gas laws why gases behave as they do. factors affecting gases pressure atmosphere mm hg, torr psi...
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Gas Laws
Why Gases Behave As They Do
Factors Affecting Gases• Pressure
Atmospheremm Hg, Torrpsi (pounds per square inch; #/in2)Paschal (N/ m2)
• VolumeLiter
• Temperature (Kelvin)• Amount
Mole
Pressure Equivalencies
• 1 Atmosphere =• 760 mm Hg =• 760 torr =• 101.3 kPa =
1 paschal = 1 Newton/ meter2
• 14.7 psi
Ideal Gas Law
• Applies to kinetic-molecular theory gases– Real gases at high temperatures & low pressures
• P V = n R TP = Pressure (SI unit is Paschal)V = Volume in Litersn = # molesR = gas constant (adjusts to units of pressures)T = Temperature in Kelvin {273.15 + oC}
Variations of PV = nRT
• Boyle’s LawP1 V1 = P2 V2
• Charles’ LawV1/ T1 = V2/ T2 or V1 T2 = V2 T1
• Gay-Lussac’s LawP1/ T1 = P2/ T2 or P1 T2 = P2 T1
• Combined Gas Law P1 V1/ T1 = P2 V2/ T2 or P1 V1 T2 = P2 V2 T1
Other Values of Importance• Dalton’s Law of Partial Pressures
Total pressure of a gas = S partial pressures• Graham’s Law of Effusion
½ MAnA2 = ½ MBnB
2 {M = molar mass; = nvelocity}
The lighter gas must effuse faster.Rate of effusion of A/ rate of B = √MB / √MA
• Standard Temperature & Pressure (STP)1 atmosphere; 0o C = 273 K
• Gas Molar Constant = 22.41410 Liters/ mole
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