Chapter 16Solids, Liquids, Gases

Section 1 Kinetic TheoryPages 476-484

Kinetic Theory of MatterPage 476

• All matter is composed of small particles– Atoms, molecules, ions

• These particles are in constant, random motion

• These particles are constantly colliding with each other and with the walls of the container.

Thermal Energy (P477)

• Particles in matter are in constant motion– Solids- the particles vibrate– Liquids – held loosely together– Gases – move about independently

• Kinetic Energy due to motion of the particles• Potential Energy due to the attractive forces

between the particles

Temperature• Temperature tells how hot or cold an object is• Temperature is a measure of the average

kinetic energy of the particles of a substance• Ice molecules are moving slower than

molecules of liquid water which are moving slower than molecules of steam.

• Absolute zero is the temperature at which no thermal energy can be removed from an object.

• - 273 oC also known as 0 K

Thermometers

Fahrenheit Celsius or centigrade Kelvin

Freezing temp of water

Boiling temp of water212o 100o 373o

32o 0o 273o

-273o 0o

-458o

States of Matter or Phases of Matter (P477-479)

• Solid– Has definite shape and volume– Particles are packed together tightly– Particles vibrate but are bond together

• Liquid– Has definite volume but takes the shape of the container.– Particles are able to move more freely– Have enough kinetic energy to break the forces that hold them

together and flow.

• Gas – No definite shape nor definite volume– Particles are far apart and weak attraction between particles

Phase ChangeSolid/Liquid (P478)

• Melting or freezing– Change from solid to liquid or liquid to solid– Change from solid to liquid requires energy to

break the forces of attraction between the particles.

– Change from liquid to solid requires removal of energy

Phase Change (cont)Solid/Liquid

– Most substance have a temperature at which it melts or freezes.

– This is called the melting point.– At that temperature if the substance looses heat it

freezes and if it gains heat it melts.– The energy required to melt or freeze a substance

is called the heat of fusion.

Phase ChangeLiquid/Vapor (gas)

• Vaporization (boiling) changing from liquid to vapor.

• Condensation changing from vapor to liquid

Phase Change (P479)Liquid/Vapor (cont)

– Boiling point is the temperature at which a substance changes from liquid to vapor or from vapor to liquid

– Heat of vaporization is the quantity of heat that is needed to break the attraction between particles and change a substance from liquid to gas.

– This is also the quantity of heat that must be removed from a substance to change from vapor to liquid.

Heating CurveWater (p480)

Quantity of Heat kJ10 20 30 40 50 60 70 80 90 100 110

-20

0

20

40

60

80

100

120

140

solid

liquid

Gas (vapor)

Boiling Point

Melting Point Phase Change

Phase Change

Review

• Phase or State- solid, liquid, gas• Phase Change

– Temperature – melting or boiling point– Heat – heat of fusion or heat of vaporization

• Heating Curves– Interpreting

Heat of Fusion Heat of Vaporization

• Often called Latent heat of Fusion and Latent heat of vaporization

• Water-• Specific heat 4184 Joules/kg oC• Heat of fusion 330,000 Joules/kilogram• Heat of Vaporization 2,260,000 Joules/kilogram

Heating CurveNot Water

Quantity of Heat kJ

1 2 3 0

20

40

60

80100

120140

solid

liquid

Gas (vapor)Boiling Point

Melting Point

Phase Change

Phase Change

160

180

200

0 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Phase ChangeSolid/Vapor

• Under some circumstances phase change skips the liquid phase.

• Sublimation Phase changes from solid to gas

• Deposition Phase changes from gas to solid

Plasma (P480)• Matter consisting of positively and negatively

charged particles• Particles are so hot (high kinetic energy) that when

they collide, electrons are knocked loose from the atoms forming ions (+ and – charged particles).

• Found in stars including the sun• Most abundant state (phase) in the universe, but

rarely seen on earth.• Also in lightening bolts, neon and fluorescent lights.

Solid or Liquid (P482& 483)• Amorphous solids

– Some materials do not change phase at a definite temperature.

– These materials gradually turn from solid to liquid over a range of temperatures.

– Lack the highly ordered structure of crystalline solids– Glass and plastics

• Liquid Crystals– Do not lose their crystal characteristics as they turn

from solid to liquid.– Liquid form maintains a crystal structure.

Thermal Expansion (P481)• Thermal Expansion is an increase in the size of

an object when the temperature increases.• Kinetic Theory Explanation

– Particles move faster the hotter they are– Fast moving particles move farther apart

• Thermal Contraction is a decrease in the size of an object when the temperature decreases– Particles move slower when cooled– Slower moving particles move closer together

Importance of Thermal Expansion

• Must design mechanical things for this expansion.– Bridge expansion joints-Page 499– Concrete expansion joints

• Basic Design Principle of the Thermometer• Hot air balloons (p481)- air expands and is not

as dense. Lighter air floats in denser air

The Strange Case of WaterWater is unusual, the solid phase is less dense

than the liquid phase. Ice Floats in water.

