Gas
Law Formulas 

Ptotal
= P1 + P2 + P3
... 
Dalton’s
Law of Partial Pressure 
X1 = n1/ntotal = P1/Ptotal 
Mole
Fraction 
P1V1
= P2V2 
Boyle’s
Law 
V1 /
T1
= V2 / T2 
Charles’
Law 
V1 /
n1
= V2 / n2 
Avogadro's
Law 
P1 /
T1
= P2 / T2 
GayLussac’s
Law 
P1V1 / T1 = P2V2 / T2 
Combined
Gas Law 
Graham's
Law 

PV
= nRT R = 8.3145 L kPa/mol K or R= 0.08206 L atm/mol K 
Ideal
Gas Law 
(mm) P
= dRT mm = molar mass d = density R= 0.08206 L atm/mol K 
Gas
Density/Molar Mass 
vrms
=
√(3RT
/ M) M = molar mass in kg / mol R = 8.3145 J/mol K 
Root
Mean Square Velocity 
[Pobs + a(n/V)2] x (V – nb) = nRT 
van
der Waals Equation 
Standard
Atmospheric Pressure: 1 atm = 760 torr = 760 mm Hg = 101.3 kPa = 14.7 psi 