Chapter 3 States of Matter
Section 1
Matter and Energy
Kinetic Theory of Matter
• Matter is made of atoms and molecules.
• Atoms and molecules act like tiny
particles.
• They are always in motion.
• The higher the temperature of the
substance, the faster the particles move.
• At the same temperature, the more
massive particles move slower that the
less massive ones.
• Example: hot tea cooking
States of Matter
• The state of matter is the physical form of
the matter.
• This form is determined partly by how the
substance’s particles move.
• Matter can be classified by determining
whether the shape and volume are definite
or variable.
• Most matter found on Earth is either a
solid, liquid, or gas.
States of Matter
•
•
•
•
•
Solid
Liquid
Gas
Plasma
Bose-Einsteinium condensate
Solids
• Particles vibrate in place (Brownian
movement)
• Structure of solids are rigid and cannot
easily change shape.
• Particles are held closely together by
strong attractions which between the
particles which cause solids to have a
definite shape and volume.
Liquid
• Particles are closely packed but can
slide past one another and move more
rapidly than in a solid in order to
overcome attractive force.
• Liquids flow freely (is a fluid)
• Take the shape of the container
• Do not change volume.
• Particles are close together and in
contact.
Gas
•
•
•
•
•
•
•
Particles are in constant motion.
Do not usually stick together
Change volume and shape
Are fluids because they can flow.
Are usually compressed (pushed together)
Gases expand to fill the empty space.
Example: perfume
Plasma
•
•
•
•
•
•
Most common state (99% of matter)
No definite shape or volume
No definite shape or volume
Particles are electrically charged (ionized)
Conducts electric current
Examples: in lightning, fire, aurora
borealis, sun, other stars, artifically in
fluorescent lights
Kinetic energy
• Energy of motion
• Energy- ability to do work; ability to
change or move matter
• Since all matter is made up of tiny
particles, (atoms, molecules) that are
constantly in motion, all matter has kinetic
energy.
Temperature
• Measure of average kinetic energy of
particles in an object.
• Particles of matter are constantly moving.
• Do not move at the same speed.
• Some particles have more kinetic energy
than others.
• The higher the temperature, the more
kinetic energy.
Thermal Energy
• Depends on particle speed and number of
particles.
• Does not depend on amount of substance
• Thermal energy= total kinetic energy of
particles making up the substance
• Total kinetic energy depends on the
number of the particles as well as the
speed of particles.
Section 2
Changes of State
• The identity of substance does not change
during a change of state
• The energy of a substance does change
• Add energy particles move faster
• Remove energy particles slow down
• Heat and energy can cause changes of state
Melting
• Heat solid, transfer energy to particles,
thus they vibrate faster as they gain
energy.
• They break their fixed position and melt.
• Melting point=the temperature at which a
substance changes from a solid to a liquid.
• Melting point depends on pressure.
Evaporation
• Change of a substance from a liquid to gas
• Boiling is evaporation occurring throughout a
liquid at a certain temperature and pressure.
• Boiling point= the temperature at which a liquid
boils.
• A decrease in pressure lowers the boiling point
Sublimation
• Solid changing directly to a gas without
going through the liquid state.
• Example: dry ice
• Melting, evaporation, sublimation all
require energy.
Condensation
• Change of state from a gas to a liquid
• Energy is released because gas particles
clump together and they slow down.
• Example: breathing on a cold day
• Condensation point=the temperature at
which a gas becomes a liquid
• Example: drops of water on a cold glass of
a liquid
Freezing Point
• Temperature at which a liquid changes to a solid
• Energy is released.
• FREEZING AND MELTING OCCUR AT THE
SAME TEMPERATURE!
• Water freezes at the same temperature at which
it melts. O degrees Celsius
• For freezing to occur, the attractions between
the particles must be greater than their motion.
• Ex: Ammonia=-77.7oC and Magnesium=650oC
Temperature
• Temperature is constant during change of
state.
• When a substance loses or gains energy,
its temperature changes or its state
changes.
Temperature (continued)
• Temperature does not change during a
change of state.
• Example: If we add energy to ice at O
degrees C, the temperature will NOT rise
until all of the ice has melted.
Conservation of Mass and Energy
• Mass is conserved for all physical and chemical
changes.
• Energy can change forms but the total amount of
energy before and after a change is the same.
• The amount of energy in a substance can
change but it must come from somewhere else.
Law of Conservation of Matter and
Energy
• Matter and energy are both conserved.
• Neither matter or energy can be created or
destroyed.
Law of Conservation of Mass
• Mass can not be created or destroyed.
