Chapter 5 Gases

Pressure barometer – measures atmospheric pressure manometer – measures gas pressure units of pressures are: mmHg, Pa, atm and Torr 760 mmHg = 760 Torr = 1 atm = 101.3 kPa Page 235: # 37 a-c

Boyle’s Law PV = k where K is called Boyle’s constant P1V1 = P2V2 holds true only at low pressures Look over example 5.3 on page 195 Page 235: #43

Charles’ Law V1/T1 = V2/T2 temperature must be in Kelvins Page 236: # 44

Gay-Lussac’s Law P1/T1 = P2/T2 Temperature must be in Kelvins

Avogadro’s Law V1/n1 = V2/n2 Page 236: # 45 & 46

Combined Gas Law P1V1/T1 = P2V2/T2 Temperature must be in Kelvins

Ideal Gas Law PV = nRT R = 0.8206 L atm K-1 mol-1 useful only at LOW pressure and HIGH temperatures (this will be an AP question) Page 236: #49

Gas Stoichiometry Page 237: #67

Gas Density & Molar Mass MM = dRT/P Page 237: # 77 & 79

Dalton’s Law …of partial pressures Ptotal = P1 + P2 + … look over example 5.16 on page 212 Page 237: # 72

Kinetic Molecular Theory All particles are in constant, random motion All collisions between particles are elastic The volume of the gas particles is negligible Average kinetic energy is proportionate to it Kelvin temeperature Average velocity of gas molecules = root mean square velocity = urms = 3RT/MM R = 8.31 J/K mol Page 240: # 109

Effusion & Diffusion diffusion – mixing of gases effusion – passage of a gas through a tiny hole into an evacuated chamber Graham’s law : rateA/rateB = MMB/MMA Page 240: # 111

Real Gases act like ideal gases at LOW pressures and HIGH temperatures look over van der Waals Equation on page 225