1. Pressure – Temperature:
Gay-Lussac and Dalton

2. OUTCOME QUESTION(S): C11-2-07 UNITS AND RELATIONSHIPS
Describe the various units used to measure pressure and convert between units.
Include: atmospheres, kilopascals, millimetres of mercury
Experiment to develop the relationship between the pressure and volume of a gas using visual, numeric, and graphical representations.
Include: Boyle’s Law
Experiment to develop the relationship between the volume and temperature of a gas using visual, numeric, and graphical representations.
Include: Charles’ Law, Absolute zero, Kelvin scale, Ideal gas
Develop the relationship between the pressure and temperature of a gas using visual, numeric, and graphical representations.
Include: Gay-Lussac’s Law, Dalton’s Law
Vocabulary & Concepts 
Partial pressure

3. pressure and temperature show a constant direct relationship
Joseph Louis Gay-Lussac: ( )
Experimented with pressure and temperature of a sample at constant volume.
Data plotted – as pressure vs. temperature
Linear relationship emerges (a straight line)
Slope is constant and predictable
rise = constant
run P
= constant T
pressure and temperature show a constant direct relationship
rise
run

4. (when held at a constant volume)
Gay-Lussac’s Law:
The pressure of a given amount of gas varies directly with the temperature in Kelvin.
(when held at a constant volume)
P α T

5. What is the new pressure of 200 kPa of gas if the temperature in Kelvin is doubled?
P α T
A direct relationship suggests:
400 kPa
2 α 2
Double the temperature will double
the original pressure
If temperature is reduced to 1/3rd ?
1 3 α 1 3
66.7 kPa
Decreased temperature will reduce
pressure to 1/3 the original
Direct of a third is a third

6. = P1 T1 P2 T2 P1 T1 P2 T2 G-L’s Law Equation: P = constant T
rise
run
**All temperatures must be in Kelvin.
P = constant T P1 T1 P2 T2
Initial conditions always equal Final conditions when divided

7. If a 12. 0 L sample of gas has a pressure of 101. 3 kPa at 0
If a 12.0 L sample of gas has a pressure of kPa at 0.0°C, calculate the new pressure at 128°C.
P1 = kPa
T1 = 0oC = 273 K
P2 = ?
T2 = 128oC = 401 K P1 P2 = T1 T2
Predicted result?
101.3
149 kPa = P2
(401)
273
Increasing the temperature by 128 degrees will cause an increase in pressure to 149 kPa

8. (when held at a constant temperature)
Dalton’s Law of Partial Pressure:
The total pressure is the sum of the partial pressures exerted by each gas in a container.
(when held at a constant temperature)
Ptotal = P1 + P2 + P3 + P4 …
The partial pressure of a gas in a mixture is the same as the pressure of the gas in the container by itself

9. Ptotal = P1 + P2 + P3 + P4 … PT = 50.5 + 20.0 + 30.5 PT = 101 kPa
The following gases are found in a 10.0 litre container and held at 250 K, what is the total pressure inside the container?
O2 gas with a partial pressure of kPa
He gas with a partial pressure of 20.0 kPa
Ar gas with a partial pressure of 30.5 kPa
Ptotal = P1 + P2 + P3 + P4 …
PT =
PT = kPa

10. PT = PO2 + PHe + PX PX = 25 - 15 - 7 PX = 3 atm
A mixture of three gases in a 30.0 litre container, held at 270 K have a total pressure of 25 atm. What is the partial pressure of the unknown gas?
O2 - partial pressure = 15 atm
He - partial pressure = 7 atm
X - partial pressure = ?
PT = PO2 + PHe + PX
PX =
PX = 3 atm

11. Two individual gases held in containers are joined into a new 10
Two individual gases held in containers are joined into a new 10.0 litre container. What is the total pressure inside the new container?
2.0 L of O2 at an original pressure of kPa
3.00 L of Ne at an original pressure of kPa
Hint: what does a new larger container do to the partial pressure exerted by each gas?
PT = P1 + P2

12. P1V1 = P2V2
Oxygen: (202.6)(2.00) = P2 (10.0) P2 = 40.5 kPa
Neon: (303.9)(3.00) = P2 (10.0) P2 = 91.2 kPa
Need to use the correct Law to find the partial pressure for each gas in the new container
PT =
PT = kPa

13. CAN YOU / HAVE YOU? C11-2-07 UNITS AND RELATIONSHIPS
Describe the various units used to measure pressure and convert between units.
Include: atmospheres, kilopascals, millimetres of mercury
Experiment to develop the relationship between the pressure and volume of a gas using visual, numeric, and graphical representations.
Include: Boyle’s Law
Experiment to develop the relationship between the volume and temperature of a gas using visual, numeric, and graphical representations.
Include: Charles’ Law, Absolute zero, Kelvin scale, Ideal gas
Develop the relationship between the pressure and temperature of a gas using visual, numeric, and graphical representations.
Include: Gay-Lussac’s Law, Dalton’s Law
Vocabulary & Concepts 
Partial pressure