Matter in Our Surrounding Notes

Solid state:

Solid

Fixed shape

Fixed volume

Solids are rigid, and have negligible compressibility:

Reason:

• Molecules are closely spaced and the intermolecular separation is very small which cannot be reduced further.

Matter can be change from one state to another by:

• Changing the temperature
• Changing the pressure

Effect of Change of Temperature:

• On increasing the temperature, a solid can be converted into liquid state; and a liquid can be converted into gaseous state.
• On decreasing the temperature, a gas can be converted into liquid state. And a liquid can be converted into solid state.

• When a substance changes phase, that is it goes from either a solid to a liquid or liquid to gas, it requires energy to do so. The potential energy stored in the in the substance needs to be overcome by the kinetic energy of the particles which is due to the motion of the particles before the substance can change phase.
• The energy required to change the phase of a substance is known as a latent heat. The word latent means hidden.

Phase changes are indicated by flat regions where heat energy used to overcome attractive forces between molecules