V n Avogadros Principle b Equal volumes of gases contain equal numbers of moles at the same temp & pressure true for any gas
PV T VnVn PV nT Ideal Gas Law = k UNIVERSAL GAS CONSTANT R=0.0821 L atm/mol K = R Merge the Combined Gas Law with Avogadros Principle:
Ideal Gas Law UNIVERSAL GAS CONSTANT R=0.0821 L atm/mol K PV=nRT
GIVEN: P = ? atm n = 0.412 mol T = 16°C = 289 K V = 3.25 L R = 0.0821 L atm/mol K WORK: PV = nRT P(3.25)=(0.412)(0.0821)(289) L mol L atm/mol K K P = 3.01 atm Ideal Gas Law Problems b What is the pressure in atmospheres of 0.412 mol of He at 16°C & occupying 3.25 L?
GIVEN: V = ? n = 85 g T = 25°C = 298 K P = 850 Torr = 1.12atm R = 0.0821 L atm/mol K Ideal Gas Law Problems b Find the volume of 85 g of O 2 at 25°C and 850 Torr. = 2.7 mol WORK: 85 g 1 mol = 2.7 mol 32.00 g PV = nRT (1.12)V=(2.7) (0.0821)(298) atm mol L atm/mol K K V = 59.0 L