Kinetic TheoryKinetic Theory

Ch 16 Sect 1Ch 16 Sect 1

Kinetic TheoryKinetic Theory

Explanation of how particles in matter Explanation of how particles in matter behavebehave

There are 3 assumptions associated with There are 3 assumptions associated with the kinetic theorythe kinetic theory

1.1. All matter is composed of smaller particles All matter is composed of smaller particles (atoms)(atoms)

2.2. These particles are in constant random motionThese particles are in constant random motion

3.3. These particles collide with each other and their These particles collide with each other and their boundariesboundaries

Kinetic Theory and EnergyKinetic Theory and Energy

The movement of the particles The movement of the particles (atoms) with in an object depend on (atoms) with in an object depend on energyenergy– Energy is measured as heatEnergy is measured as heat– As energy increases (gets hotter) As energy increases (gets hotter)

particle motion increasesparticle motion increases– As energy decreases (gets colder) As energy decreases (gets colder)

particle motion decreasesparticle motion decreases

Measuring Particle EnergyMeasuring Particle Energy

There are 2 different measurements There are 2 different measurements used when measuring the energy within used when measuring the energy within an objectan object

1.1. Thermal energy-When using thermal energy Thermal energy-When using thermal energy you measure the total amount of energy for you measure the total amount of energy for all of the particles in the object (substance)all of the particles in the object (substance)

– More thermal energy = More (faster) motionMore thermal energy = More (faster) motion– Less thermal energy = less (slower) motionLess thermal energy = less (slower) motion

Measuring Particle Energy (cont)Measuring Particle Energy (cont)

2.2. Average Kinetic Energy (AKE)-The average Average Kinetic Energy (AKE)-The average kinetic energy shows the average energy for kinetic energy shows the average energy for all the particles in an object (substance)all the particles in an object (substance)

Most commonly know as the temperature of Most commonly know as the temperature of an object (substance)an object (substance)

As temperature goes up the particles in the As temperature goes up the particles in the object are moving fasterobject are moving faster

As temperature goes down the particles in the As temperature goes down the particles in the object are moving slowerobject are moving slower

Finding Thermal energy and AKEFinding Thermal energy and AKE

Balloon in Flask

The reason this experiment works is because of the kinetic theory of the particles in the flask• As you heat up the flask the molecules begin to

move faster (causes them to escape)

• You cap the flask with the balloon which traps all of the particles (keeps other particles out)

• Put in ice water and the energy decreases which causes the molecules to move slowly and come back together (sucks the balloon in)

States of MatterStates of Matter

Matter-Anything that has mass and Matter-Anything that has mass and occupies spaceoccupies space

There are 3 common types of There are 3 common types of matter on earthmatter on earth

• Solid, liquid, gasSolid, liquid, gas 44thth type of matter is most common type of matter is most common

and found in stars of our universeand found in stars of our universe• PlasmaPlasma

Solid Matter

In a solid the particles inside the object are packed closer together These particles have less energy then

liquid and gas states Most solids have a specific geometric

arrangement for their particles Ex-Picture of water on pg 489 of your text

book Solids have a fixed shape and volume

Liquid MatterLiquid Matter

As temperature increases the particles As temperature increases the particles start moving fasterstart moving faster

Eventually they gain enough KE to Eventually they gain enough KE to temporarily move past their boundariestemporarily move past their boundaries– Slide past each otherSlide past each other– More energy then solids but less then More energy then solids but less then

gases gases Liquid has a fixed volume but not a Liquid has a fixed volume but not a

fixed shapefixed shape Solids melt to a liquid at heat of fusionSolids melt to a liquid at heat of fusion

Gas Matter

Gases have enough kinetic energy to overcome all the attractions between the particles

Gases have more energy then liquids and solids

Gases do not have fixed volume or shape

Liquids turn to gases when they hit the heat of vaporization

Heating Curve (S to L to G)

1. As you start to heat up a solid the temperature begins to rise

2. The temperature will rise till it reaches the heat of fusion– At this point all energy goes into

breaking away from chemical bonds

Heating Curve (S to L to G)

3. Once substance becomes a liquid the temperature begins rising again

4. Temperature continues to rise until it reaches the heat of vaporization

– Once again energy goes into particles breaking its chemical bonds

Gas to LiquidGas to Liquid

• There are two different ways a gas There are two different ways a gas can go to a liquidcan go to a liquid

1.1. Evaporation-One molecule overcomes Evaporation-One molecule overcomes the attractive forces at a time. the attractive forces at a time. – Evaporation is slow enough that you cant Evaporation is slow enough that you cant

see it happen see it happen

2.2. Boiling-Lots of molecules overcome Boiling-Lots of molecules overcome the attractive forces at a timethe attractive forces at a time– Happens with high heat or low pressureHappens with high heat or low pressure

Pressure and States of Pressure and States of mattermatter

►Pressure is the other variable that can Pressure is the other variable that can affect states of matteraffect states of matter High pressure causes the molecules to stick High pressure causes the molecules to stick

to be pressed togetherto be pressed together►Can cause a gas to go to a liquid or a liquid to a Can cause a gas to go to a liquid or a liquid to a

solidsolid Example = Dry iceExample = Dry ice

Low pressure allows the molecules to Low pressure allows the molecules to spread outspread out

►Can cause a solid to go to a liquid or a liquid to a Can cause a solid to go to a liquid or a liquid to a gasgas

Example boiling cold waterExample boiling cold water

Thermal ExpansionThermal Expansion

Expansion of materials do to rising Expansion of materials do to rising temperaturestemperatures Higher temperature = increase in size of Higher temperature = increase in size of

objectobject Particles move faster/increase distance betweenParticles move faster/increase distance between

Lower temperature = decrease in size of Lower temperature = decrease in size of objectobject Particles move slower/decrease distance betweenParticles move slower/decrease distance between

Diffusion

Movement of molecules from a high concentration to a low concentration Happens because of the law of entropy

Law of entropy states that everything will go from a state of order to a state of disorder unless energy is added to keep it organized

Will particles diffuse quicker in hot water or cold water?

Making Ice CreamMaking Ice Cream

To make ice cream we take a liquid (milk) and To make ice cream we take a liquid (milk) and other ingredients (for flavor) mix them other ingredients (for flavor) mix them together and then take away thermal energytogether and then take away thermal energy Taking away the thermal energy causes the Taking away the thermal energy causes the

molecules to slow down, which in turn causes the molecules to slow down, which in turn causes the state of matter to change from a liquid to a solid state of matter to change from a liquid to a solid

Materials Needed for making Ice CreamMaterials Needed for making Ice Cream

1 gallon ziploc bag1 gallon ziploc bag 1 quart ziplock bag1 quart ziplock bag 6 cups of ice6 cups of ice 1/31/3rdrd cup of salt cup of salt 1 cup of whole milk1 cup of whole milk 1 teaspoon of vanilla or strawberry 1 teaspoon of vanilla or strawberry

extractextract 2 table spoons of sugar2 table spoons of sugar

ProcedureProcedure

Pour milk, extract, and sugar into a Pour milk, extract, and sugar into a small bag (get any extra air out and small bag (get any extra air out and seal it)seal it)

Place small bag in large bag and Place small bag in large bag and cover with ice and salt (seal bag)cover with ice and salt (seal bag)

Shake bag until liquid solidifiesShake bag until liquid solidifies Usually 8-12 minutesUsually 8-12 minutes

Ice Cream LabIce Cream Lab

Which type of milk allows ice cream Which type of milk allows ice cream to freeze faster?to freeze faster? Non-Fat or 2% fatNon-Fat or 2% fat