Gas Laws Chapter 14. Kinetic Molecular Theory of Gases No attraction/repulsion between particles...
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Transcript of Gas Laws Chapter 14. Kinetic Molecular Theory of Gases No attraction/repulsion between particles...
Kinetic Molecular Theory of Gases
No attraction/repulsion between particlesVolume of particles is 0Constant random motionElastic collisionsEqual kinetic energy at same temperature
Things to Remember…
Units of Pressure1 atm = 101.3 KPa = 760 mm Hg = 14.7 psi= 760 Torr
Temperature ConversionK= oC + 273
Practice
A gas at 0.8atm is compressed from 3L to 1.2L. What is the resulting pressure in atm? In KPa?
What About Pressure and Temperature?
At constant volume, pressure and temperature are directly related
P1/T1 = P2/T2
Practice
A gas is pressurized in a 2L bottle to 57 KPa. If the bottle is heated from room temperature (298K) to 312K, what will be the resulting pressure in KPA? In mm Hg?
Combined Gas Law
A closed gas system initially has pressure and temperature of 1.56atm and 629K with the volume unknown. If the same closed system has values of 195torr, 9940mL and 523K, what was the initial volume in L?
Ideal v. Real Gases
Particles of real gases have volume and experience attractive and repulsive forces
They’re the same except at:EXTREMELY LOW T
Kinetic energy decreases. Particles are close enough to allow for intermolecular bonding.
EXTREMELY HIGH P Compressed gases (gas particles are so close that there
is little space between them so their own volume becomes significant)
IDEAL GAS LAW
PV=nRT n=moles
n=m/MM m=(n)(MM) MM=m/n
Ideal Gas ConstantsR= 0.0821 L*atm/mol*KR= 8.314 L*KPa/mol*KR= 62.4 L*mm Hg/mol*K
Avogadro’s Principal
Equal volumes of gases at the same temperature and pressure contain an equal number of particles.I mole of any gas at STP = 22.4 LSTP (standard temperature and pressure)=0oC and 1atm
What volume does 24g of oxygen occupy at STP?
22 8.161
4.22
32
124 OLmole
L
g
molegO
Gas Stoichiometry – STP Conditions
OHOH 222 22
222
222 0.10
1
4.22
1
2
4.22
10.5 LH
molH
L
molO
molH
L
moleOLO
Volume-Volume problems (two substances have to be gases)
Determine the volume of hydrogen gas needed to completely react with 5.0L of oxygen gas to form water at STP.
Volume-Mass problems (at least one substance has to be a gas)
Calculate the volume of oxygen gas at STP that is required to complete react with 52.0g or iron.
322 234 OFeOFe
22
2 7.151
4.22
4
3
8.55
10.52 LO
molO
L
molFe
molO
gFe
moleFegFe
STP vs. Non-STP Gas Stoichiometry Problems
Calculate the volume of oxygen gas at STP that is required to completely react with 52.0g of iron.
322 234 OFeOFe
22
2 7.151
4.22
4
3
8.55
10.52 LO
molO
L
molFe
molO
gFe
moleFegFe
VS.
Calculate the volume of oxygen gas that is required to completely react with 52.0g of iron at 85kPa and 273K.
22 6.18
85
1
1
27331.8
4
3
8.55
10.52 LO
kPa
K
molK
kPaL
molFe
molO
gFe
moleFegFe