Ideal Gas Law
Gases
 Fluid that explains to fill the space that contains it.
 Free molecules undergoing breif, elastic collisons.
 Highly compressible,
 Flows from higher to lower pressure,
 Generally act “ideally”.
Pressure
Pressure is described as Force Exerted / Area of affected region. Also commonly know as Newtons / m^2
$ Pressure = \frac{(kg)(s^2)}{m} $
This unit is called the Pascal (Pa)
 Units
 IUPAC: Standard Pressure = 100,000 Pa = 1 bar
 mmHg: millimeters of mercury in a barometer = 1 Torr
 $ 1 Atm = 760 Torr = 101325 Pa = 101.325 kPa = 1.01325 $
The Gas Laws
 The properties of gases were elucidated over many tears by several scientists.
 PressureVolume: Robert Boyle and Robert Hooke
 VolumeTemperature: J.A.C. Charles
 VolumeAmount: Amedeo Avogadro
 PressureTemperature: Guiaume Amontons
 $ PV = nRT $ <– Ideal Gas Law
Ideal Gas Law
 Law applies STRICKLY to ideal, noninteracting gases.
 Law applies APPROXIMATELY under condictions where gas molecules interact only weakly.

Most common gases act like “ideal gases” under typical conditions.
 PV = nRT
 n is Number of moles.
 T is temperature in moles.
 P is pressure
 V is Volume
 Boyles Law:
 If n and T are constant:
 $ PV = (nRT) = C $
 $ P_1V_1 = P_2V_2 $
 If n and T are constant:
 Charles’s Law:
 Keeping P and n constant:
 $ V (nR/P)T = CT $
 $ (V_1/T_1) = (V_2/T_2) $
 Keeping P and n constant:
 Avogadro’s Law:
 Keep P and T constant:
 $(V_1/n_1) = (V_2/N_2)$
 $V = (RT/P)n = Cn$
 Keep P and T constant:
Using the Ideal Gas Law
Solve for Volume:
 $ V = nRT/P $
Solve for pressure:
 $ P = nRT / V $
Solve for amount:
 $ n = PV/RT $
Gas Constants
Value  Units  Pressure  Volume 

8.31446  m^3 Pa K mol  Pa  m^3 
8.31446x10^5  m^3 bar K mol  bar  m^3 
8.31446x10^2  L bar K mol  bar  L 
62.36358  L Torr K mol  Torr  L 
8.205734x10^2  L atm K mol  Atm  L 