2Gas Laws UnitESSENTIAL QUESTIONSOBJECTIVESHow do gases respond to changes in pressure, volume, and temperature?Why do you suppose we study ideal gases?Why is the ideal gas law useful even though ideal gases do not exist?Describe three factors that affect gas pressureExplain the relationship and calculate problems between p, v, and t of a gasRelate the total pressure to the partial pressures of gases contained in a mixtureUse Graham’s diffusion rate to calculate the rate of diffusion of given gases.
3Chemcatalyst: ___.___ Write down 4 properties of gases: Give me 2 examples of gases:
4Pressure Conversions 1 atm = 101.3 kPa = 760 mmHg (torr) How can we write these as conversion factors?
5Do you know why torr and mmHg are the same? Evangelista Torricelli invented the first barometer using mercury!Torr is in honor of his work with pressure and measuring it!
6Pressure Conversions Write what you are given with its units Write the conversion factor nexta. Be sure to make sure you’re units cancel out!Multiply the top and multiply the bottom… then divideCheck SigFigs and units!!!
7Let’s try this one together: If you have 99.6 kPa, how many atm would that be?
8Try this one on your own: How many mmHg are in atm?
9WWLKD?What would Lord Kelvin do? With Temperature…
10Temperature Conversions For gas laws, we will be using KELVINSThe Kelvin scale is only positive!Absolute Zero = 0 KK = oC + 273oC = K - 273
11Let’s try these: How many kelvins are equal to 21.0 oC?
12Volume Conversions1000 mL = 1LHow many liters are in 545 mL?
13Standard Temperature and Pressure STPStandard Temperature and PressureTemperature: 0oCPressure: 1.00 atm
14Chemcatalyst:___.___ How many atmospheres are equivalent to 450 kPa? Show work and units! Try your best on Sig Figs!
16Pressure & VolumeWhat happened to the peep’s volume when the air was sucked out?What happened to the pressure as the air was being sucked out?What happened to the peep’s volume when air was let back in?
17Fill in the blanks:As the pressure _______________, the volume _______________.This is an ________ or ________ relationship.
18Boyle’s Law PV =K P1V1 = P2V2 P= Pressure (atm, Kpa, Pa, mmHg (torr)) K is a constant; so we can say the initial and final conditions are equalAs P increases, V decreases; As P decreases, V increasesP1V1 = P2V2P= Pressure (atm, Kpa, Pa, mmHg (torr))V= Volume (mL or L)
19Let’s try this one together: 5.00 L of a gas is at 1.08 atm. What pressure is obtained when the volume is 10.0 L?
20Try this one on your own: 2.50 L of a gas was at an unknown pressure. However, at standard pressure, its volume was measured to be 8.00 L. What was the unknown pressure?(x) (2.50 L) = (1.00 atm) (8.00 L)X = 3.20 atm
21Boyle’s Law PracticeIn small groups, no more than 3 complete problems in your packet on page 1Must show work on a separate sheet of paperWhat ever you do not finish is homeworkGood Luck
22Chemcatalyst:__.___If a balloon has 30.0L of gas at kPa, what is the volume, if the pressure is decreased to kPa?Show all work with units and try your best with Sig figs!
23Liquid Nitrogen & balloons Video!What happen to the balloon in liquid nitrogen and after the liquid nitrogen?What two factors were affected in this video?
24Charles’ Law V/T =K V= Volume (mL or L) T= Temperature (K) K is a constant; so we can say the initial and final conditions are equalAs V increases, T increases; As V decreases, T decreasesV= Volume (mL or L)T= Temperature (K)
25Let’s do this one together! A balloon is inflated at 24oC and has a volume of L. What is the volume when the balloon is heated to 58oC?
26Try this one on your own: If a sample gas occupies 6.80L at 325oC, what will the temperature be if the volume decreases to L?
27Charles’ Law Practice In pairs complete 1-3 in your packet on page 2 Show work on a separate sheet of paperYou will have 10 minutes to complete these 3 problems!
28AXE Can VideoWhat will happen to the AXE can when it is placed in a bon fire?How to fix a ping pong ball with chemistry?!
29Mini Lab Follow the procedure! Steam can be as harmful as boiling water
30Chemcatalyst: __.__ What’s happening in this video? https://www.youtube.com/watch?v=GcCmalmLTiU
31Gay-Lussac’s Law P/T =K P= Pressure (Kpa, atm, or mmHg (torr) K is a constant; so we can say the initial and final conditions are equalAs P increases, T increases; As P decreases, T decreasesP= Pressure (Kpa, atm, or mmHg (torr)T= Temperature (K)
32Let’s try this one together! An aerosol can has a pressure of 103 kPa at 25oC, if the can reaches a temperature of 928oC within a fire, what is the new pressure?
33Try this one on your own: The pressure in a car tire is 198 kPa at 27oC. After a long drive, the pressure is 225 kPa. What is the temperature in the tire?T2 = 340 K
35Chemcatalyst: ___.___ Write down the 3 gas laws and their equations Write each relationship too (Ie: pressure does this when volume does this)A given sample of air has a volume of 6.00 L at 101 kPa, what volume would it occupy at 25.0 kPa?
36Let’s combine them What do each one of these equations have in common? Do the places where P, V, T switch or change?
37Combined Gas Law Red- Boyle’s Law Blue- Charles’ Law Green- Gay-Lussac’s LawOrange- the COMBINED Gas LawHow many “knowns” will you have to have?
38Combined gas LawsThe volume of a gas-filled baggie is 30.0 L at 313 K and 153 kPa, what would the volume be at STP?
39Combined gas law worksheet Work on Page 3’s chart on the combined gas law in pairs or threes!
40Prepare for Quiz on: - Pressure conversions - Named Gas Laws - Combined Gas Laws **Can use given sheet with formulas!
41Chemcatalyst: ____.____ What does it mean for something to be ideal?
42Ideal GasesThe named gas laws had P, T, and V, but what about moles and mass?Does gas have mass?
43IDEAL GAS LAW Moles and Gases Chemist needed an equation with mass or moles!Introducing the…. (drum role)IDEAL GAS LAW
44PV = nRT Ideal Gas Law P= Pressure ( MUST be in atm or kPa) V= volume (MUST be in LITERS!)n= Number of moles (mols)R= Gas constantFor Atm =For kPa = 8.314T= Temperature (MUST be in KELVIN (K))
45Let’s do this one together: At 34oC, the pressure inside a nitrogen-filled tennis ball with a volume of L is 212 kPa. How many moles of nitrogen are in the tennis ball?
46Try this one on your own: When the temperature of a hollow sphere containing 685 L of helium is held at 621 K, the pressure is 1890 kPa. How many moles of helium are in this sphere?
47Ideal Gas Law PracticeWork in small groups (2-3 people) and complete the back page in your packet #’s 1-3Complete on a separate sheet of paper, show all workYou have 10 minutes to complete!!!
48Molar Mass Reminder: Calculate the molar mass for: CaCO3 Mg(NO3)2 g/molg/mol
49Ideal Gas Law with mass!A steel cylinder that has a volume of 20.0L with nitrogen gas inside has a pressure of 200. kPa and 28oC, how many grams is that nitrogen (N2)?WOOHOO WE DID IT!
50Ideal Gas LawTry the mass problems on the ideal gas law worksheet, page 4
51Chemcatalyst ___.___How do we smell things across the room?
52DiffusionTendency for molecules to move towards areas of lower concentration until uniform throughoutMove from high concentration to lower ones