinetic energy of particles will increase.
- Melting: The process of conversion of solid into liquid.