Question

A 30.21 g sample of Ar (Argon) gas has a volume of 900 mL at a temperature of 200°C.

i. Calculate the pressure using the Ideal Gas Law.

ii. Calculate the corrected pressure using the Van der Waals Equation.

a=1.336 atm×L2 mol2 b=0.03201 L mol

Answer 1

Molecular weight of Ar = 40 g/mole

30.21 g of Ar = 30.21/40 mole

=0.755 mole (n)

Volume,V = 900mL

=.9L

Temperature,T = 200°C

= 473K

Pressure,P = nRT/V where R=0.082

=32.54 atm

Now according to Vander Waals equation,

Pressure,P= (nRT/(V-nb))-(n²a/V²)

= 32.49 atm