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