2. Gay-Lussac’s Gas Law

3. Gay-Lussac’s Law Joseph Louis Gay-Lussac in 1802 made reference in his paper to unpublished work done by Jacques Charles. Charles had found that oxygen, nitrogen, hydrogen, carbon dioxide, and plain air expand to the same extent over the same 80 degree interval.

4. Gay-Lussac’s law: The Volume of a sample of gas at constant pressure will vary directly with temperature. Temperature & pressure –As P  then T  –At constant V, n Remember all Temperatures must be in KELVIN

5. Gay-Lussac’s law: 1) Consider a container with a volume of 22.4 L filled with a gas at 1.00 atm at 273 K. What will be the new pressure if the temperature increases to 298 K? = 1.09 atm

6. Gay-Lussac Gay-Lussac was no slouch in the area of ballooning. On September 16, 1804, he ascended to an altitude of 7016 meters (just over 23,000 feet - about 4.3 miles). This remained the world altitude record for almost 50 years.

7. A Problem Blow up a balloon, measure its volume then take it to the top of Mt. Davis. Explain what would happen to its volume. What variables would you need to use to measure the change? How do those variables change as you go up to the top of Mt. Davis?

8. Now What? PV = k 1 V/T = k 2 P/T = k 3  If we combine all of the relationships from the 3 laws covered thus far (Boyle’s, Charles’s, and Gay- Lussac’s) we can develop a mathematical equation that can solve for a situation where 3 variables change :

9. Combined gas law  The # of moles is held constant  Is used when you have a change in volume, pressure, or temperature  The # of moles is held constant  Is used when you have a change in volume, pressure, or temperature P 1 V 1 T 2 = P 2 V 2 T 1 P1V1P1V1 P1V1P1V1 T1T1 T1T1 = = P2V2P2V2 P2V2P2V2 T2T2 T2T2 OR