1. Ideal Gas Law (Equation):
P = Pressure
PV = nRT
V = Volume
n = number of moles
R = ideal gas constant
T = Temperature (K)

2. R = PV = (1 atm )(22.4 L) R = 0.0821 L * atm
We can calculate R by looking at 1 mol of a gas
at STP:
STP = 273 K and 1 atm
@ STP, 1 mol of a gas occupies 22.4 L
R = PV = (1 atm )(22.4 L)
nT (1 mol)(273 K)
R = L * atm
mol * K

3. Use ideal gas law, PV=nRT.
Practice Problem
A 23.8-L cylinder contains oxygen gas at C
and 732 torr. How many moles of oxygen are in the
cylinder?
PV = n RT
Use ideal gas law, PV=nRT.
Pressure must be in atm, Temperature in K:
732 torr x 1 atm = atm
760 torr
(0.963 atm)(23.8 L) = n
( L atm/mole K)(293 K )
= mol

4. Do Problems: 20, 22, & 24 pg 453
26-29 pg 455