THE STATES OF MATTER
OBSERVED PROPERTIES OF MATTER
Matter
exists in
three distinct physical states:
GAS
LIQUID
and
PROPERTIES :
mass
density = ------------ = -----volume
V
shape
depends on the
physical state of matter
compressibility
SOLID
m
is the change
in volume of a sample resulting from a
pressure change acting on the sample.
thermal expansion
is the change
in volume of a sample resulting from a
change in temperature of the sample.
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
OBSERVED PROPERTIES OF MATTER
mass
density = -----------volume
m
------ = d
V
Material
Density
(gm/cm3)
Water at 4oC
Water at 20oC
Ice at 0oC
Gasoline
Mercury
Milk
Magnesium
Aluminum
Copper
Gold
Air
Carbon dioxide
Carbon monoxide
Hydrogen
Helium
Nitrogen
1.0000
0.998
0.92
0.70
13.6
1.03
1.7
2.7
8.3-9.0
19.3
0.001293
0.001977
0.00125
0.00009
0.000178
0.001251
golf balls / ping-pong balls
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
OBSERVED PROPERTIES OF MATTER
Solids retain the shape
regardless of the size or
shape of the container they
are in.
Liquids take the shape
of a container, but retain
their volume.
shape
depends on the
physical state of matter
Gases take the shape of a
container and fully fill the
(closed) container – i.e. have the
same volume as the inside of
the container.
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE KINETIC MOLECULAR THEORY OF MATTER
THE KINETIC MOLECULAR THEORY OF MATTER
A model or a theory used to explain the behavior of matter in its
various states.
THE POSTULATES OF THE KINETIC MOLECULAR THEORY
1.
2.
3.
4.
5.
Matter is composed of tiny particles called molecules.
The particles are in constant motion and therefore posses kinetic energy (KE).
The particles posses potential energy as a result of attracting or repelling each other.
The average particle speed increases as the temperature increases.
The particles transfer energy from one to another during collisions in which no net
energy is lost from the system.
1
KE = ---- mv2
2
Ek = kinetic energy
m = mass
v = velocity (of the particle)
Greek word κίνηση (kinesis) meaning "motion"
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE KINETIC MOLECULAR THEORY OF MATTER
THE KINETIC MOLECULAR THEORY OF MATTER
A model or a theory used to explain the behavior of matter in its
various states.
KINETIC ENERGY
The energy a particle has as
A result of its motion.
1
KE = ---- mv2
2
macromolecular examples:
gravitation; magnetic energy
El Camino College
Chemistry 21A
The force resulting from
particles motion; it is
associated with kinetic
energy.
COHESIVE FORCE
POTENTIAL ENERGY
The energy a particle has as
A result of attractive or
repulsive forces acting on it.
DISRUPTIVE FORCE
DEPENDS ON
The attractive force between
particles; it is associated
with potential energy.
THE STATE
OF MATTER
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE SOLID STATE
(DISRUPTIVE FORCES CAUSE
VIBRATIONAL MOTION)
THE LIQUID STATE
HIGH DENSITY
INDEFINITE SHAPE
DEFINITE SHAPE
SMALL COMPRESSIBILITY
VERY SMALL THERMAL EXPANSION
SMALL THERMAL EXPANSION
(ONLY
VIBRATIONAL
MOTION
INCREASES)
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE
LOW DENSITY
INDEFINITE SHAPE
HIGH COMPRESSIBILITY
MODERATE THERMAL EXPANSION
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE; THE GAS LAWS
Disruptive forces
overcome cohesive forces
between particles.
Nature of Gases - Properties
Gases are compressible.
Gases have low densities. (typically 2x10-3 g/mL)
Gases mix thoroughly.
Gases fill a container uniformly.
A gas exerts pressure uniformly on all sides of a container.
Gases have moderate thermal expansion.
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE; THE GAS LAWS
Kinetic Molecular
Theory
A gas is composed of very small particles
widely spaced.
A gas is composed mostly of empty space.
The molecules of a gas are in rapid,
random motion, colliding with
each other and the sides of the container.
Pressure is a result of these collisions.
All collisions involving gas molecules are elastic
(non-elastic - ball bouncing gets lower and lower each time).
Gas molecules have negligible attractive
(or repulsive) forces between them.
The temperature of a gas is related to the
average kinetic energy of the gas molecules.
