Gas Laws Flashcards
Gases consist of atoms:
He Ne Ar Kr Xe Rn
Or gases consist of diatomic molecules:
H2 N2 O2 F2 Cl2
Or gases consist of polyatomic molecules
CH4
SO3
Etc
Vapors are
Substances in a gaseous state that are normally solid or liquid
Four characteristics of gases
Pressure(P)
Volume(V)
Temperature(T)
Particles(k)
Pressure
Force applied by the gas (atm, kPa, mmHg)
Atmospheric pressure
Force applied by the “weight” of the atmosphere on us
Standard pressure
1atm=101.3 kPa=760 mmHg
Dalton’s law
A mixture of gases has a pressure equal to the sum of the partial pressures
Ptotal = p1+ p2 + …
Volume
Amount of space occupied by the gas
Temperature
Average kinetic energy of gas
Standard temperature
0•c = 273 K
Bottles law
P1v1= p2v2
Charles law
V1/t1 = v2/ t2
Gay Lusaks law
P1/t1 = p2/t2
Combined gas law
P1v1/t1 = p2v2/t2
Avogadros hypothesis
Equal volumes of gases contain the same number of particles (at the same t and p)
Ideal gas law
P1v1/n1t1 = p2v2/n2t2
Or
pv = nRT
Density =
Molar mass/ volume
Why does d=m/v
Scince 1 mile of any gas occupies a volume of 22.4 L at stp and one mile of a gas has a mass equal to its molar mass, the density of gas can be calculated by mm/22.4
If you multiple mm on both sides of the equation density equals
P•mm/RT
Gases in a mixture will
Behave independently of each other
P1 = n1 (RT/V) P2= n2 (RT/V)
A mixture of gases would occupy the same container… Meaning
The same t and v for each gas
Ptotal= (n1+n2+n3)(RT/V)
=
ntotal (RT/V)
Amount of gas in a mixture is related to
It partial pressure
P1/Pt = n1/nt
Mole fraction
n1/nt
The mole fraction, X, is the ratio of
Moles of one gas to the total number of miles in the mixture
P1 = (n1/nt) Pt
=
X1P1
Kinetic molecular theory
- Gases consist of a lot of molecules in continuous, random motion
- The total volume of the molecules is negligible compared to the volume occupied by the gas
- Attractive and repulsive forces between gas molecules is negligible
- Energy can be transferred from a molecule to another, but it is never lost “perfectly elastic”
- The average kinetic energy of a gas molecules is proportional to the kelvin temperature scale
Kelvin temperature scale
Has only + values
The lowest temperature is absolute 0, 0K
All molecular activity stops at
0K
Effusion
Gas escaping through a tiny hole in its container
Diffusion
A gas moving from an area of high concentration to an area of low concentration
Both effusion and diffusion depend on
Molar mass of a gas
Lighter gases move faster
TRU
K.E. = (1/2) mv^2
TRU
Graham’s law of effusion
Effusion rates are inversely proportional to the square root of its molar mass
Gases consist of
Nonmetallic elements