• Mass before change= Mass after change
• Mass of reactants = mass of products
• Match + oxygen = ash, smoke, gases
Law of Conservation of Energy
• Energy can not be created or destroyed.
Energy before change =energy after change
Section 3 Fluids
• Liquids and gases are fluids.
• Fluids exert pressure evenly in all
directions.
• Pressure= amount of force exerted on a
given area of surface.
• Example: air up bicycle tire
Pressure
• P=F/A
• Pressure = force divided by area
• Unit of pressure is Pascal
• SI unit of force is the newton.
• One Pascal=force of 1 newton exerted over an
area of 1 square meter or 1N/m2
Buoyant Force
• A buoyant force pushes a duck up if you
push a duck down.
• All fluids exert an upward buoyant force.
Archimedes’ Principle
• Used to find buoyant force
• The buoyant force on an object in a fluid is an
upward force equal to the weight of the fluid that
the object displaces.
• You can determine if an object will float or sink
by comparing the buoyant force on the object
with the object’s weight.
• See example of sea gull on page 90
Density
• Can determine if an object will float or
sink by comparing densities.
• More dense objects sink.
• Ex: Helium less dense than air so it floats.
• Steel is almost 8 times denser than water.
Density (continued)
• Ships float and carry cargo and still float.
• Shape is the answer. Boats have a hollow
hull. The hollow shape of the boat allows
it to have the same amount of steel but the
density is decreased by the hollow shape.
Water is then denser than the boat and the
boat floats.
Pascal’s Principle
• A change in pressure at any point in an
enclosed fluid will be transmitted equally to
all parts of the fluid.
• Ex: toothpaste tube
• If the pressure in a container is increased
at any point, the pressure increases at all
points by the same amount.
Pascal’s Principle (continued)
• P1=P2 because P=F/A or
• F1/A1 = F2/A2
• Hydraulic devices use this principle.
• Hydraulic devices use liquids to transmit
pressure form 1 point to another. Liquids can not
be compressed into a much smaller space.
continued
• Hydraulic devices multiply forces.
• Fluid is usually oil.
Fluids in Motion
• Fluids move faster through small areas
than through larger areas, if the overall
flow rate remains constant. (garden hose)
• Fluids also vary in the rate at which they
flow.
Viscosity
• Viscosity- a liquid’s resistance to flow.
• The stronger the attraction between a
liquid’s particles, the more viscous the
liquid is. Ex: Honey, water
Bernoulli’s Principle
• States that as the speed of a moving fluid
increases, the pressure of the moving fluid
decreases.
• See example of leaf on page 94
Section 4
Behavior of Gases
•
•
•
•
•
•
•
•
Fluids
Move rapidly in all directions
Expand to fill containers they are in
Spread out easily
Mix with one another
Low density
Are compressible
Mostly empty space
Gases and Pressure
• Gases under pressure are dangerous.
• Gases under pressure rush out if given an
escape route. (balloon)
• Must be handled very carefully.
Gas Laws
• Volume of a gas is the same as the
volume of the container it is in
• Gases behave differently than solids and
liquids.
• Gas laws describe how the behavior of a
gas in affected by pressure, volume, and
temperature.
• Can use gas laws to predict the behavior
of gases in specific situations.
Boyle’s Law
• Relates pressure of a gas to its volume
• For a fixed amount of gas at a constant
temperature, the volume of a gas increases as
the gas’s pressure decreases.
• Also, the volume of a gas decreases as the
gas’s pressure increases.
• Temperature does not change.
• One increases when the other decreases.
Boyle’s Law (continued)
• Pressure1(volume1)=Pressure2(volume2)
or
P1V1 = P2V2
1 is initial volume and pressure and 2 is final
volume and pressure
Gay-Lussac’s Law
• Relates gas pressure to temperature at
constant volume
• Pressure= result of collision of gas
molecules against wall of container
• Temperature increases, motion of particles
increases meaning kinetic energy
increases meaning energy and frequency
of collisions increases.
Gay-Lussac’s Law (continued)
• For a fixed quantity of gas at constant
volume, the pressure as the temperature
increases.
• The pressure of a gas increases as the
temperature increases, if the volume of the
gas does not change. The pressure
decreases as the temperature decreases.
• Example: tires in cold weather lose air???
• Pressurized containers like hair spray
Charles’ Law
• Relates temperature to volume
• For a fixed amount of gas at a constant
pressure, the volume of the gas increases
as the gas’s temperature increases and
the volume of the gas decreases as the
gas’s temperature decreases.
• Example: balloon in heat, balloon in cold