1 Graham’s Law Gases expand to occupy the volume that is available to it. This is Diffusion – movement from _____ concentration to _______ concentration. Diffusion occurs a different rates depending on the ______ of the gas. – T and P are _______ – A denser (“heavier”) gas diffuses ____ ______. – A less dense (“lighter”) gas diffuses _______. H2 = 2g/1 mol HCl = 36.45g/1 mol N2 = 28g/1 mol H2O = 18g/1 molCH4 = 44g/1 mol

2 Combined Gas Law Relates Temperature, Volume, and Pressure of a gas Combination of all 3 previous gas laws ___________________________________________ FORMULA: P 1 V 1 = P 2 V 2 T 1 T 2 (2)(20) = (4) V Cross multiply 2000 V2 = V2 = 4L (2.7)(14) = (5) (9) 345 T = 37.8 T2T2 = K

3 Determining Density of a Gas D = m/V For 1 mole of a substance – D = formula mass/ molar volume – Molar volume = 22.4 L Assume 1 mol of gas D = m v D = 44g (in 1 mole) 22.4 L (in 1 mole) D = 1.96 g/L D = m v 0.8 = m 22.4 m = g ( in 1 mole) So formula mass is g/mol

4 PV = nRT P(5.6) = (2)(0.082)(283) P = 8.29 atm PV = nRT (1)V = (3)(0.082)(273) V = L