Chapter 3Chapter 3

States of MatterStates of Matter

Section 1: Matter and EnergySection 1: Matter and Energy

Kinetic TheoryKinetic Theory All matter is made of atoms and molecules that All matter is made of atoms and molecules that

act like particlesact like particles The particles are always in The particles are always in motion, the higher , the higher

the temperature, the faster they movethe temperature, the faster they move More massive particles move slower than less More massive particles move slower than less

massivemassive

States of MatterParticlesParticles energyenergy shapeshape volumevolume

SolidsSolids

LiquidsLiquids

GasesGases

Plasma

44thth state of matter state of matter Most common in the universeMost common in the universe Found in stars and lightningFound in stars and lightning Electrically charged broken particlesElectrically charged broken particles

EnergyEnergy

Energy is conservedEnergy is conserved Temperature measures kinetic energyTemperature measures kinetic energy Phase changes occur when energy is Phase changes occur when energy is

absorbed or releasedabsorbed or released Absorb: vaporization, melting, sublimation: vaporization, melting, sublimation Release: freezing, condensationRelease: freezing, condensation

Section 2: FluidsSection 2: Fluids

Fluids are liquids and gasesFluids are liquids and gases

BuoyancyBuoyancy

Buoyant force: : the upward force that fluids exert on matterthe upward force that fluids exert on matter A result of pressure which is the amount of A result of pressure which is the amount of

force exerted on a given areaforce exerted on a given area Pressure increases as depth increasesPressure increases as depth increases Objects float in a liquid or gas when the Objects float in a liquid or gas when the

upward force is greater than the downward upward force is greater than the downward forceforce

Archimedes’ PrincipleArchimedes’ Principle

The buoyant force on an object is equal to the The buoyant force on an object is equal to the weight of the fluid that the object displacesweight of the fluid that the object displaces

And so, objects more And so, objects more dense than a fluid will than a fluid will sink and less dense will float.sink and less dense will float.

The shape of an object can change its The shape of an object can change its buoyancybuoyancy

Fluids and PressureFluids and Pressure Fluids exert pressureFluids exert pressure

Pressure = Force/Area, p=f/APressure = Force/Area, p=f/A units are pascals (Pa)units are pascals (Pa)

Fluids exert pressure evenly in all Fluids exert pressure evenly in all directionsdirections

Pascal’s principle: a change of pressure at Pascal’s principle: a change of pressure at any point in an enclosed fluid will be any point in an enclosed fluid will be transmitted equally to all parts of the fluid:transmitted equally to all parts of the fluid:

pp11=p=p22

Hydraulic devices make use of Pascal’s principle in Hydraulic devices make use of Pascal’s principle in using liquids (eg, oils) to multiply forcesusing liquids (eg, oils) to multiply forces

Fluids in MotionFluids in Motion Fluids move faster through smaller areas Fluids move faster through smaller areas

than large ones if the overall flow rate than large ones if the overall flow rate remains the sameremains the same

• Like a garden hose or blood through vesselsLike a garden hose or blood through vessels Viscosity is a liquid’s resistance to flow:Viscosity is a liquid’s resistance to flow:

Honey has a higher viscosity than waterHoney has a higher viscosity than water Bernoulli’s Principle: as the speed of a Bernoulli’s Principle: as the speed of a

moving fluid increases, the pressure of the moving fluid increases, the pressure of the moving fluid decreasesmoving fluid decreases

Section 3Section 3

Behavior of GasesBehavior of Gases

Properties of gasesProperties of gases No definite shape or volume, fill their containersNo definite shape or volume, fill their containers Particles move rapidly in all directionsParticles move rapidly in all directions Gases are fluidsGases are fluids Molecules are in constant motion, colliding with Molecules are in constant motion, colliding with

each other and walls of container (exerting each other and walls of container (exerting pressure on container)pressure on container)

Have very low density, mostly empty spaceHave very low density, mostly empty space Are compressibleAre compressible Spread out easily and mix with one anotherSpread out easily and mix with one another

Gas Laws: Boyle’s LawGas Laws: Boyle’s Law The volume of a gas The volume of a gas

decreases as the decreases as the pressure on the gas pressure on the gas increases (at constant increases (at constant temperatures).temperatures).

(Pressure(Pressure11)(volume)(volume11) = ) = (Pressure(Pressure22)(volume)(volume22))

PP11VV11=P=P22VV22

Gas Laws: MoreGas Laws: More Charles’s Law: The volume of a gas Charles’s Law: The volume of a gas

increases as the temperature of the gas increases as the temperature of the gas increases (at constant pressure)increases (at constant pressure)VolumeVolume11 = = VolumeVolume22

TemperatureTemperature11 Temperature Temperature22

Gay-Lussac’s Law: The pressure of a Gay-Lussac’s Law: The pressure of a gas increases as the temperature of the gas increases as the temperature of the gas increases (for a given volume).gas increases (for a given volume).