gas laws chapter 10 p303 kmt kinetic molecular theory 1. gases consist of particles far apart....
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GAS Laws chapter 10 p303 KMT
Kinetic Molecular Theory1. Gases consist of particles far apart.
2. Collisions between particles are elastic.elastic meaning = no net loss of
KE
3. Gas particles are in constant, rapid, random motion
4. No forces of attraction or repulsion between gas particles.
5. Average KE of a gas depends on Temperature of gas.
Ideal Gases: an imaginary gas that
perfectly fits all assumptions of KMT.
(Noble gases) closest thing to it
Real Gases: does not behave completely
to the laws and theories of the KMT.
Need to know 4 items for understanding Gases
Volume: liters and milliliters
Temperature: Kelvin K K = 273 + oC convert 42oC =
126oC=212oC=
Zero degrees Kelvin = absolute zero
coldest temperature never reachable
Need to know 4 items for understanding Gases
Volume: Temperature:
# of moles or molecules
avagadro’s number 6.022 x 1023 molecules per mole
22.4 liters per mole@ STP
STP === standard temperature pressure(OoC or 273K( (1atm)
P. 310 Pressure: atm atmosphere of pressure
1 atm = 760 mm Hg = 760 torr = 101.3 kpaShow overhead 49
Sea level pressure = 1 atm or 760mm Hg or 101.3 kpa
STP === standard temperature pressure
(OoC or 273K) (1atm)
Average pressure in Denver Colorado is 0.083atm.
Express in mm Hg and kpa
Boyles Law: keeping temperature same
pressure up = volume down
pressure down = volume up
P1V1 = P2V2
When cap comes off …pressure goes down
= volume goes up.
Video under pressure
Charles Law: keeping pressure same
temperature up volume up temperature down volume down
Balloon in freezer vs balloon next to heatCar tires in winter vs. tires in summer
V1 = V2 T1 T2
Video wok/baloons
Gay-Lussac’s law : keeping volume same
Temperature up = pressure up
Temperature down = pressure down
Throw hair spray can in fire
P1 P2
T1 T2
video crushing cans
What happens to the tire as you add pressure?
Why are weather balloons under inflated?
P. 321 Combined Gas Laws: all 3 put together
P1V1 = P2V2
T1 T2Worksheet 10.33
1) If I initially have a gas at a pressure of 12 atm, a volume of 23 liters, and a temperature of 200k, and then I raise the pressure to 14 atm and increase the temperature to 300 K, what is the new volume of the gas?
3) A gas that has a volume of 28 liters, a temperature of 45c, and an unknown pressure has its volume increased to 34 liters, and its temperature decreased to 35c. If I measure the pressure after the change to be 2.0 atm, what was the original pressure of the gas?
Combined Gas Law
P1V1 = P2V2
T1 T2
Ideal Gas Law
Involves P,V,T & …number of moles of gas
PV = nRTAll units must be : P = atm
V = liters
T = Kelvin
n = #of moles
R = .0821 liters x atm
moles x K R is a constant …….. Like pi is a constant 3.14 ws.11.21
Ws. 11.21
1. If I have 4 moles of a gas at a pressure of 5.6 atm and a volume of 12 L, what is the temperature?
2. If I have an unknown quantity of gas at a pressure of 1.2 atm, a volume of 31 liters, and a temperature of 87c, How many moles of gas do I have?
3. If I contain 3 moles of gas in a container with a volume of 60 liters and at a temperature of 400K, what is the pressure inside the container?
Dalton’s Law of Partial Pressure
Total pressure of a mixture of gases =
sum of partial pressure of the component gases. Ptotal = P1 + P2 + P3 + P4 …
Overhead 48,50
Worksheet 10.38 problems 1,2,3
Diffusion & Effusion p. 351
KMT: 4- No significant forces of attraction or repulsion between gas particles
So…..gas particles can flow easily past one another
3- Gas particles are in constant, rapid, random
motion. They have KE.
So…..random motion of gas particles causes the gas particles to evenly mix.
Effusion = movement of a material through a tiny opening in a container.
“How fast a perfume comes out of a bottle”
Diffusion = movement of one material through another
material. Overhead 56
“Cooking cookies in the kitchen…others can smell it upstairs in the bedroom.”
Rate of Diffusion depends on mass of particles
---Skinny people can run faster than fat people---
---So can molecules---
Lighter molecule diffuse faster than heavy molecules @ STPoverhead 54
Of the following molecules which would diffuse faster?
l. Oxygen or Neon
2 Sulfur dioxide or carbon dioxide
3. Chlorine gas or krypton gas
Ch. 11 Gas Laws p. 333
Stoichiometry of gases
1 mole of oxygen has 6.022 x 1023 molecules
1 mole of hydrogen has 6.022 x 1023 molecules
1 mole of oxygen has a mass of 32 grams
1 mole of hydrogen has a mass of 2 grams(because diatomic)
Avagadro has a standard molar volume for gases
1 mole of any gas has a volume of 22.4 liters
Ws. 11.11
Ws.11.11
1. A chemical reaction produces 0.068 mol oxygen gas. What volume in liters is occupied by this gas at STP?
2. A sample hydrogen gas occupies 14.1 L at STP. How many moles of the gas are present?
3. At STP a sample of neon gas occupies 550 cm3. How many moles of neon gas does this represent?
Add more stoi problems