OHH

_

+ +

Liquid and Solid Water

Wonderful Water

• If ice did not float then lakes and ponds would freeze from the bottom and kill all the living things in the lake or pond.

• Water expands when frozen so water in cracks in rocks expand and cracks the rocks.

• Universal solvent - many things dissolve in water.

• Stores a lot of heat– Heating and cooling applications

Chapter 16Section 2 Properties of Fluids

Read Pages 485-489

Buoyancy• Buoyancy is the ability of a fluid (liquid or gas)

to exert an upward force on an object immersed in it.

• Archimedes Principle (3rd century BC Greek)• The buoyant force on an object is equal to the

weight of the fluid displaced by the object.• An object will float (in water) if the weight of

the fluid (water) displaced is greater than the weight of the object.

• An object will float in a fluid if the density of the object is less than the density of the fluid.

Buoyant Force (P485)

Buoyant Force = weight of fluid displacedWeight of Object

Weight of Object = < Buoyant Force then the object floats

Bouyancy

• Weight of Object = < Buoyant Force then the object floats• Buoyant Force= Weight of Fluid Displaced • Weight of Object = < Weight of Fluid, the object floats

• Weight = mg• mg of object =< mg of fluid• ρ = m/V m= ρ V• ρ Vg of object =< ρ Vg of fluid• V of object = V of fluid• ρ of object =< ρ of fluid the object floats

Why do Objects Float

• An object will float (in water) if the density of the object is less than the density of water.

<Mass of ObjectVolume of Object

__________mass of water_________ Volume of water = volume of object

ρ = m/V m= ρ V

Pascal’s Principle

• Pressure is force exerted per unit area• P = Force/Area (N/m2 called a Pascal)• At any point in a fluid the pressure is equal in

all directions.• Pascal discovered that pressure applied to a

fluid is transmitted (undiminished, it is the same) through out the fluid.

Practice Problem P487

• A hydraulic lift (press) is used to lift a heavy machine that is pushing down on a 2.8 m2 piston (A1) with a force (F1) of 3,700 N. What force (F2) needs to be exerted on a 0.072 m2 piston (A2) to lift the machine?

F1_A1

F2_A2

P1 = P2

=

Properties of Fluids (1)• Archimedes Principle (3rd century BC Greek)

– Buoyancy is the ability of a fluid (liquid or gas) to exert an upward force on an object immersed in it.

– The buoyant force on an object is equal to the weight of the fluid displaced by the object.

– An object will float (in water) if the weight of the fluid (water) displaced is greater than the weight of the object.

Properties of Fluids (2)• Pascal’s Principle

– P = Force/Area (N/m2 called a Pascal)– Pascal discovered that pressure applied to a fluid

is transmitted (undiminished, it is the same) through out the fluid.

F1_A1

F2_A2

P1 = P2

=

Hydraulic Press P487

F1

F2

A1 A2

P1 =F1_A1

P2 =F2_A2

Assignment• Page 487 Practice Problem (Challenge)• A large crate weighing 2,500N sits on a piston

with an area of 25 m2. what force must be applied to the other piston with an area of 5.0 m2 in order to lift the crate? – Given:– Asked:– Formula:– Substitute– Answer with units

Warm Up Assignment

• A large crate weighing 1,200N sits on a piston with an area of 10 m2. a force of 50N is applied to the other piston to lift the crate, what is the area of the other piston? – Given:– Asked:– Formula:– Substitute– Answer with units

Schedule• Thursday 12/5 Bernoulli’s Principle, Hydraulic Jack Problems • Friday 12/6 Heat of Fusion Lab• Monday 12/9 Symposium• Tuesday 12/10 Discuss Lab/ Gas Laws• Wednesday 12/11 Gas Laws• Thursday 12/12 Gas Laws Problems• Friday 12/13 Charles Law Lab• Monday 12/16 NTWS• Tuesday 12/17 Chapter Review 1-16, Problem 22, 23,24 • Wednesday 12/18 Test Section 1-2

Bernoulli’s Principle • As the velocity of a fluid increases, the pressure of the fluid decreases. • This makes the shower curtain blow into the tub.• This makes airplanes fly.

Viscosity

• The resistance to flow by a fluid is called Viscosity. • Water is low viscosity• Cold syrup is high viscosity

• “Slow as molasses in January”

• 10W30 motor oil – this is the viscosity.

