Transcript Document 7463607

GAS Laws
chapter 10
p303
1.
KMT
Kinetic Molecular Theory
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
convert
K
K = 273 + oC
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
1 atm at OoC or 273K
P. 310
Pressure: atm
atmosphere of pressure
1 atm = 760 mm Hg = 760 torr = 101.3 kpa
Show overhead 49
Sea level pressure = 1 atm or 760mm Hg or 101.3 kpa
STP === standard temperature pressure
1 atm at OoC or 273K
Average pressure in Denver Colorado is 0.083atm.
Exress 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
temperature down
volume up
volume down
Balloon in freezer vs balloon next to heat
Car tires in winter vs. tires in summer
V1 = V2
T1 T2
Video
wok/baloons
Gay-Lussac’s law : keeping volume same
Temperature up
Temperature down
=
=
pressure up
pressure down
Throw hair spray can in fire
P1
T1
P2
T2
video crushing cans
Why are weather
balloons under
inflated?
Combined Gas Laws: all 3 put together
P1V1
T1
=
P2V2
T2
Worksheet 11.0
1)A scuba diver at the beach has his 24 L air tank sitting outside in a
temperature of 30 degree Celsius and the tank pressure registers at
12atm. As he dives down into the ocean the temperature of the water
and tank drop to 10 degrees Celsius. What is the new pressure of the
scuba tanks?
Combined Gas Law
P1V1 = P2V2
T1
T2
Ideal Gas Law
Involves P,V,T & …number of moles of gas
PV = nRT
All 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
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 …
1.
If 5 gases in a cylinder each exert 1atm, what is the total
pressure exerted by the gases?
2. Three samples of gas each exert 740mm Hg in separate
2-L tanks. What pressure do they exert if they are all
placed in a single 2-L tank.
3. A mixture of four gases exerts a total pressure of 860
mmHg. Gases A and B each exert 220 mmHg. Gas C
exerts 110mmHg. What pressure is exerted by gas D?
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.
Diffusion =movement of one material through another material.
“Cooking cookies in the kitchen…others can
smell it upstairs in the bedroom.”
Rate of Diffusion depends on mass
---Skinny people can run faster than fat
people-----So can molecules---
Lighter molecule diffuse faster than heavy molecules @ STP
overhead 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
List the following gases in order of increasing rate of
effusion.
(a) He
(b) Xe
(c) HCl
(d)Cl2
The two gases in the figure below are simultaneously
injected into opposite ends of the tube. They should just
begin to mix closet to which labeled point?
H2S
0
of
5
SO2
1. A
2. B
3. C
0%
1
0%
2
0%
3
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
A chemical reaction produces 0.068 mol oxygen
gas. What volume in liters is occupied by this gas
at STP?
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The volume of a sample of hydrogen is
798mL and it exerts 621mmHg pressure at
5.00oC. What volume does it occupy at
STP?
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of
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At STP a sample of neon gas occupies
550 cm3. How many moles of neon gas
does this represent?
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of
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When the pressure exerted on a confined gas at
constant temperature is doubled, the volume of the
gas is…
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1.
2.
3.
4.
Doubled
Halved
Tripled
quartered
0%
1
0%
0%
2
3
0%
4
Fluorine gas reacts violently with water to
produce hydrogen fluoride and ozone. What
volume of HF would be produced by the
complete reaction of 36Lof fluorine gas?
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