6 Gases Flashcards
At STP: Pressure =
Temperture=
Pressure = 1 atm = 760 mmHg
Temperature = 0º C =273 K
At STP, 1 mole of gas occupies
22.4 liters
The total Kinetic Energy of a Gas Sample
KE =
(3/2)nRT
R = the gas constant; 8.31 Joules/mol•K
T = absolute temperature (K)
n = number of moles (Mol)
The Average Kinetic Energy of a Single Gas Molecule
KE =
(1/2)mv2
m = mass of the molecule (kg)
v = speed of the molecule (meters/sec)
KE is measured in Joules
The Ideal Gas Equation
PV =
nRT
P= pressure of the gas (atm)
V = Volume of the gas (L)
n = number of moles of gas
T= the absolut temperature of the gas (K)
R = the gas constant, 0.0821 L•atm/ mol•K
(P1V1)/T1 =
(P2V2)/T2
If the volume is constant: As pressure increases,
temperature increases; as temperature increases, pressure increases
If the temperature is constant: As pressure increases, volume
decreases; as volume increases, pressure decreases. That’s Boyle’s law.
If the pressure is canstant: As temperature increases, volume
increases; as volume increases, temperature increases. That’s Charles’s law
Dalton’s Law
Ptotal =
Pa + Pb + Pc +. . .
Partial Pressure
Pa =
(Ptotal)(Xa)
Xa = moles of gas A / total moles of gas
urms =
Square Root(3kT/m) = Square root(3RT/M)
urms = average speed of a gas molecule (Meters/Sec)
T = absolute temperature (K)
m = (mass of the gas molecule (kg)
M = molecular weight of the gas (kg/mol)
k = Boltzmann’s constant, 1.38 X 10-23 Joule/K
R = the gas constant, 8.31 joules/mol•K
r1/r2
Square Root(M2/M1)
r = rate of effusion of a gas or average speed of the molecules of a gas
M = molecular weight
D =
M/V
D = density
m = mass of gas, usually in grams
V = volume occupied by a gas, usually in liters
At a given temperature, lighter molecules move
faster than heavier molecules.
