Chemistry Ideal Gas Laws Test

Ideal Gases

Imaginary Gases that perfectly fit all of the assumptions of the kinetic molecular theory

List the five assumptions of the kinetic molecular theory

1) consist of tiny particles that are far apart relative to their size.
2) Collisions between gas particles are elastic (no kinetic energy is lost in kinetic collisions)
3) gas particles are in constant, rapid motion, therefore they possess kinetic energy

The nature of gases (5 characteristics)

1) gases expand to fill their containers
2) they are fluid, they flow
3) have low density (1/1000 density of the equivalent solid or liquid)
4) gases are compressible
5) they effuse and diffuse

Elastic Collision

No kinetic energy is lost in particle collisions

Real Gas

Does not behave according to ideal gas law assumptions.

Conditions that make gases act like real gases

More polar gases
high pressures
low temperatures

Pressure

How much force applied to a given area,
caused by the collisions of molecules against the walls of a container

SI unit of pressure

newton/meter^2 = 1 pascal

1 atmosphere

101,325 Pascals (Pa)
AKA 101.325 kilopascals

Conversion factor from atm to torr

1 atm = 760 torr = 760 mmHg = 101.325 KPa

First device used for measuring atmospheric pressure

Barometer
baro means weight
meter means measure

Created the barometer, and in what century

Evangelista Torricelli, 17th century

STP

Pressure = 1 atmosphere, 760 torr, 101.325 Kpa
Temperature = 273.15 Kelvins
Molar volume of an ideal gas is 22.42 liters at STP

Boyle's Law

Pressure is inversely proportional to volume
when temperature is held constant.
P1V1=P2V2

Charles's Law

The volume of a gas is directly proportional to temperature, and extrapolates to zero at zero Kelvin.
(P = constant)
V1/T1 = V2/T2

Gay Lussac's Law

The pressure and temperature of a gas are
directly related, provided that the volume
remains constant.
P1/T1=P2/T2

Combined Gas Law

PV/T = PV/T

Avogadro's Law

For a gas at constant temperature and pressure, the volume is directly proportional to the number of moles of gas (at low pressures).
V = an
AKA V1/n1 = V2/n2
a = proportionality constant
V = volume of the gas
n = number of moles of gas

Ideal Gas Law

PV = nRT
P = pressure in atm
V = volume in liters
n = moles
R = proportionality constant
= 0.08206 L atm/ mol�K
T = temperature in Kelvins
(truest when pressure < 1 atm)

Standard Molar Volume states that

Equal volumes of all gases at the same temperature and pressure contain the same number of molecules.

Equation for molar mass of a gas

M = dRT/P
(d = density)

Gas Density Units

molar mass / volume

Density at STP

22.4 g/ Liter

Formula for density

D = MP/RT
M = Molar Mass
P = Pressure
R = Gas Constant
T = Temperature in Kelvins

Who created the law of partial pressures

Dalton

Law of Partial Pressures

For a mixture of gases in a container,
PTotal = P1 + P2 + P3 + . . .
(When V and T are constant)

How to use law of partial pressures

Two gases in a container. Use ideal gas laws to find pressure of each individually. add those together to get total pressure.

Kinetic Molecular theory

Particles of matter are ALWAYS in motion
Volume of individual particles is zero.
Collisions of particles with container walls cause pressure exerted by gas. (Perfectly elastic collisions)
Particles exert no forces on each other.
Average kinetic energy �

Formula for kinetic energy of gas

KE 1/2 mv^2

formula for average kinetic temperature

KE = 3/2 RT

Diffusion

the mixing of gases.
gradual mixing of molecules of one gas with molecules of another by virtue of their kinetic properties.

Rate of diffusion

rate of different gases mixing

Effusion

Passage of gas into an evacuated chamber
the process by which gas under pressure escapes from one compartment of a container to another by passing through a small opening.

Grahams law for rates of effusion and diffusion

rate = (M)^(-1/2)

Absolute Zero

0 Kelvin, no movement of particles

Proportionality constants for Ideal gas law Kilopascals

8.312 L kPa/ mol K

Proportionality constants for Ideal gas law
atm

0.08206 L atm/ mol kPa

Proportionality constants for Ideal gas law
Joules (use this in KE formulas)

8.3145 J/mol K

Mole Fraction

ratio of the number of moles of a given component in a mixture to the total number of moles in the mixture