Announcements Exam 4 on Chapters 7 & 8 one week from today. To join clicker to class today: Turn on the Clicker (the red LED comes on). Push “Join” button followed by “20” followed by the “Send” button (switches to flashing green LED if successful). Exam 4 on Chapters 7 & 8 one week from today. All study material for these chapters is posted on web site. Do not forget about the Lewis Tutorial, the VSEPR examples on Web site and the text site as well for more examples and pictures. Wear appropriate clothes to lab (no sandals, shorts, etc...)

Review Chapter 7 Pictorial determination of total dipole direction Quantitative dipole calculations using: µ = Qr Chapter 8: PV = nRT Solved for P = nRT/V Solved for V = nRT/P How this equation includes Boyle's and Charle's Laws.

PV=nRT Called Ideal Gas Law P = pressure, we will use unit of atm, but can also be in mmHg=Torr (1 atm = 760 Torr) Pa = Nm-2 (1 atm = 101325 Pa) bar = 105 Pa (1 atm = 1.01325 bar) V = the volume occupied by the gas n = the number of moles of gas in the volume R = the gas constant = 0.082058 L•atm•mol–1K–1 T = temperature in Kelvin Model works well for gases near room temperature and 1 atm.

Dalton’s Law of partial pressures Ptot = P1 + P2 + … = (n1 + n2 + …)RT/V Pi/Ptot = mole fraction of gas i, Written as Xi Pi = XiPtot ∑i Xi = 1 or X1 + X2 + X3+ ... = 1