(At the same temp. diff. gases have the same average KE).
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE; THE GAS LAWS
Physical Characteristics of Gases
physical characteristics
typical units
volume, V
liters (L)
pressure, p
atmosphere (1 atm=1.015x105N/m2)
temperature, T
Kelvin (K)
number of atoms or molecules, n
mole (1 mol=6.022x1023 atoms or molecules)
GAS LAW
is a mathematical relationship that describes
behavior of gases as they are mixed, subjected to
pressure or temperature changes, or allowed
to diffuse.
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE; THE GAS LAWS
PRESSURE = FORCE PER UNIT AREA
For gasses, usually related to atmospheric
pressure.
Schematic drawing of
a simple mercury
barometer with vertical
mercury column and
reservoir at base
Evangelista Torricelli
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE; THE GAS LAWS
mbar (atmospheric pressure
mmHg (blood pressure)
Pressure Units
pascal
(Pa)
bar
(bar)
technical
atmosphere
(at)
atmosphere
(atm)
torr
(Torr)
pound-force per
square inch
(psi)
1 Pa
≡ 1 N/m2
10−5
1.0197×10−5
9.8692×10−6
7.5006×10−3
145.04×10−6
1 bar
100,000
≡ 106 dyn/cm2
1.0197
0.98692
750.06
14.5037744
1 at
98,066.5
0.980665
≡ 1 kgf/cm2
0.96784
735.56
14.223
1
atm
101,325
1.01325
1.0332
≡ 1 atm
760
14.696
1
torr
133.322
1.3332×10−3
1.3595×10−3
1.3158×10−3
≡ 1 Torr;
≈ 1 mmHg
19.337×10−3
1 psi
6,894.76
68.948×10−3
70.307×10−3
68.046×10−3
51.715
≡ 1 lbf/in2
a.k.a. p.s.i.
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE; THE GAS LAWS
Temperature Conversion
°C
°F
°K
°C
°K
°F
=
=
=
=
=
=
(100/180) X (°F - 32)
(1.8 X °C) + 32
°C + 273.15
°K - 273.15
[(100/180) X (°F - 32)] + 273.15
[1.8 X (°K - 273.15)] + 32
ABSOLUTE ZERO
THE TEMPERATURE AT
WHICH ALL MOTION STOPS
0OK = -273.15OC
Celsius
Fahrenheit
Kelvin
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE; THE GAS LAWS
Boyle's Law:
P1V1 = P2V2 (= const.)
1662 Robert Boyle
Charles' Law:
V1/T1 = V2/T2 (= const.)
1787 Jacques Chales
1809 Joseph Gay-Lussac
Law of Gay-Lussac:
P1/T1 = P2/T2 (= const.)
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE; THE GAS LAWS
Boyle's Law:
P1V1 = P2V2 (= const.)
Charles' Law:
V1/T1 = V2/T2 (= const.)
Law of Gay-Lussac:
P1/T1 = P2/T2 (= const.)
1662 Robert Boyle
1787 Jacques Chales
1809 Joseph Gay-Lussac
PV
The COMBINED GAS LAW : ---------- =
T
El Camino College
Chemistry 21A
k
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE IDEAL GAS LAW
Boyle's Law:
P1V1 = P2V2 (= const.)
Charles' Law:
V1/T1 = V2/T2 (= const.)
Law of Gay-Lussac:
Avogadro's Law:
P1/T1 = P2/T2 (= const.)
The number of moles (n) is
equal to the mass (m )
divided by the molar mass (M):
V1/n1 = V2/n2 (= const.)
1811 Amadeo Avogadro
PV
The COMBINED GAS LAW : ---------- =
k
T
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE IDEAL GAS LAW
Boyle's Law:
P1V1 = P2V2 (= const.)
Charles' Law:
V1/T1 = V2/T2 (= const.)
Law of Gay-Lussac:
Avogadro's Law:
P1/T1 = P2/T2 (= const.)
V1/n1 = V2/n2 (= const.)
