Ideal Gas Law (ref. p443)
Ideal Gas – a hypothetical gas composed of particles that have zero size, travel in straight lines,
and have no attraction to each other (zero intermolecular force).
Situations where gases behave quite ideally
Situation where gases behave not very ideally
Low pressure, particles are far apart.
High pressure, particles are close together.
Avogadro noticed: X(g) + Y(g)  XY (g)
1L
1L
pv

= R
…since n  V, n=kV,
nT
1L
R is known as the Gas Constant. It relates the pressure, volume, mole amount and temperature
(in KELVIN!) of an ideal gas.
Ideal Gas Law: pv = nRT
pg.443: at STP, 1.00mol occupies 22.414 L (memorize)
pg.482: at SATP 24.8L/mol
-1 -1
pg.444: R=8.31 kPa·L·mol K (one set of possible units, always provided, do not memorize)
ex. Sample problem 1 pg. 444
What mass of neon gas should be introduced into an evacuated 0.88 L tube to produce a
pressure of 90 kPa at 30°C?
v = 0.88 L; p = 90 kPa; mNe = ?;
T = 30°C = 303 K
pv = n Ne RT
n Ne 
pv
RT
= 90 kPa  0.88 L
 0.031 mol
1 mol  K IF 1 I
F
G
H8.31 kPa  L J
KG
H303 K J
K
F
G
H
IJ
K
0.031 mol 20.18 g
1 mol
= 0.63 g
 The mass of neon needed is 0.63 g.
m Ne 