Question

The equilibrium constant at 243 "C for the equation PC (g) + Cl,(g) PCl (g) is K, 4.50 x 103 bar. Calculate the value of AGn at 243 'C. р гхn AGExn kJ/mol TXn In which direction is the reaction spontaneous when PCl, Cl,, and PCl are at standard conditions? left right With the temperature at 243 'C and the partial pressures of the gases of PpCi, = 0.403 bar, PC, = 4.88 x 10-6 bar, calculate the value of AGxn = 0.935 bar, and Рсь, AGxn kJ/mol In which direction is the reaction spontaneous under these conditions? right Oleft

Answer 1

PC lz (9) - PC lz (g) + Cl₂ (9) 7 R = Universal gas AGRxn = - RT lnkp1 constant T= Absolute tempenature = -8.314 J. moekt 1 = (273 +243) K 516k x ln (4.50x103 = 516k =-36086.96 I mot = -36.09 KJ molt [ 1 KJ = 10 3 7 * As the value of Groxn is negative, the reaction is spontaneous in night direction when Pelz , cle and Palg are at Standard Conditions. roxh AG Gout RT ln PP odzi Pela Preces = -36.09 KI mol +8.314x10² KI mol'kli 516 K x li 0.4.03 * 0.935 4.88 x 10-6 = - 36.09 KI mol + 48.28 KI molt = 12.19 KI molt * Value of AG man is positive. Therefore the reaction is spontaneous in left direction