Ideal Gas Law PV n RT Brings together

Ideal Gas Law PV = n. RT Brings together gas properties. Can be derived from experiment and theory.

Ideal Gas Equation Volume Pressure PV=n. RT No. of moles R = 0. 0821 atm L / mol K R = 8. 314 k. Pa L / mol K Kelter, Carr, Scott, Chemistry A Wolrd of Choices 1999, page 366 Universal Gas Constant Temperature

PV = n. RT P V T n R = = = pressure volume temperature (Kelvin) number of moles gas constant Standard Temperature and Pressure (STP) T = 0 o. C or 273 K P = 1 atm = 101. 3 k. Pa = 760 mm Hg 1 mol = 22. 4 L @ STP Solve for constant (R) PV n. T Recall: 1 atm = 101. 3 k. Pa Substitute values: (1 atm) (22. 4 L) (1 mole)(273 K) = R R = 0. 0821 atm L / mol K R = 0. 0821 atm L mol K or (101. 3 k. Pa) ( 1 atm) = 8. 31 k. Pa L mol K R = 8. 31 k. Pa L / mol K

Ideal Gas Law What is the volume that 500 g of iodine will occupy under the conditions: Temp = 300 o. C and Pressure = 740 mm Hg? Step 1) Write down given information. mass = 500 g iodine T = 300 o. C P = 740 mm Hg R = 0. 0821 atm. L / mol. K Step 2) Equation: PV = n. RT Step 3) Solve for variable V = n. RT P Step 4) Substitute in numbers and solve (500 g)(0. 0821 atm. L / mol. K)(300 o. C) V = 740 mm Hg V= What MISTAKES did we make in this problem?

What mistakes did we make in this problem? What is the volume that 500 g of iodine will occupy under the conditions: Temp = 300 o. C and Pressure = 740 mm Hg? Step 1) Write down given information. mass = 500 g iodine Convert mass to gram; recall iodine is diatomic (I 2) x mol I 2 = 500 g I 2(1 mol I 2 / 254 g I 2) n = 1. 9685 mol I 2 T = 300 o. C Temperature must be converted to Kelvin T = 300 o. C + 273 T = 573 K P = 740 mm Hg Pressure needs to have same unit as R; therefore, convert pressure from mm Hg to atm. x atm = 740 mm Hg (1 atm / 760 mm Hg) P = 0. 8 atm R = 0. 0821 atm. L / mol. K

Ideal Gas Law What is the volume that 500 g of iodine will occupy under the conditions: Temp = 300 o. C and Pressure = 740 mm Hg? Step 1) Write down given information. mass = 500 g iodine n = 1. 9685 mol I 2 T = 573 K (300 o. C) P = 0. 9737 atm (740 mm Hg) R = 0. 0821 atm. L / mol. K V=? L Step 2) Equation: PV = n. RT Step 3) Solve for variable V = n. RT P Step 4) Substitute in numbers and solve (1. 9685 mol)(0. 0821 atm. L / mol. K)(573 K) V = 0. 9737 atm V = 95. 1 L I 2

Ideal Gas Law What is the volume that 500 g of iodine will occupy under the conditions: Temp = 300 o. C and Pressure = 740 mm Hg? Step 1) Write down given information. mass = 500 g iodine T = 300 o. C P = 740 mm Hg R = 0. 0821 atm. L / mol. K Step 2) Equation: PV = n. RT Step 3) Solve for variable V = n. RT P Step 4) Substitute in numbers and solve (500 g)(0. 0821 atm. L / mol. K)(300 o. C) V = 740 mm Hg V= What MISTAKES did we make in this problem?