Question

A. Use the van der Waals equation to calculate the pressure exerted by 1.205 mol of Cl2 in a volume of 4.990 L at a temperature of 286.5 K .

B. Use the ideal gas equation to calculate the pressure exerted by 1.205 mol of Cl2 in a volume of 4.990 L at a temperature of 286.5 K .

Answer 1

Answer – A) We are given, moles of Cl₂ = 1.205 moles , volume = 4.990 L ,     T = 286.5 K

We know the van der Waals equation-

(P + n²a / V²)(V- nb) = nRT

For the Cl₂ van der Waals equation constant , a = 6.343 atm L²/mol² , b = 0.05422 L/mol

(P +(1.205)²*6.343 atm L²/mol² / (4.990)²) (4.990-1.205 mole0.05422 L/mol) = 1.205 mol*0.0821 atm.L/mol.K * 286.5 K

(P+0.370) *(4.92) = 28.34

4.92 P + 1.82 =28.34

4.92 P = 28.34-1.82

           = 26.52

P = 5.38 atm

B) Now using the Ideal gas law –

PV = nRT

P = nRT/V

    = 1.205 moles * 0.0821 atm.L.mol^-1.K^-1*286.5 K / 4.990 L

     = 5.68 atm.