Gas Laws Review

Volume Decreases, Pressure Increases Boyle’s Law The volume of a sample of gas is inversely proportional to its pressure, if temperature remains constant Volume Decreases, Pressure Increases Volume Increases, Pressure Decreases

Boyle’s Law Formula-Reference Table P1 V1 = P2 V2

Example A sample of gas collected in a 350 cm3 container exerts a pressure of 103 kPa. What would be the volume of this gas at 150 kPa of pressure? (Assume that the temperature remains constant.) P1 V1 = P2 V2 P1 = 103 kPa V1 = 350 cm3 P2 = 150 kPa V2 = x (103)(350) = (150)(x) V2 = 240.3 cm3

Charles Law The volume of a sample of gas is directly proportional to its Kelvin temperature, if pressure remains constant. Volume Increases, Temperature Increases Volume Decreases, Temperature Decreases

Charles Law Formula-Reference Table V1 / T1 = V2 / T2 V = Volume of gas (L) T = Temperature of gas (K)

Example 4.40 L of a gas is collected at 50.0°C. What will be its volume upon cooling to 25.0°C? V1 / T1 = V2 / T2 V1 = 4.40 L T1 = 323 K V2 = x T2 = 298 K K = °C+ 273 (Reference Table) (4.40)/(323) = (x)/(298) V2 = 4.09 L

Combined Gas Laws-Reference Table P1V1 / T1 = P2V2 / T2 V = Volume of gas (L) T = Temperature of gas (K)

Example P1 = 12 atm V1 = 23 L T1 = 200 K P2 = 14 atm V2 = ? T2 = 300 K If I initially have a gas at a pressure of 12 atm, a volume of 23 liters, and a temperature of 200 K, and then I raise the pressure to 14 atm and increase the temperature to 300 K, what is the new volume of the gas? P1 = 12 atm V1 = 23 L T1 = 200 K P2 = 14 atm V2 = ? T2 = 300 K (12)(23) = (14)(V2) 200 300 V2 = 29.57 L

Equation is on the Reference Table Ideal Gas Law Equation Equation is on the Reference Table

Gas Constant Value See Reference Table L atm mole K 0.0821 L mmHg mole K 62.4 8.314 L kPa mole K What is the difference between each constant?

Example #1 How many moles of N2 are in a 750 mL vessel at 26 degrees Celsius and 625 mm Hg? P = 625 mmHg V = 750mL  0.750 L n = ? R = 62.4 L mmHg mol K T = 26°C  299 K (625)(0.75) = (n)(62.4)(299) 468.75 = (18657.6)(n) N = 0.025 mol

Dalton’s Law Formula See Reference Table

Dalton’s Law