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SOLIDS, LIQUIDS,
AND GASES
CHAPTER 14
M AT T E R A N D T H E R M A L E N E RG Y
SECTION ONE
• Kinetic Theory – an explanation of how the particles in gases
behave.
 All matter is composed of tiny particles (atoms, molecules, and
ions)
 These particles are in constant, random motion
 The particles collide with each other and with the walls of any
container where they are held
 The amount of energy that particles lose from these collisions is
negligible
LIQUIDS
 Like gases, particles in a liquid state are constantly moving.,
although they don’t move as quickly
 So particles in liquids have less kinetic energy than those in gas
state
 Because of less kinetic energy, the particles stick closer together,
thus enabling liquids to flow; why water can be poured
 Also why liquids have definite volume
SOLIDS
 Unlike gases or liquids, solids have a definite volume and shape
 Particles are packed together
 Still particles are moving so have even less kinetic energy than
liquids.
 Many are crystalline – particles have a geometric arrangement
CHANGES OF STATE
THERMAL EXPANSION
 Thermal expansion is the tendency of matter to change in volume in
response to a change in temperature.[1]
 When a substance is heated, its particles begin moving more and thus usually
maintain a greater average separation. Materials which contract with increasing
temperature are unusual; this effect is limited in size, and only occurs within
limited temperature ranges). The degree of expansion divided by the change in
temperature is called the material's coefficient of thermal expansion and
generally varies with temperature.
PROPERTIES OF FLUIDS
SECTION TWO
Archimedes Principle
Pascal’s Principle
Bernoulli’s Principle
ARCHIMEDES PRINCIPLE
Buoyancy – the ability of a fluid, liquid or gas, to exert
an upward force on an object immersed in it.
In the third century, Greek mathematician, Archimedes,
found the buoyant force on an object is equal to the
weight of the fluid displaced by the object.
BUOYANCY
ARCHIMEDES PRINCIPLE
PASCAL’S PRINCIPLE
 or the principle of transmission of fluid-pressure is a
principle in fluid mechanics that states that pressure exerted
anywhere in a confined incompressible fluid is transmitted
equally in all directions throughout the Fluid.
 The law was established be French mathematician,
Blaise Pascal
PASCAL’S PRINCIPLE
BERNOULLI’S PRINCIPLE
 Bernoulli's principle states an increase in the speed of
the fluid occurs simultaneously with a decrease in
pressure
 Bernoulli's principle is named after the Swiss scientist
Daniel Bernoulli, who published his principle in his book
BERNOULLI’S PRINCIPLE
VISCOSITY
Resistance of a fluid to flow
Example:
Water flows easily because it has low
viscosity
(oil/syrup bottles)
BEHAVIOR OF GASES
SECTION THREE
Boyle’s Law
Charles’ Law
Other
Temperature in the gas laws must be in
Kelvin, K
BOYLE’S LAW
Robert Boyle, a British scientist, describes the relationship
between gas pressure and volume.
If you decrease the volume of a
container of gas and hold the temperature
constant, the pressure will increase.
BOYLE’S LAW EQUATION
Initial pressure * initial volume = final pressure * final volume
PiVi = Pf Vf
 Page 449 Example problem 3
Practice Problem 20 & 21
CHARLES’ LAW
The relationship between temperature and volume was
discovered by French scientist, Jacques Charles.
The volume of a gas increases with the increase of
temperature, as long as the pressure does NOT
change.
CHARLES’ LAW EQUATION
initial volume = final volume
initial
temperature
Vi
Ti
final
temperature
=
Vf
Tf
Charles’ Law example problem
Page 451
Practice Problems
22 & 23
KEPPLE’S LAW
P1
P2
T1
T2
Gay-Lussac or Avogadro’s
IDEAL GAS LAW
PV=nRT
P = pressure
V = volume
n = moles
R = gas law constant
T = temperature in Kelvin, K
R VALUES FOR IDEAL GAS
LAW
0.08206 L*atm/mol*K
 8.314 L*KPa/mol*K
 R value depends on units used for
pressure