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MATTER
Chapter 2
Physical Science
Matter Vocabulary
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Chemistry
Matter
Element
Atom
Compound
Molecule
Chemical Formula
Pure Substance
Mixture
Miscible
Immiscible
Pressure
Viscosity
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Energy
Evaporation
Condensation
Sublimation
Chemical property
Reactivity
Physical property
Melting point
Boiling point
Density
Buoyancy
Chemical change
Physical change
A. What is Matter?
I. Chemistry: the study of matter and how it
changes
II. Matter
1. Matter: anything that has mass and
occupies space
2. Element: a substance that cannot be broken
down into simpler substances
3. Atom: the smallest particle that has the
properties of an element
4.
Each element has a
one or two letter
symbol (atomic
symbol) used world
wide to designate itthere are more than
110
a. Example:
C=carbon,
Cu=copper
5. Compound: a substance made of atoms of more
than one element bound together
a.
b.
Each compound is
unique and different
than the elements
bound that comprise it
Iron (III) oxide= rust,
comprised of 2 atoms
of iron and 3 of
oxygen
6. Molecules: the smallest unit of a substance that
exhibits all the properties characteristic of that
substance
a. May be made of the
same atom or
different ones
b. Example: water
(H2O), oxygen (O2),
hydrogen (H2)
7. Chemical formula: the chemical symbols and
numbers indicating the atoms contained in the basic
unit of a substance
a.
b.
Example: CO2- carbon dioxide, 1 carbon and
2 oxygen
The number after and below the atomic symbol
indicates the number of that element
1. Example: C16H10N2O2 = 16 carbon, 10
hydrogen, 2 nitrogen, and 2 oxygen
c. The number place in front of a chemical
formula indicates the number of that molecule
Example: 3H20 = 3 water molecules
Pure substance: any matter that has a fixed
composition and definite properties
a. Cannot be broken down by physical means
such as boiling, melting, and grinding
Mixture: a combination of two or more pure
substances
a. Can be separated into different parts
i.
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b. A compound is different from the elements that
comprise it, while a mixture may have some of the
properties similar to the pure substances that make it
c. Heterogeneous mixture: a mixture that
substances aren’t uniformly mixed
1. Example: flour and water
d. Homogeneous mixture: a mixture that
substances are uniformly mixed and will not
settle out over time
1. Example: salt and water
e. Miscible: describes two or more liquids that are
able to dissolve into each other in various
proportions
1. Example: gasoline
Immiscible: describes
two or more liquids that
do not mix into each
other
1. Example: water and
oil
g. Gases can mix with
liquids such as
carbonated drinks and
oxygen into water
f.
B. Matter and Energy
a. Kinetic theory
1. Main points:
a. All matter is made of atoms and
molecules that act like tiny particles
b. These tiny particles are always in
motion- the higher the temperature, the
faster the particles
c. At the same temperature, more
massive (heavier) particles move slower
than less massive (lighter) particles
2. This is the cause for the differences in a solid,
liquid, and gas
a. Gases: particles are in constant state of motion
and rarely stick together
b. Liquids: particles are closely packed, but they
can still slide past each other
c. Solids: particles are in a fixed position
3. Gases are free to spread in all directions
a. Pressure: the force exerted per unit area of a
surface
b. All the atoms of a gas hitting the wall of a
balloon can cause this pressure
c. If the pressure is too great, the item will burst
4. Unlike a gas, a solid doesn’t need a container to
have shape- solids have volume and shape
5.
Liquids, also, take the shape of the container
a. Since a liquid and gas can spread, they are
said to be fluid
b. Viscosity: the resistance of a fluid to flow
1. The stronger the attraction between
particles, the slower the fluid will flow
2. Example: the viscosity of honey and
water
ii. Energy’s Role
1. Energy: the ability to change or move matter
2. Energy must be added to cause melting or
evaporation
a. As atoms gain energy, they vibrate faster,
and eventually break away from their fixed
position
b. Evaporate: the change of a substance from
liquid to a gas
3. Condensation: the change of a substance from a
gas to a liquid
a. Energy is
transferred from the
substance to the
surroundings
4. Some substances
don’t have a liquid
form at normal
temperature and
pressure
a. Example: carbon dioxide and sometimes water
b. Sublimation: the
change of a substance
from a solid to a gas
5. Changing state does not change the composition
or mass of the matter
6. The law of conservation of mass: mass cannot be
created or destroyed
7. The law of conservation of energy: energy cannot
be created or destroyed
C. Properties of Matter
*Chemical and physical properties
1. Chemical property: the way a substance reacts
with others to form new substances with different
properties
a. chemical properties describe how a
substance combines
b. Reactivity: the ability of a substance to combine
chemically with another substance
c. Flammable: a
chemical property that
describes whether
substances will react in
the presence of oxygen
and burn when
exposed to a flame
2. Physical property: a characteristic of a substance
that can be observed or measured without changing
the composition of the substance
a. Examples: shape, color, odor, texture, strength
b. Melting point: the temperature at which a solid
becomes a liquid
c. Boiling point: the temperature at which a liquid
becomes a gas below the surface
3. Density: the mass per unit volume of a substance
a.
b.
Density is a physical
property
Formula: D=m/V or
density =
mass/volume
c. Normally measured in g/cm3
Buoyancy: the force
with which a more
dense fluid pushes a
less dense fluid
upwards
Properties help
determines uses
a. Example: copper is a
good conductor of
electricity, used in
telephone wire and
power lines
d.
4.
**Chemical and Physical Change
1.
Chemical change: a
change that occurs
when a substance
changes composition
by forming one or
more new substances
a. The law of
conservation of
mass applies to all
chemical changes
2. Physical change: a change in the physical form
or properties of a substance that occurs without a
change in composition
a. The substance may look different, but the atoms
of the substance remain the same
b. Energy is always absorbed or release during a
physical change
c. Dissolving is a physical change