Presentation on theme: "Kinetic Theory of Matter"— Presentation transcript:
1Kinetic Theory of Matter Originally created by Emily AdamsonEdited by M.Elizabeth
2What’s the Kinetic Theory of Matter? It’s a theory that helps explain difference between the states of matter.
3The Kinetic Theory of Matter states… Matter is made up of constantly moving molecules or atoms.
4Under the Kinetic Theory of Matter… Solids’ particles are so close to each other that they only vibrate in place.
5Under the Kinetic Theory of Matter… Liquids’ particles have more space to move than solids, but there is still an attraction between them.
6Under the Kinetic Theory of Matter… Gases’ particles are far apart and move around because the attraction is so low it can be disregarded.
7Substances can change into different phases of matter and back. WHY DOES THIS HAPPEN?
8First, we need to know about…. Kinetic Energy is energy of motion. There are multiple forms, such as:VibrationalRotationalTranslational.
9First, we need to know about…. Thermal energy is total kinetic energy of all of a substance’s atoms and molecules .Kinetic Energy
10First, we need to know about…. Temperature is the average amount of kineticenergy in an object.
11Matter can change into different phases because the exchange of thermal energy between a substance and the environment. Forces that hold substances in one phase are overcome with the addition of energy
12Everything wants to be in its lowest state of energy Everything wants to be in its lowest state of energy. That’s why the exchange occurs!
13Increases as temperature increases Thermal EnergyIncreases as temperature increasesIncreases as kinetic energy increasesTemperatureIncreases as thermal energy increasesKinetic EnergyMotion increases as temperature increases
14THEY’RE ALL INTERTWINED! Overall, when temperature increases, atoms andmolecules’ motion increases (kinetic energy).Thermal energy increases because the total amount ofkinetic energy increased due to the temperaturechange.THEY’RE ALL INTERTWINED!
17SOLIDS Fixed shape and volume Normally hard and rigid Large force needed to change shapeHigh densityIncompressible
18Model of Solids Closely packed together Occupy minimum space Regular patternVibrate about fixed positionNot free to move about
19LIQUIDSFixed volume but no fixed shapeHigh densityNot compressible
20Model of LiquidsOccur in clusters with molecules slightly further apart as compared to solidsFree to move about within confined vessel
21GASESNo fixed shape or volumeLow densityCompressible
22Model of Gases Very far apart Travel at high speeds Independent and random motionNegligible forces of attraction between them
23Brownian Motion Movement of smoke under the microscope Random motion High concentration to low concentration until uniform (all the same = homogeneous)Increases with increasing temperature (thermal energy)
24Pressure in Gases (Ideal Gases) Air molecules in a container are in as state of continuous motion.
25Pressure in Gases (Ideal Gases) Air molecules in a container are in as state of continuous motion.When they collide with the wall of a container, they exert a force, F on the wall.F
26Pressure in Gases (Ideal Gases) Air molecules in a container are in as state of continuous motion.FWhen they collide with the wall of a container, they exert a force, F on the wall.The force per unit area is the pressure exerted on the wall.
27Pressure-volume (p-V) relationship of a gas Air molecules in a container will exert a certain amount of pressure.
28Pressure-volume (P-V) relationship of a gas Air molecules in a container will exert a certain amount of pressure.If the volume of this container was to decrease, the air molecules will have less space to move about. This will result in the molecules colliding with the walls more frequently.
29Pressure-volume (p-V) relationship of a gas Therefore, when we decrease the volume of the container, the pressure exerted by the air molecules on the container increases.
30p1V1 = p2V2 p = k/V pV = k (k is a constant) To form an equation,p = k/VpV = k (k is a constant)p1V1 = p2V2Where p1 and V1 are the initial pressure and volume,And p2 and V2 are the final pressure and volume.
31(600)(1500) = p2(1000) p2= p2= 900 Pa Example: The volume of a fixed mass of gas at 600 Pa is 1500cm3. What is the pressure if the volume is reduced to cm3 at constant temperature?Solution:Using the formula: p1V1 = p2V2(600)(1500) = p2(1000)p2=p2= 900 Pa
32P-T RelationshipNow we will keep the volume of the container constant.We will investigate to see how the pressure will vary with temperature of the gas.
33Pressure increases as the temperature increases. P-T RelationshipFrom the applet, we can see thatPressure increases as the temperature increases.when the volume is kept constant
34ExampleAir is being trapped in a container of fixed volume. At room temperature of 300 K, the pressure exerted by the gas is 100 Pa.If the air in the container was heated to 600 K, what is the new pressure exerted by the gas now?Solution:Since pressure is proportional to temperature, when temperature increases, pressure should also increase.Temperature increases by 2 times, so pressure should increase by 2 times.New pressure = 100 x 2 = 200 Pa
35V-T Relationship at constant pressure This is the most commonly occurring relationship.When gas gets heated, the amount of space that it occupies expands.So when temperature increase, volume would also increase. Temperature is proportional to volume.at constant pressure
36ExampleA balloon is filled with gas, at a temperature of 300 K, to a volume of 50cm3. If I want to expand the balloon to a volume of 150cm3, what is the temperature of the gas now? Assuming that the pressure exerted by the gas does not change.Solution:Volume is proportional to temperature.Since the volume has to be increased by 3 times, the volume should also be increased accordingly.Required temperature = 300 x 3 = 900 K