Kinetic Theory Ch 16 Sect 1

Kinetic Theory Explanation of how particles in matter behave Explanation of how particles in matter behave There are 3 assumptions associated with the kinetic theory There are 3 assumptions associated with the kinetic theory 1. All matter is composed of smaller particles (atoms) 2. These particles are in constant random motion 3. These particles collide with each other and their boundaries

Kinetic Theory and Energy  The movement of the particles (atoms) with in an object depend on energy –Energy is measured as heat –As energy increases (gets hotter) particle motion increases –As energy decreases (gets colder) particle motion decreases

Measuring Particle Energy  There are 2 different measurements used when measuring the energy within an object 1. Thermal energy-When using thermal energy you measure the total amount of energy for all of the particles in the object (substance) –More thermal energy = More (faster) motion –Less thermal energy = less (slower) motion

Measuring Particle Energy (cont) 2. Average Kinetic Energy (AKE)-The average kinetic energy shows the average energy for all the particles in an object (substance) Most commonly know as the temperature of an object (substance) Most commonly know as the temperature of an object (substance) As temperature goes up the particles in the object are moving faster As temperature goes up the particles in the object are moving faster As temperature goes down the particles in the object are moving slower As temperature goes down the particles in the object are moving slower Finding Thermal energy and AKE Finding Thermal energy and AKE Finding Thermal energy and AKE Finding 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 Matter Matter-Anything that has mass and occupies space Matter-Anything that has mass and occupies space There are 3 common types of matter on earth There are 3 common types of matter on earth Solid, liquid, gasSolid, liquid, gas 4 th type of matter is most common and found in stars of our universe 4 th type of matter is most common and 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 Matter As temperature increases the particles start moving faster As temperature increases the particles start moving faster Eventually they gain enough KE to temporarily move past their boundaries Eventually they gain enough KE to temporarily move past their boundaries –Slide past each other –More energy then solids but less then gases Liquid has a fixed volume but not a fixed shape Liquid has a fixed volume but not a fixed shape Solids melt to a liquid at heat of fusion Solids 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 Liquid There are two different ways a gas can go to a liquidThere are two different ways a gas can go to a liquid 1.Evaporation-One molecule overcomes the attractive forces at a time. –Evaporation is slow enough that you cant see it happen 2.Boiling-Lots of molecules overcome the attractive forces at a time –Happens with high heat or low pressure

Pressure and States of matter ► Pressure is the other variable that can affect states of matter  High pressure causes the molecules to stick to be pressed together ► Can cause a gas to go to a liquid or a liquid to a solid  Example = Dry ice  Low pressure allows the molecules to spread out ► Can cause a solid to go to a liquid or a liquid to a gas  Example boiling cold water

Thermal Expansion  Expansion of materials do to rising temperatures  Higher temperature = increase in size of object  Particles move faster/increase distance between  Lower temperature = decrease in size of object  Particles 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 Cream To make ice cream we take a liquid (milk) and other ingredients (for flavor) mix them together and then take away thermal energy To make ice cream we take a liquid (milk) and other ingredients (for flavor) mix them together and then take away thermal energy Taking away the thermal energy causes the molecules to slow down, which in turn causes the state of matter to change from a liquid to a solid Taking away the thermal energy causes the molecules to slow down, which in turn causes the state of matter to change from a liquid to a solid

Materials Needed for making Ice Cream 1 gallon ziploc bag 1 gallon ziploc bag 1 quart ziplock bag 1 quart ziplock bag 6 cups of ice 6 cups of ice 1/3 rd cup of salt 1/3 rd cup of salt 1 cup of whole milk 1 cup of whole milk 1 teaspoon of vanilla or strawberry extract 1 teaspoon of vanilla or strawberry extract 2 table spoons of sugar 2 table spoons of sugar

Procedure Pour milk, extract, and sugar into a small bag (get any extra air out and seal it) Pour milk, extract, and sugar into a small bag (get any extra air out and seal it) Place small bag in large bag and cover with ice and salt (seal bag) Place small bag in large bag and cover with ice and salt (seal bag) Shake bag until liquid solidifies Shake bag until liquid solidifies Usually 8-12 minutes Usually 8-12 minutes

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