1. Monday April 25 Today’s Bellwork: Have your Using Ideal Gas Law assignment out and ready to check.

2. I need soda cans!  Please bring me uncrushed aluminum soda cans

3. Agenda Today  Check/review Using Ideal Gas Law assignment  Introduce/Practice Combined Gas Law  Start Using Combined Gas Law assignment Tuesday  Check/review Using Combined Gas Law assignment  Review for Level 2 assessment  Review assignments that will be tracked for stamp sheet Wed/Thurs  Level 2 assessment  Check/review begin interventions or practice for Level 3 Friday  TBD  Introduce Gas Stoichiometry for those working to Level 4?

4. Using the Ideal Gas Law

5. Temperature If we use Celsius or Fahrenheit scales for the temperature we get a few strange out comes  When the temperature is negative we would predict a negative pressure  When the temperature of a gas is 0°C or 0°F, we would predict a pressure of 0atm. Since neither of these outcomes are reasonable, a new temperature scale had to be devised that did not have negative temperatures.

6. Temperature The rationale for Kelvin scale  Since cooling an object means the molecules slow down, there would have to be a minimum speed (0 m/s) and therefore a minimum temperature  This temperature is called absolute zero  Absolute zero is 273.15° below the freezing point of water  Conversion = ___°C + 273.15 = ___ K  Examples:  Room temperature (25° C) = 25°C + 273.15 = 298.15 K  A day in Death Valley (50°C) = 50° C + 273.15 = 323.15K  SO, is 50° twice as hot as 25°C?  If you wanted to make something twice as hot as 25° C, to what temperature would you have to heat it?  298.15K x 2 = 596.3 K

7. Using the Ideal Gas Law

14. Ideal vs. Combined Gas Law Ideal Gas Law (PV= nRT)  Use the ideal gas equation when you want to identify a missing variable within the same system  But what do you do when you want to compare the pressure, volume, moles, or temperature of two different systems, or the same system under different conditions ?  For example, when you change the temperature?

15. Ideal vs. Combined Gas Law Use the Combined Gas Equation

16. Combined Gas Law If I initially have a 1 mol of gas at a pressure of 12 atm, a volume of 23 liters, and a temperature of 200 K, and then I raise the pressure to 14 atm, add another mol of gas to 2 mol, and increase the temperature to 300 K, what is the new volume of the gas?

17. Combined Gas Law A gas that has a volume of 28 liters, a temperature of 45°C, and an unknown pressure has its volume increased to 34 liters and its temperature decreased to 35° C. If I measure the pressure after the change to be 2.0 atm, what was the original pressure of the gas?

18. Combined Gas Law A gas has a temperature of 14° C, and a volume of 4.5 liters. If the temperature is raised to 29°C and the pressure and mols of gas are not changed, what is the new volume of the gas?

19. Combined Gas Law Complete this assignment tonight, and be prepared to check, discuss, and/or ask questions about it in class tomorrow