CHANGE OF STATES
Book:Cambridge IGCSE
Page 3
HOMEWORK
BOOK- IGCSE CHEMISTRY WORKBOOK
PAGE- 2,3
Ex- 1,2,3
WE NEED TO REMEMBER
***All matter is made up of particles. Different type of
matter contain different type of particles(atoms and
molecules).
***Particle vibrating(moving) on a spot ALL the TIME.
*** The PRESSURE of a gas produces by the
particles(atoms or molecules) hitting the container. The
more heating the more PRESSURE is occurs.
KINETIC PARTICLE THERY in
EXPLAINING CHANGING
PROCESSES OF STATES.
Changing From SOLID to LIQUID
***MELTING- is happens with ABSORPTION of thermal
energy(HEAT) by particles.
*** Every substance start to melt at its own MELTING POINT (M.p).
WHY?
???Why some substances melt at higher
temperature. (has high melting point) ?
ANSWER: Particle hold together strongly
MELTING Process by Kinetic Particle Theory
1)Temperature raised and particles gain energy
2)With gained energy particles start to vibrate more
faster
3)Particles occupy more space which cause the
solid to expand
4) Particles have enough energy to break the forces
holding the lattice together
5) Particles can move around but still hold together-
Solid MELTS.
***EVAPORATING can occur at any
temperature
*** BOILING can occur only at Boiling Point
of substance
EVAPORATING AND BOILING
1)By Heating particles get more and more energy
2)Particles move more faster and the liquid expands
3)Some particles now have enough energy to escape
from the surface EVAPORATING takes place.
4)The higher temperature, the more particles have
enough energy to escape the surface Evaporation is
faster
5) At the Boiling Point, the particles have enough
energy to break the forces attracting them each other
6) Particles move very fast and separate from each
other The liquid Boils
7)Particles spread far apart and move randomly
BOOK- IGCSE WORKBOOK
EX-