Answer to Question #104004 in Physical Chemistry for Bharti

Question

Calculate Vr, Hr, and Sr for the following using appropriate generalized correlation:
Pure CO2 at 400k and 200 bar.
A mixture of 40% ethane and 60% ethylene.

Answer 1

For pure CO₂ 400K 200 bar

T_pc = 304.2 K

p_pc = 73.83 bar

T_pr = 400/304.2 = 1.31

p_pr = 200/73.83 = 2.71

At these T_pr and p_pr :

Z⁰ = 0.659

Z¹ = 0.207

(Hr/(RT_pc))⁰ = -2.03

(Hr/(RT_pc))¹ = -0.243

(Sr/(R))⁰ = -1.15

(Sr/(R))¹ = -0.413

ω=0.224

Z = Z⁰ +ω *Z¹ = 0.705

Vr = RT/P*(Z-1) = 8.314* 400/(200*10^5) * ( 0.705-1) = -49.1 cm3/mol

(Hr/(RT_pc)) = (Hr/(RT_pc))⁰ + ω *(Hr/(RT_pc))¹ = -2.08

Hr = -2.08 * 8.314 * 304.2 = -5261 J/mol

(Sr/(R)) = (Sr/(R))⁰ + ω *(SR/(R))¹ = -1.24

Sr = -1.24 * 8.314 = -10.3 J/(mol*K)

all reference data was taken from

INTRODUCTION TO CHEMICAL ENGINEERING THERMODYNAMICS

J. M. Smith