Question

At high pressures, real gases do not behave ideally. Calculate the pressure exerted by 39.5 g H2 at 20.0°C in a 1.00 L container assuming in Part 1 non-ideal behavior and in Part 2 ideal behavior. 7th attempt Part 1 Use the van der Waals equation and data in the hint to calculate the pressure exerted. 862 atm Part 2 Now, calculate the pressue excerted assuming that the gas behaves as an ideal gas.

Answer 1

part 1 ,

vander waals equation

       (P+an^2/V^2)(V-nb) = nRT

     a = 0.2453 (L2bar/mol2) , b = 0.02651 L/mol

n = no of mol of H2 gas = 39.5/2 = 19.75 mol

V = 1 L

R = 0.0831 l.bar.k-1.mol-1

T = 20 c = 293.15 k

(P+(0.2453*19.75^2/1^2))(1.0-19.75*0.02651) = 19.75*0.0831*293.15

P = pressure of gas = 914.18 bar

                     = 902.22 atm

part 2, from ideal gas equation.

PV = nRT

P = pressure of gas = ?

n = no of mol of H2 gas = 39.5/2 = 19.75 mol

V = 1 L

R = 0.0821 l.atm.k-1.mol-1

T = 20 c = 293.15 k     

(P*1) = (19.75)*0.0821*293.15

P = 475.33 atm