Kinetic Molecular Theory Flashcards
Postulate 1
All matter is made up of tiny particles (atoms, molecules)
Postulate 2
Particles are in a constant, random motion (straight lines)
Collide with each other & walls of container. When collide with walls container exerts a pressure.
Postulate 3
The particles DO NOT repel or attract each other, so they are elastic.
Postulate 4
The particles are soooooo small compared to the distances between them, that their volume is considered to be zero. (Point Mass)
Postulate 5
The Kinetic Energy (KE) of the particles is directly proportional to the Kelvin Temperature.
What is the formula for pressure?
Force/Area
Force/area
PRESSURE
Force/AREA
pressure
What is pressure caused by? (2)
- Force of the collisions with the container walls.
- Number of collisions with container walls.
List the factors that affect pressure (3)
- Add more particles
- Decrease Vloume
- Increase heat = Increase KE = Increase Collisions
Atmospheric Pressure
Pressure exerted on the earth by the gas molecules in the atmosphere. Higher at lower altitudes
What are the standard units of pressure?
1 ATM = 750 mmHg = 760 Torr = 101.3 kPa = 14.7 lbs/in²
What is the formula for KE?
½mv²
Temperature
The average KE of the sample
(Same Temp. —-> Same KE)
True or False: If Gas A and Gas B are held at the same temperature, the kinetic energy of both gasses is the same?
True
If Gas A and Gas B have the same average kinetic energy, but Gas B is 3x heavier than Gas A which Gas will have the higher/faster velocity?
Gas A
Energy always moves from ______ to _____
High; Low
How is temperature related to the KE of a gas?
Measures average KE of the particles
In order to transfer heat energy from a warm object to a colder object what must happen to the particles?
The particles must collide/touch with each other
°C —-> K
Tk = Tc° + 273
°F —> °C
Tf = 1.8 * °C + 32
What does absolute zero mean in terms of molecular motion?
There is no molecular motion or pressure of any kind
Solid: Motion, Shape, Volume
Motion) Vibrate around a fixed point
Shape) Definite
Volume) Definite
Liquid: Motion, Shape, Volume
Motion) Vibrate around a fixed point
Shape) Indefinite - takes shape of container
Volume) Definite
Gas: Motion, Shape, Volume
Motion) Random straight lines
Shape) Indefinite - takes shape of container
Volume) Indefinite - takes shape of container
Point A
Solid
Point B
Liquid
Point C
Gas
Solid —> Liquid/Liquid —> Solid
Melting/Freezing
Temp where pressure of solid = pressure of liquid
Liquid —> Gas/Gas —> Liquid
Vaporization/Condensation
Temp where pressure of liquid = pressure of gas
Solid —> Gas/Gas —> Solid
Sublimation/Deposition
Triple Point
Temp & pressure where Solid, Liquid, Gas exist at the same time
Critical Point
Temp & pressure above which no amount of pressure can liquefy the gas
Graham’s Law Formula
Va/Vb = square root(Mb/MA
Gas A = Lighter Gas
Gas B = Heavier Gas
