Answer to Question #323776 in General Chemistry for tori

Question

Helium gas is contained in a tank with a pressure of 11.0 MPa. If the temperature inside the tank is 22.0 ºC and the volume of the tank is 15.8 L, determine the mass, in grams, of the helium in the tank.

Answer 1

pV = nRT

p = 11.0 MPa = 11×10⁶ Pa = 11×10⁶ × 9.87×10^-6 atm = 108.57 atm

T = 22.0°C = (22.0 + 273.15) K = 295.15 K

n = pV/RT = (108.57 atm)(15.8 L) / (0.0821 L atm/mol K)(295.15 K) = 70.79 mol

m(He) = n(He) × Mr(He) = 70.79 mol × 4.00 g/mol = 283.17 g