Chapter 16Section 3

Behavior of Gases

Read Pages 490-495

Review• States or Phases of Matter

– Solid, Liquid, Gas

• Kinetic Theory– Particles in constant random motion

• Change of Phase– Solid to Liquid, Liquid to Solid– Liquid to gas, gas to liquid

• Properties of Fluids– Buoyancy, Archimedes’ Principle, Pascal’s

Principle, Bernoulli’s Principle, Viscosity

Behavior of Gases• Pressure= Force per unit area P= F/A

– Newtons/Square Meter = Pascal• Volume

– m3 (very large), cm3 = 1 mL (very small)– Liter (L), 1000 mL = 1000 cm3

• Density = Mass/Volume• Atmospheric Pressure

– Pascal is very small measure– kPa for kiloPascals = 1000 Pa = 1000N/m2

– 1 atmosphere=101.3 kPa=101,300 Pa = 101,300 N/m2

Boyle’s Law

• Relationship between Volume and Pressure• Keeping number of particles and temperature

constant• Pressure• Temperature• Volume• number of particles

Boyle’s Law• Kinetic Theory

– Particles striking the walls of the container produces pressure – force against an area of the wall

• Decrease the size of the container then the particles strike more often – Increases Pressure

• Increase the size of the container then the particles strike less often– Decreases Pressure

• Keeping Temperature and the number of particles constant.

Boyle’s Law Formula• P 1/V• P = k/V• P V = k• P1V1= P2V2

• Pressure Pa= Newtons/square meter or kPa = 1000 Newtons /square meter

• Volume– Liter – 1 mL = cm3

– 1 Liter = 1000 mL = 1000 cm3

Boyles Law Practice Problems

• A balloon has a volume of 25.0 L at a pressure of 101 kPa. What will the new volume be when the pressure drops to 20.0 kPa?

• A weather balloon has a volume of 200.0 L at a pressure of 101 kPa. At what pressure will the volume be 150.0 L?

Charles’s Law P494• If Pressure is kept constant• As the temperature rises, particles move

faster and move farther apart.• As temperature falls, particles move slower

and get closer together.• As temperature rises, volume rises and as

temperature falls, volume falls.• V= k T but T must be in Kelvin• K = oC + 273

Converting from Centigrade to Kelvin

K = oC + 273

• 100 oC = _______ K ?• 20 oC = _______ K ?• 55 oC = _______ K ?• - 30 oC = _______ K ?

Charles’s LawApplying math 6-7

V1

T1

V2

T2

=

Practice Problem (P495)What would be the resulting volume of a 2.0 L balloon at

25oC that is place in a container of ice water at 3.0 oCGiven:Asked:

Substitute:

Answer:

Charles’ Law Different Gases

Applying Math Page 495 Problems 6

• A helium balloon has a volume of 2.00 L at 101 kPa. As the balloon rises the pressure drops to 97.0kPa. What is the new volume?

• Given:• Asked:• Formula:• Substitute:• Answer:

Applying Math Page 495 Problems 7

• If a 5 L balloon at 25 oC is gently heated to 30oC , what new volume would the balloon have?

• Given:• Asked:• Formula:• Substitute:• Answer:

Gay-Lussac’s Law• Pressure-Temperature relationship• If volume is kept constant and the mass of gas is

kept constant…• As temperature increases, pressure increases• As temperature decreases, pressure decreases.• P= k T• Temperature must be in kelvin

PT

= kP1

T1

P2

T2

=

Sample Problem

• The gas in a container is at a pressure of 300 kPa• at 25 oC. Directions on the container warn the

user not to keep it in a place where the temperature exceeds 52 oC. What would the gas pressure in the container be at 52 oC?

Combined Gas Law

PV T

= k

P1V1

T1

P2V2

T2

=

PV = k T

Ideal Gas Law

• PV = nRT• P= pressure• V= volume• N = number of molecules• T = temperature• R= gas constant

Gas LawsVariable Boyle’s Charles’ Gay-Lussac’s Combined

# particles constant constant constant constant

Temperature Constant Vary Vary Vary

Volume Vary Vary Constant Vary

Pressure Vary Constant Vary Vary

Formula PV= k V=kT P=kT PV/T =k

Formula P1V1 = P2V2 V1/T1= V2/T2 P1/T1= P2/T2 P1V1/T1= P 2V2/T2

oC + 273 = K

Schedule• Page 487 PP Challenge + Board Problem • Page 493 PP+ Board Problem • Page 495 Applying Math 6-7+Board Problem• Practice Problems – Thursday 12/12• Lab – Friday 12/13• Practice Problems – Monday 12/16• Notetaking Work Sheet due Tuesday 12/17• Chapter Review Page 500-501: 1-15, 22-23-24

– Due Wednesday 12/18

• Test Thursday 12/19