Ch. 16 - Solids, Liquids, & Gases
I. States of Matter–Kinetic Molecular Theory–Four States of Matter–Thermal Expansion
MATTER
A. Kinetic Molecular Theory
• KMT
– Tiny, constantly moving particles make up all matter.
– The kinetic energy (motion) of these particles increases as temperature increases.
– Temperature = AVERAGE kinetic energy of the particles in a system.
– Heat = TOTAL kinetic energy of the particles.
B. Four States of Matter
• Solids– low KE - particles vibrate but can’t
move around– definite shape & volume– crystalline - repeating geometric
pattern (MOST solids)– amorphous - no pattern (e.g. glass,
wax, obsidian) – it was frozen too fast to organize into crystals
B. Four States of Matter
• Liquids– higher KE - particles can move
around but are still close together– indefinite shape– definite volume– Viscosity – resistance to flow.
Motor oil, syrup have high viscosity; water, gasoline lower viscosity
Heating the liquid reduces viscocity (warming syrup makes it flow easier)
B. Four States of Matter
• Gases– high KE (moving very fast) - particles
can separate and move throughout container (99% empty space)
– indefinite shape & volume
B. Four States of Matter
• Plasma– very high KE - particles collide with enough
energy to break into charged particles (+/-)– gas-like, indefinite
shape & volume– Stars (Sun), fluorescent
light bulbs, TV tubes,
lightning
Most common state in the
universe
C. Thermal Expansion• Most matter expands when
heated & contracts when cooled.
• Temp causes KE. Particles collide with more force & spread out.
• EX: thermostats (bimetallic strip) – two different metals, one contracts/expands more than the other.
Solid expansion, cont.
• Expansion joints in bridges, concrete,etc.
Expansion of liquids
• Alcohol or mercury in a (old style) thermometer expands with an increase in temperature.
Gas expansion
• Gases expand/contract the most of the states of matter.
• EX. Hot-air balloons. Air expands, becomes less dense, rises.
Ch. 16 - Solids, Liquids, & Gases
II. Changes in State–Phase Changes–Heating Curves
MATTER
A. Phase Changes
• Melting– solid to liquid
• Freezing– liquid to solid
melting point = freezing point
** The temperature of a substance CAN NOT change during a phase change.
• Vaporization (two types)
1. boiling - liquid to gas at the boiling point & throughout the liquid
2. evaporation - liquid to gas below the boiling point, but only at the surface
• Sublimation– solid to gas
without becoming a liquid in between
– EX: dry ice, freeze drying, iodine
• Condensationgas to liquid
A. Phase Changes
B. Heating Curves
• Kinetic Energy– motion of particles– related to temperature
• Potential Energy– space between particles– related to phase changes
B. Heating Curves
Solid - KE
Melting - PE
Liquid - KE Boiling - PE
Gas - KE
B. Heating Curves
• Heat of Fusion– energy required to change from solid to
liquid– some attractive forces are broken
B. Heating Curves
• Heat of Vaporization– energy required to change from liquid
to gas– all attractive forces are broken– EX: steam burns, sweating, and… the
drinking bird
HEATING CURVE
Ch. 16 - Solids, Liquids, & Gases
III. Behavior of Gases–Pressure–Boyle’s Law–Charles’ Law
MATTER
A. Pressure
area
forcepressure
Which shoes create the most pressure?
A. Pressure
• Key Units at Sea Level
101.3 kPa (kilopascal)
1 atm
760 mm Hg
14.7 psi
2m
NkPa
A. Pressure
Barometer
Atm
osph
eric
Pre
ssur
e
Manometer
Con
tain
ed P
ress
ure
A. Pressure
• Effect on Boiling Point– When atmospheric pressure
decreases, the boiling point of a liquid decreases.
– EX: high altitude cooking– Denver is 1 mile above sea level &
water boils at 95o C; – on Mt. Everest (5.5 miles high) 71o C
Converting temperature units
• K = 0C + 273 0C = K – 273• What is the kelvin temperature of
20oC?
20 oC ___________ = • What is 20 K in celcius?
20 K _________ =
Boyle’s Law (temp constant)
• Pressure and volume are inversely proportional. i.e. if one goes up the other goes down.
• A decrease in the volume of gas will result in an increase in pressure
• An increase in the volume of gas will result in a decrease in pressure
V1P1 = V2P2
P
V
PV = kB
INVERSE
B. Boyle’s Law
V1=20 & P1 = 30P2 = 120 V2= ?
V1 P1 = V2 P2
(20)(30) = (V2)(120)
600 = (V2)(120)600 = V2
120
5 = V2
V1=50 & P1 = 30V2 = 120
V1 P1 = V2 P2
(50)(30) = (120)(P2)
1500 = (120) (P2)
12.5 = P2
Charles’s Law(pressure constant)
• Volume of a gas increases with increasing temperature
• Volume of a gas decreases with decreasing temperature
V1 = V2
T1 T2
kT
VV
T
C. Charles’ Law
• When the temperature of a gas increases, its volume also increases (at constant pressure).
DIRECT
C. Charles’ Law
C. Charles’ Law
• Absolute Zero - Temp at which...– the volume of a gas would equal zero.– all particle motion would stop.
-273°Cor
0 K
Example #1
V1=20, T1 = 30, & T2 = 120
V1 = V2
T1 T2
20 = V2
30 120
2/3 * 120 = V2
80 = V2
Example #2
V1=120, T1 = 30, & V2 = 300
V1 = V2
T1 T2
120 = 300 30 T2
120 * T2 = 300 * 30
120 * T2 = 9000
T2 = 75
Relating to Life
Principle – Use• Boyles (temperature constant)
–Squeezing a balloon• Charles (pressure constant)
–Why balloons decrease in size when kept in a cold room
–Reason for statement on hair spray: “keep away from heat, contents under pressure”
Problems
# V1 V2 T1 T2
5 38 138 ? 69
6 ? 15 20 45
7 30 ? 6 13
8 76 17 38 ?
Charles Law
Boyles Law# V1 V2 P1 P2
1 30 15 ? 7
2 40 15 3 ?
3 ? 20 30 60
4 10 ? 34 102
Answers
# V1 V2 T1 T2
5 38 138 19 69
6 6.67 15 20 45
7 30 65 6 13
8 76 17 38 8.5
Charles Law
Boyles Law# V1 V2 P1 P2
1 30 15 3.5 7
2 40 15 3 8
3 40 20 30 60
4 10 2.35 34 102
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