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Three More Laws. P 1 V 1 T 1 n. P 2 V 2 T 2 n. =. A. Ideal Gas Law. The 4 th variable that considers the amount of gas in the system is. Equal volumes of gases contain equal numbers of moles (varies directly w/V). Add moles to the combination gas law. A . Ideal Gas Law.
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P1V1 T1 n P2V2 T2 n = A. Ideal Gas Law • The 4th variable that considers the amount of gas in the system is • Equal volumes of gases contain equal numbers of moles (varies directly w/V). • Add moles to the combination gas law
A. Ideal Gas Law • You can calculate the # of n of gas at standard values for P, V, and T PV Tn = R (1 atm)(22.4L) (273K)(1 mol) = R UNIVERSAL GAS CONSTANT R= 0.0821 atm∙L/mol∙K R=8.315 kPa L/molK You don’t need to memorize this value!
A. Ideal Gas Law PV=nRT UNIVERSAL GAS CONSTANT R= 0.0821 atm∙L/mol∙K R=8.315 kPa L/molK You don’t need to memorize these values!
A. Example Problems 1. At what temperature will 5.00g of Cl2 exert a pressure of 900 mm Hg at a volume of 750 mL? 2. Find the number of grams of CO2 that exert a pressure of 785 mm Hg at a volume of 32.5 L and a temperature of 32 degrees Celsius. 3. What volume will 454 g of H2 occupy at 1.05 atm and 25°C.
B. Graham’s Law • Diffusion • The tendency of molecules to move toward areas of lower concentration. • Ex: air leaving tire when valve is opened • Effusion • Passing of gas molecules through a tiny opening in a container
B. Graham’s Law Tiny opening Diffusion Effusion Which one is Diffusion and which one is Effusion?
C. Dalton’s Partial Pressure Law • The total pressure of a mixture of gases equals the sum of the partial pressures of the individual gases. Ptotal = P1 + P2 + P3 +...
C. Dalton’s Law • Exmple problem: 1. Air contains oxygen, nitrogen, carbon dioxide, and trace amounts of other gases. What is the partial pressure of oxygen (PO2) at 101.3 kPa of total pressure if the partial pressures of nitrogen, carbon dioxide, and other gases are 79.10 kPa, 0.040 kPa, and 0.94 kPa. PO2 = Ptotal – (PN2 + PCO2 + Pothers) = 101.3 kPa – (79.10 kPa + 0.040 kPa + 0.94 kPa) = 21.22 kPa