1811 Amadeo Avogadro
PV
The COMBINED GAS LAW : ---------- =
The number of moles (n) is
equal to the mass (m )
divided by the molar mass (M):
Equal volumes of different gases at the
same temperature and pressure contain
the same number of gas molecules.
k = nR
T
R = universal gas constant
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE IDEAL GAS LAW
PV
The COMBINED GAS LAW : ---------- =
k (= nR)
T
The number of moles (n) is
equal to the mass (m )
R = universal gas constant divided by the molar mass (M):
Ideal Gas Law:
PV = nRT
standard conditions
P = 1 atm
T = 273 K
STP (standard
temperature and pressure)
V = 22.4 L (volume of 1 mol of any gas at STP)
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE; THE GAS LAWS
R = V·P·T−1·n−1
El Camino College
Chemistry 21A
R = 0.0820574587 L·atm·K−1·mol−1
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE; THE GAS LAWS
R = V·P·T−1·n−1
8.314472 cm3·MPa·K−1·mol−1
8.314472 L·kPa·K−1·mol−1
8.314472 m3·Pa·K−1·mol−1
8.314472 × 107 erg·K−1·mol−1
83.14472 cm3·bar·mol−1·K−1
83.14472 L·mbar·K−1·mol−1
0.08314472 L·bar·K−1·mol−1
0.0820574587 L·atm·K−1·mol−1
8.20574587 × 10−5 m3·atm·K−1·mol−1
1.987 cal·K−1·mol−1
62.36367 L·mmHg·K−1·mol−1
62.36367 L·Torr·K−1·mol−1
El Camino College
Chemistry 21A
R = 0.0820574587 L·atm·K−1·mol−1
6.132440 lbf·ft·K−1·g-mol−1
6.132440 lbf·ft·K−1·g-mol−1
1545.349 lbf·ft·°R−1·lb-mol−1
10.73159 ft3·psi· °R−1·lb-mol−1
0.7302413 ft3·atm·°R−1·lb-mol−1
998.9701 ft3·mmHg·K−1·lb-mol−1
American units included
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE; THE GAS LAWS
Ideal gases do NOT exist. However, under normal conditions
(moderate temperatures and pressures) for the most gases
(such as monoatomic gases – noble gases and nonpolar
molecular gases – O2, N2, etc.) the Ideal Gas Law can be
applied successfully.
PV = nRT
m
PV = -----RT
M
mRT
M = ------PV
molecular weight
1801 John Dalton
Dalton’s Law of Partial Pressures
the total pressure of a gas in a system is the sum
of the partial pressures of each component gas.
PT = P1 + P2 + P3 + ....
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
THE GASEOUS STATE; THE GAS LAWS
Scuba Diving
Our respiratory systems are designed to maintain the proper
oxygen concentration in the blood when the partial pressure of O2 is 0.21
atm, its normal sea-level value.
Below the water surface, the pressure increases by 1 atm for each 10.3
m increase in depth; thus a scuba diver at 10.3 m experiences a total of 2
atm pressure pressing on the body. In order to prevent the lungs from
collapsing, the air the diver breathes should also be at about the same
pressure.
But at a total pressure of 2 atm, the partial pressure of O2 in ordinary air
would be 0.42 atm; at a depth of 10 m ft (about 33 ft), the O2 pressure of
0.4 atm would be far too high for health. For this reason, the air mixture in
the pressurized tanks that scuba divers wear must contain a smaller
fraction of O2. This can be achieved most simply by raising the nitrogen
content, but high partial pressures of N2 can also be dangerous, resulting
in a condition known as nitrogen narcosis. The preferred diluting agent for
sustained deep diving is helium, which has very little tendency to dissolve
in the blood even at high pressures.
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
CHANGES IN STATE
A change of state is the conversion of a
substance from one physical form to another.
All changes of state are physical changes.
In a physical change the identity of the substance does
not change.
Four changes of state
freezing
endothermic
melting
vaporization
condensation
exothermic
sublimation
crystallization
Which has more energy – gas or liquid?
Which has more energy – liquid or solid?
Which has more energy – gas or solid?
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
CHANGES IN STATE
A change of state is the conversion of a
substance from one physical form to another.
All changes of state are physical changes.
In a physical change the identity of the substance does
not change.
Four changes of state
freezing
endothermic
melting
vaporization
condensation
exothermic
sublimation
crystallization
Which has more energy – gas or liquid?
Which has more energy – liquid or solid?
Which has more energy – gas or solid?
