Chemistry ; what i have learnt

1) kinetic particle theory

Solid - particles of solid are held together by very strong forces of attraction and do not move freely, and they only have enought kinetic energy to vibrate and rotate abour their fixed positions. therfore their fixed shape, the particles of solid are very close together so solid is unable to be compressed

Liquid - particles of liquid are helf together by a weaker forces compared to solid, they move freely and slide over one another thus they don't have a fixed shape, the particles are also quite closely packed together so they cannot be compressed

Gas - particles of liquid are held together by a very weak force and gas has a lot of kinetic energy held in fixed position therefore their fixed shape. The large space in between gases are also the result gas can be compressed easily so it does no has a fixed volume

Changes of state

-Melting
as heat energy is being supplies the particles vibrate faster until the vibrations overcome the attractive forces between particles and it starts to break away from it's fixed position, it slide over one another and become a liquid

-Freezing
particles lose kinetci energy and begin to move more sloqly, when the temperature is low enough the particle start to settle into fixed positions, after it is settled in their respective fixed postition, it is now a solid.

-Boiling
as the particle gain kinetic energy it move faster and eventually having enought energy to overcome the forces holdining them together, they spread far apart and move rapidly in random directions, now it is a gas.



Heating curve of a solid ; melting process (not so curvy though)

Cooling curve of liquid (Freezing process)

Heating curve of liquid (boiling process)