ideal gas law and calculating presure

Question

1.A sample of krypton gas collected at a pressure of 954 mm Hg and a temperature of 277 K has a mass of 84.6 grams. The volume of the sample is ______ L.

2.A 5.46 gram sample of nitrogen gas has a volume of 868 milliliters at a pressure of 3.49 atm. The temperature of the N₂ gas sample is  ________°C.

Answer 1

Ideal gas law: PV = nRT

P = 954 mm Hg

V = ?

n = moles = 84.6 g x 1 mol/83.798 g = 1.01 moles

R = 62.36 L*mmHg/K*mol

T = 277K

plug these values into the ideal gas equation and solve for V

For number 2, moles (n) of nitrogen = 5.46 g x 1 mol/28g = 0.195 moles. Convert volume to liters (0.868 L), use R = 0.0821 L*atm/K*mol, and plug into the ideal gas equation and solve for T. Subtract 273 to obtain ºC.