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CHEM 433 - 9/16/11

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.

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CHEM 433 - 9/16/11

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  1. 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

  2. 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).

  3. 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).

  4. The unofficial mascot of CHEM 433: The frictionless movable piston F.M.P.

  5. Boyle’s Law: PV = const. or: p = 1 / V (constant T,n)

  6. Charles’ Law(s) : P ~ T V ~ T (constant n, and p or V)

  7. Avagadro’s Principle: V ~ n (constant T, p)

  8. What is the volume of 1 mol of gas at: STP (T=0°C and p = 1 atm) ? SATP (T=298.15K, p=1 bar)? 22.4 L 24.8 L

  9. 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

  10. 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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