Download Matter

Matter
Chemistry is
…the study of the composition,
structure and properties of
MATTER, the changes which
matter undergoes and the energy
that accompanies these changes.
What is matter?
•EVERYTHING!
– Except energy: heat, light, sound. . .
2 Categories of Matter
Substance
Mixture
• Element
• Physical
– Collection of the
combination
same type of atom
elements and/or
– Cannot be
compounds or
decomposed
both.
• Compound
• USUALLY
– 2 or more different
heterogeneous
atoms chemically
bonded together.
Atom
• Neutral particle
• Consists of subatomic particles
–Protons, neutrons & electrons
Element?
Compound?
Mixture?
Substance?
Element?
Compound?
Mixture?
Substance?
?
???????
• Elements are represented
with symbols
• DIATOMIC Elements
–The simplest form of these
elements is a pair of atoms
Go to 7 and
make a 7. Don’t
forget Hydrogen!
Characteristics of a
Compound
• Individual atoms lose their
original properties after bonding
• Composition is fixed
• can be decomposed / broken
down
Compound vs. Molecule
• Molecule: applies only to
bonded non-metal atoms
H2O
O2
CO2
C6H12O6
NaCl
Which are molecules?
Which are compounds?
SOLUTION
Only mixture that is homogeneous
NaCl(s) + H2O(l)  NaCl(aq)
solute
solvent
aqueous solution
Other solutions include Air (mixture of gases)
&
Alloys (mixture of metals)
Physical vs.
Chemical
Physical Properties & Changes
• determined without changing the
chemical composition of the substance
Examples….
Color, shape, odor, malleability, brittleness,
does it conduct electricity, does it conduct heat?
state of matter (s), (l), (g)
Melting point, boiling point…
mass
volume
density D = m/v
…and
absorption
angular momentum
area
capacitance
concentration
dielectric
ductility
distribution
efficacy
elasticity
electric charge
electrical impedance
fluidity
frequency
inductance
Intrinsic
impedance
Intensity
irradiance
length
location
luminance
luminescence
luster
magnetic field
magnetic flux
momentum
opacity
permeability
permittivity
plasticity
radiance
resistivity
reflectivity
refractive index
spin
solubility
specific heat
strength
temperature
tension
viscosity
Can be
intensive or extensive
• DON’T depend
on sample size
• useful in
identifying
substances
• Ex. density
• DO depend on
sample size
– volume
– weight
– mass
Chemical Properties
• determined during a chemical
reaction with another
substance
–Ex. Is it toxic, is it flammable,
does it rust, does it tarnish,
does it corrode…?
Chemical Change/
Chemical Reaction
• Results in the rearrangement
of atoms
to form a new substance
BUT!!! We can’t see atoms so
how do we know a chemical
reaction has taken place?
The End