(a) Calculate the mass of nitrogen present in a volume of 3000 cm3 if the gas is at 22.0°C and the absolute pressure of 2.00 X 10-13 atm is a partial vacuum easily obtained in laboratories. (b) What is the density (in kg/m3) of the N2?

Solution 19E Step 1: We have the density of a gas PV = nRT p pressure of gas V volume of gas R universal real gas constant 8.3145 J/mol.k T absolute temperature gas constant n number of molecules Step-2: Given pressure P = 2.03 × 10 8Pa Temperature T = 273 + 22 = 295 K Volume V = 3.00 × 10 m 3 3 (a). PV = nRT n = PV /RT 8 3 3 n = (2.03 × 10 Pa)(3.00 × 10 m )/(8.3145 J/mol.k)(295 K) 14 n = 2.48 × 10 mol. m = nM m = (2.48 × 10 14)(2.80 × 103kg/mol) m = 6.95 × 1016 kg