Kinetic Theory of Matter

Kinetic Theory of MatterOriginally created by Emily AdamsonEdited by M.ElizabethWhats the Kinetic Theory of Matter?Its a theory that helps explain difference between the states of matter.

The Kinetic Theory of Matter statesMatter is made up of constantly moving molecules or atoms.

Under the Kinetic Theory of MatterSolids particles are so close to each other that they only vibrate in place.

Under the Kinetic Theory of MatterLiquids particles have more space to move than solids, but there is still an attraction between them.

Under the Kinetic Theory of MatterGases particles are far apart and move around because the attraction is so low it can be disregarded.

Substances can change into different phases of matter and back.

WHY DOES THIS HAPPEN?

First, we need to know about.

Kinetic Energy is energy of motion. There are multiple forms, such as:VibrationalRotationalTranslational.

First, we need to know about.

Thermal energy is total kinetic energy of all of a substances atoms and molecules .

Kinetic EnergyFirst, we need to know about.

Temperature is the average amount of kineticenergy in an object.

Matter can change into different phases becausethe exchange of thermal energy between a substance and the environment. Forces that hold substances in one phase are overcome with the addition of energy

Everything wants to be in its lowest state of energy. Thats why the exchange occurs!

Overall, when temperature increases, atoms andmolecules motion increases (kinetic energy).Thermal energy increases because the total amount ofkinetic energy increased due to the temperaturechange.

THEYRE ALL INTERTWINED!

KINETIC THEORY OF MATTER

3 STATES OF MATTERSOLIDLIQUIDGAS

Model of SolidsClosely packed togetherOccupy minimum spaceRegular patternVibrate about fixed positionNot free to move about

Model of LiquidsOccur in clusters with molecules slightly further apart as compared to solidsFree to move about within confined vessel

Model of GasesVery far apartTravel at high speedsIndependent and random motionNegligible forces of attraction between themBrownian MotionMovement of smoke under the microscopeRandom motionHigh concentration to low concentration until uniform (all the same = homogeneous)Increases with increasing temperature (thermal energy)

Pressure in Gases (Ideal Gases)Air molecules in a container are in as state of continuous motion.Pressure 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.FPressure 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.FThe force per unit area is the pressure exerted on the wall.Pressure-volume (p-V)relationship of a gasAir molecules in a container will exert a certain amount of pressure.Pressure-volume (P-V)relationship of a gasAir 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. Pressure-volume (p-V)relationship of a gasTherefore, when we decrease the volume of the container, the pressure exerted by the air molecules on the container increases.

To form an equation,p = k/VpV = k (k is a constant)p1V1 = p2V2

Where p1 and V1 are the initial pressure and volume,And p2 and V2 are the final pressure and volume.Example:The volume of a fixed mass of gas at 600 Pa is 1500cm3. What is the pressure if the volume is reduced to 1000 cm3 at constant temperature?Solution:Using the formula: p1V1 = p2V2(600)(1500) = p2(1000)p2=p2= 900 Pa

P-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.

P-T RelationshipFrom the applet, we can see that Pressure increases as the temperature increases.

when the volume is kept constantExampleAir 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 PaV-T RelationshipThis 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 pressureExampleA 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