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CHEM 433 - 9/16/11. II. Gases —> Intro and definitions. (1.1) A. Ideal Gases —> The ideal gas Law (1.2) —> “Equations of “State” —> Using the Ideal Gas Law —> Dalton’s Law: Mixtures READ: Chapter #1 HW: HW #2 via email. Gas : A form of matter that fills any container. - PowerPoint PPT Presentation
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CHEM 433 - 9/16/11
II. Gases
—> Intro and definitions. (1.1)
A. Ideal Gases
—> The ideal gas Law (1.2)
—> “Equations of “State”
—> Using the Ideal Gas Law
—> Dalton’s Law: Mixtures
READ: Chapter #1
HW: HW #2 via email
Gas: A form of matter that fills any container.
Features : - Molecules in “ceaseless random motion”.- Speeds increase with temperature.- Molecules widely separated except during collision.- Paths “largely unaffected” by IMF. (IDEAL = NO IMF)
Physical State: The “condition” of the system as specified by its physical properties. The State of a pure gas is specified by p, V, T, and n.
Equation of State: An Equation that relates p,V,T (e.g. p = f(n,V,T)).
Perfect (or Ideal) Gas: Obeys: pV=nRT or (p=nRT/V)
Pressure: Force/Area. SI Unit: Pascal (Pa) = N/m2.
http://en.wikipedia.org/wiki/Pressure_measurement
Others: Atmospheres (atm), bar, & Torr (=mmHg). (1 atm = 760 Torr = 1.01325 bar = 1.01325 x 105 Pa).
Standard Pressure: 1 bar (p°)
Mechanical Equilibrium: Equal pressures (e.g. 2 gases separated by a movable piston).
Temperature: A property that indicates the direction of heat flow.
Thermal Equilibrium: Temperatures are equal (no heat flow).
Thermodynamic Temperature Scale: T(K) = Q(°C) + 273.15
0th Law of Thermodynamics:
If A ~ B, and B ~ C —> A ~ C (~ = in Thermal EQ w/)
Diathermic Boundary: Change of state can occur upon contact (heat transfer allowed).
Adiabatic Boundary: No change of State occurs upon contact (no heat transfer).
The unofficial mascot of CHEM 433:
The frictionless movable pistonF.M.P.
Boyle’s Law: PV = const.or: p = 1 / V(constant T,n)
Charles’ Law(s) : P ~ T V ~ T
(constant n, and p or V)
Avagadro’s Principle:
V ~ n
(constant T, p)
What is the volume of 1 mol of gas at:
a) STP (T=0°C and p = 1 atm) ?
b) SATP (T=298.15K, p=1 bar)?
a) 22.4 L
b) 24.8 L
Using the Combined Gas Law:
Calculate the final temperature when 1 mol of gas a SATP is compressed from 24.8 To 12.4 L and the pressure increases from 1.0 to 2.0 bar?
THE SAME - about 298K
P1V1T1
P2V2T2
Using Dalton’s Law:
Calculate PN2, PO2 and PAr in the atmosphere, assume PTOT = 1.00 atm.
moles
PN2 = 0.78 atm, PO2 = 0.21 atm, PAr = 0.0093 atm
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