Study Guide for Matter Test
ATOM
Molecules are made of
2 or more atoms put together
MOLECULE
(So molecules are much bigger
Than atoms!!)
ATOM
Atoms combine into molecules.
O is an atom; O2 is a molecule: both are
oxygen.
An Atom looks like this
Atomic Number
tells how many
particles are in the
atom. This number
tells you what
Element it is.
Atoms are made of 3 particles:
Protons
Positively charged
particles; in the nucleus
Ex: Atomic Number
of 2 means there
are 2 of each
particle. This would
be an atom of
Helium (He).
Neutrons
Neutral particles in the
nucleus; NO CHARGE
Electrons
Nucleus
Negatively charged
particles; OUTSIDE the
nucleus
Center of the Atom; contains
Protons and Neutrons
States of Matter
Certain shape and volume
Cold;
Less
energy
Volume and shape
depends on
container
Certain volume –
shape of container
Solid
Liquid
Ice
Water
H2O
Gas
Steam
H2O
Melts to form
H2O
Evaporates to form
When a substance changes temperature it can change its state of matter, but it will
,m
not change chemically. (Doesn’t form a new substance).
Molecules in a solid are
very close together – don’t
move very much
Molecules in a liquid are a
little farther apart – they
can move and slide around
To change from one state of matter
to another requires the addition or
subtraction of HEAT (energy)
Heat
Heat
Solid
Liquid
Molecules in a gas spread
out as far as they can– they
move very fast
Gas
Hot;
More
energy
Physical vs. Chemical Changes
Chemical change – a substance
actually changes to something else.
Physical change – a substance
changes appearance, but it is still
that substance.
When paper burns
part of it turn to
smoke and part of it
turn to ash.
When ice melts it
changes appearance
but it is still water.
Examples – melting, boiling, breaking,
cutting, ripping, dissolving, change
in state of matter.
Yes – Physical
Change
Question: afterward is it still
the same substance?
No – Chemical
Change
Evidence a Chemical change took place
Bubbles – evidence that a new gas is formed (but soda pop fizzling is a physical
change, though. Why?).
Turns cloudy – evidence that a new solid is forming.
Heat (Temperature changes) – evidence that chemical bonds are breaking or
forming.
Color changes – evidence that a new substance is forming.
Change in smell or taste– evidence a new substance formed.
Light – evidence a new substance is formed.
New substance with
new properties
Chemical and Physical Properties
Physical Properties – you use your
senses to observe. “things it can do
alone”
Chemical Properties – You have to
test to find. How a substance reacts
to other substances
States of Matter – solid, liquid, gas.
Is it flammable?
Color, texture, shape, smell, density,
freezing point, melting point…
Does it react with water?
Is it magnetic?
Does it rust?
A chemical change creates a change in physical and chemical
properties!!