States of matter solids liquids gases fixed shape shape of container independent Kinetic model of gases very small volumes in constant motion “elastic” collisions

Pressure = force force = collisions of particles area atmospheric pressure 14.7 lbs sea level ft2 vacuum = absence of gas particles

atmospheric pressure barometer Torricelli 760 mm Hg = 1 atm 760 mm Hg = 760 torr 760 mm Hg = 1.01325 x 105 Pa could use water 10,300 mm H2O 34 feet

Boyle’s Law Pressure Volume PV = constant

Boyle’s Law Pressure Volume PV = constant P1V1 = P2V2 A sample of Cl2 has a volume of 946 mL at a pressure of 726 mm Hg. If the volume is reduced to 154 mL, calculate the pressure. (726 mm Hg) (946 mL) = P2 (154 mL) P2 = 4460 mm Hg 4460 mm Hg  760 mm Hg/atm = 5.97 atm

Charles’s Law Volume Temperature V = constant T Kelvin V = 0 T = -273.15oC

Charles’s Law Volume Temperature V1 T1 V2 T2 = 273.15 K A container is filled with N2 in an ice bath (0o C) Its volume is 58.7 mL. It is then put in a bath of boiling isopropanol. Its volume goes to 76.4 mL. What is the b.p. of isopropanol? 58.7 mL 76.4 mL T2 = 355.5 K = 273.15 K 82.3o C T2

Avogadro’s Law Volume moles Gay-Lussac 2 H2 + O2  2 H2O (g) Law of combining volumes 200 mL H2 100 mL O2 200 mL H2O Avogadro equal volumes of gases = equal numbers of molecules 1 mol gas = 6.023 x 1023 particles = 22.4 L at standard Temperature and Pressure 0.0oC (273.2 K) 1 atm (760 torr)

Ideal Gas Law Boyle PV = constant P V = n R T Charles V R = ideal gas constant = constant T = 0.08206 L atm Avogadro V = constant mol K n two types of problems 1. Predicting properties of a system PV = nRT no changes 2. Changing conditions P1V1 = R = P2V2 n1T1 n2T2

Calculate the pressure of 80.10 g. of CO2 gas in a 5000 mL flask at 70.0oC 1. Predicting properties of a system PV = nRT P = V = 5000 mL = 5.00 L n = 80.10 g ÷ 44.01 g/mol = 1.82 mol T = 70.2 + 273.15 = 343.2 K (P) (5.00 L) = (1.82 mol) (0.08206 L atm) ( 343.2 K) mol K (P) = 10.25 atm

A small bubble (2.1 mL) rises from the bottom of a lake, where the temperature is 8.00C and the pressure is 6.4 atm, to the surface where the temperature is 25.0oC. What is the volume of the bubble at the surface? initial final P1= 6.4 atm P2= 1.0 atm V1 = 2.1 x 10-3 L V2 = 14 mL T1 = 281.15 K T2 = 298.15 K 2. Changing conditions P1V1 n1T1 = R = n2T2 P2V2