2. Democritus
“matter was
empty space
filled with
tremendous
numbers of
tiny particles
called ATOMS”
5th century BC
Aristotle
did not
support
Democritus’
theory on
molecules.
1600’S
Some scientist
support the
theory and
some
evidences on
small particles
and the space
around them
sprouted.
1700’s
3. ATOMS
One of the smallest parts that any substance can be
divided into,that combines with other atoms that make
a MOLECULE.
4. Pure substances
Elements
A simple chemical
substance compose of
single atom
E.g. hydrogen(H)
oxygen (O)
carbon (C)
Compound
Something that consist
of a combination of
two or more atoms
E.g. Water (H₂O) a
combination of
hydrogen and oxygen
5. molecules
The smallest unit into which any substance
can be divided without losing its own
chemical nature.
E.g. Gold*
*even if a gold is broken into two, they are still golds.
6. Molecules Interact
Cohesion
Attractive force between
same kind of molecules.
Adhesion
The ability where one
kind of molecule attracts
and clings to a different
kind of molecule.
13. Plasma*-
Occur at extremely high
temperature and are made up of
charged part of atoms.
*rare phase of matter
14. At higher temperature, the molecules of a
substance move faster with increased agitation
and then they move a little faster apart thus
expanding the substance. As the substance cools
down, the motion slows and the molecular forces
are able to pull the molecules closer together.
15. Temperature of a gas is proportional to the
average kinetic energy of the gas molecule.(e.g.
ammonia molecules have greater average velocity
at a higher temperature and a slower average
velocity at lower temperature)
Kinetic energy involves the mass of the molecules
as their velocity:
( KE = ½ mv² )- ( d= gt²/2 )
