Chp 11 Gas Laws
Pages 369 377
Boyle’s Law
P
Volume
(mL)
Pressure
(torr)
P·V
(mL·torr)
10.0
20.0
30.0
40.0
760.0
379.6
253.2
191.0
7.60 x 103
7.59 x 103
7.60 x 103
7.64 x 103
PV = k
V
Boyle’s Law
The pressure and volume of a
gas are inversely related
(at constant mass & temp)
P
PV = k
V
Boyle’s Law
Boyle’s Law
4e20.40.mpeg
No sound … In all movies, the air is being
pumped out from the jar, which DECREASES
PRESSURE. You can easily see that the
VOLUME of a gas INCREASES as you
DECREASE PRESSURE!
Boyle’s Law
P 1 V 1 = P2 V 2
Initial Pressure
and Volume
Changed Pressure
and Volume
V2
Boyle’s Law
Practice Problem #1
P1
V1
A gas occupies a volume of 458 mL at
a pressure of 1.01 kPa and
temperature of 295 K. When the
pressure is changed, the volume
becomes 477 mL, If there has been no
change in temperature, what is the new
pressure?
P 1 V1 = P2 V2
Boyle’s Law
P 1 V1 = P 2 V2
(1.01 kPa)(458 mL) = P2 (477 mL)
P2 =
P2 =
(1.01 kPa) (458 mL)
(477 mL)
0.970 kPa
Charle’s Law
V
T
Volume
(mL)
Temperature
(K)
V/T
(mL/K)
40.0
44.0
47.7
51.3
273.2
298.2
323.2
348.2
0.146
0.148
0.148
0.147
V
k
T
Charle’s Law
The volume of a fixed amount
of gas is directly proportional
to its absolute temperature.
(at constant pressure)
V
T
V
k
T
Charle’s Law
No sound … it is easy to see that as
the gas TEMPERATURE INCREASES,
the VOLUME INCREASES!
Charle’s Law
V1
T1
Initial Volume
and Temperature
=
V2
T2
Changed Volume
and Temperature
T2
Charle’s Law
V1
T1
Practice Problem #6
What will be the volume of a gas
sample at 309 K if its volume at 215 K
is 3.42 L
V1
T1
=
V2
T2
Charle’s Law
V1
T1
=
3.42 L
215 K
V2
T2
=
V2
309 K
(3.42 L) (309 K)
V2 =
215 K
= 4.92 L
Dalton’s Law
The sum of the partial
pressures of all the
components in a gas
mixture is equal to the
total pressure of the gas
mixture.
Ptotal = P1 + P2 + P3 ...
Dalton’s Law
P1
P2
Practice Problem #13
What is the pressure of a mixture of
helium, nitrogen, and oxygen if their
partial pressures are 600. mm Hg, 150.
mm Hg, and 102 mm Hg?
P3
Ptotal = P1 + P2 + P3
Dalton’s Law
Practice Problem #13
What is the pressure of a mixture of
helium, nitrogen, and oxygen if their
partial pressures are 600. mm Hg, 150.
mm Hg, and 102 mm Hg?
Ptotal = P1 + P2 + P3
Ptotal = 600 + 150 + 102
Ptotal = 852 mm Hg
*Dalton’s Law
Practice Problem #16
The barometer shows the atmospheric
pressure to be 762 mm Hg. What is the
partial pressure of nitrogen if nitrogen
makes up 78% of the air.
762 mm Hg (0.78) = 594 mm Hg
Gay-Lussac’s Law
The pressure of a
fixed mass of gas
at constant volume
varies directly with
the Kelvin
temperature.
P1
P2
=
T1
T2
Combined Gas Law
P
V
PV
PV = k
T
P 1V 1 P 2V 2
=
T1
T2
P 1 V 1T 2 = P 2V 2 T 1
Avogadro’s Law
Equal volumes of gases
at the same temperature
and pressure contain an
equal number of
particles.
V = k3n
volume
Constant (molar volume of a gas at STP)
Number of moles
Avogadro’s Law
If you keep
pressure and
temperature
constant, what
is the only way
to increase the
volume?
BY INCREASING
THE NUMBER
OF PARTICLES!
V = k3n