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G-L’s LAW – Pressure vs. Temperature
Pre
ssur
e (k
Pa)
Volume (mL)
BOYLE’S LAW – Pressure vs. Volume
=
P1V1 P2V2
Temperature (K)
Vol
ume
(mL
)
CHARLES’S LAW – Temp vs. Volume
=
V1 V2
T2
T1
•Describe the relationship between the temperature of a gas and its pressure.
•Solve problems involving temperature-pressure relationships.
•Describe some practical applications of Gay-Lussac’s Law.
Joseph Gay-Lussac (1778-1850)
Determined that temperature and pressure of a gas is a direct relationship (volume and amount of gas are held constant)
=
P1 P2
T2
T1
**As with Charles’ Law, temperature in Kelvin.
If a 12.0 L sample of gas is found to have a pressure of 101.3 kPa at 0.0°C, calculate the new pressure at 128°C if the volume is held constant.
0.0°C + 273 = 273 K128°C +273 = 401 K
=
P1 P2
T2
T1
=
101.3 P2 (401) 273
149 kPa
Boyle’s Law: Pressure α ___1___
volume
Charles’ Law: Volume α temperature
Gay-Lussac’s Law: Pressure α temperature
=
P1 P2
T2
T1
V1 V2
combined gas law
If a gas occupies a volume of 25.0 L at 25.0°C and 1.25 atm, calculate the volume at 128°C and 0.750 atm.
=
P1 P2
T2
T1
V1 V2
=
(1.25)(401) 298 (0.750)
25 V2
25°C + 273 = 298 K128°C +273 = 401 K
56.1 L
A gas has a volume of 125 L at 325 kPa and 58.0°C, calculate the temperature in Celsius to produce a volume of 22.4 L at 101.3 kPa
=
P1 P2
T2
T1
V1 V2
=
(101.3) (331) 325 (125)
22.4T2
58°C + 273 = 331 K
18.5 K
18.5 K - 273 = -254°C
A bag contains 145 L of air at the bottom of a lake, at a temperature of 5.20°C and a pressure of 6.00 atm. When the bag is released, it ascends to the surface where the pressure is 1.00 atm and 16.0°C.
Given:P1 = 6.00 atm
V1 = 145L
T1 = 5.20°C
P2 = 1.00 atm
T2 = 16.0°C
Find: V2
If the maximum volume of the lift bag is 750 L, will the bag burst at the surface?
Avogadro’s Hypothesis - any sample of any gas at the same temperature and pressure will contain the same number of particles.
Dalton’s Law of Partial Pressure:
Each gas in a mixture exerts pressure independently.
Total pressure = sum of the pressures of each gas (partial
pressures)
Partial pressure depends on the number of gas particles present (moles), the temperature and volume of container.
Ptotal = P1 + P2 + P3 + P4 …
1.0 mol H2 2.0 mol He 1.0 mol H2
2.0 mol He3.0 mol gas