El Camino College
Chemistry 21A
Endothermic – energy is absorbed therefore the
particles move faster, breaking the bonds
Exothermic – energy is given off therefore
particles move slower making them lock into place
Dr. Dragan Marinkovic
THE STATES OF MATTER
CHANGES IN STATE
vaporization
endothermic
Change from liquid to gas
2 types
evaporation - occurs at the surface of a
liquid below its boiling point
Boiling – occurs throughout a liquid
when the temperature is at the
boiling point
El Camino College
Chemistry 21A
Condensation – an exotermic
process in which a gas or vapor
is changed to a liquid or a solid.
Dr. Dragan Marinkovic
THE STATES OF MATTER
CHANGES IN STATE
Vapor pressure
The pressure exerted by vapor
hat is in equilibrium with liquid.
It depends on the nature of the
liquid (molecular polarity, mass,
etc.) and the temperature of the
liquid.
When vapor pressure
reaches 760 Torr (1 atm)
the liquid starts to boil,
i.e. the liquid reached
the boiling point.
Normal or standard boiling point
water vapor presure
is the temperature at which the vapor
pressure of a liquid is equal to
1 atm (760 Torr).
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
CHANGES IN STATE
Boiling Point Of Water
Altitude in
Meters
Degrees F.
Degrees C.
0
0
212.0
100.0
500
152
211.0
99.4
1000
305
210.0
98.9
2000
610
208.2
97.9
3000
914
206.2
96.8
4000
1219
204.4
95.8
5000
1524
202.6
94.8
6000
1829
200.7
93.7
7000
2134
198.7
92.6
8000
2438
196.9
91.6
10,000
3048
194.0
90.0
12,500
3810
189.8
87.7
14,000
4267
187.3
86.3
Altitude in
Feet
A standard pressure cooker operating at
820 Torr (1.078 atm), rises the boiling point
of water to 250°F (121°C) at sea level. At
240°F (116oC, which corresponds to only
1.06 atm = 604 Torr) the cooking times
must be increased by 33% in comparison
to the standard 820 Torr.
For every 1000 ft above 2000 ft elevation,
increase the cooking time by 5%.
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
CHANGES IN STATE
Sublimation
Change from solid directly to gas.
The change of energy is endothermic.
Melting point
Decomposition
The temperature at which a
solid changes to a liquid;
the solid and liquid have
same vapor pressure.
a change in chemical
composition that can
result from heating.
Melting
Change from solid to liquid
Melting points can be used to identify a
substance. Melting point is a characteristic
property. The change of energy is
endothermic because it absorbs energy thus
the particles move away from one another
Total added heat (cal)
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
CHANGES IN STATE
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
CHANGES IN STATE
The specific heat is the
amount of heat per unit mass
required to raise the temperature
by one degree Celsius
Specific heats and molar heat capacities
for various substances at 20oC
Substance
c in J/gm K
c in cal/gm K or
Btu/lb F
Molar C
J/mol K
Aluminum
0.900
0.215
24.3
Bismuth
0.123
0.0294
25.7
Copper
0.386
0.0923
24.5
Brass
0.380
0.092
...
Gold
0.126
0.0301
25.6
Lead
0.128
0.0305
26.4
Silver
0.233
0.0558
24.9
Tungsten
0.134
0.0321
24.8
Zinc
0.387
0.0925
25.2
Mercury
0.140
0.033
28.3
2.4
0.58
111
Water
4.186
1.00
75.2
Ice (-10 C)
2.05
0.49
36.9
Granite
.790
0.19
...
Glass
.84
0.20
...
Alcohol(ethyl)
El Camino College
Chemistry 21A
Dr. Dragan Marinkovic
THE STATES OF MATTER
Heat of Fusion
CHANGES IN STATE
The energy required to change a gram
of a substance from the solid to
the liquid state without changing its
temperature is commonly called it's
"heat of fusion". This energy breaks
down the solid bonds, but leaves a
significant amount of energy associated
with the intermolecular forces of the
liquid state.
El Camino College
Chemistry 21A
Heat of Vaporization
The energy required to change a gram of a
liquid into the gaseous state at the boiling
point is called the "heat of vaporization".
This energy breaks down the intermolecular
attractive forces, and also must provide the
energy necessary to expand the gas (the PDV
work). For an ideal gas , there is no longer any
potential energy associated with intermolecular
forces. So the internal energy is entirely in the
molecular kinetic energy.
Dr. Dragan Marinkovic