Question

Pure carbon dioxide (PCO2 = 1 atm) decomposes at high temperature. For the reaction system 2 〖CO〗_2 (g) ⇌2 CO(g)+ O_2 (g) Is this reaction endothermic? Calculate the value of Kp at each temperature.

Answer 1

Answer:

The reaction decomposes more as T increases, therefore it is ENDOTHERMIC, meaning it requires energy to form CO and O₂.

Kp for each specie...

Kp = CO^2 O2 / (CO2)^2

for

T = 1500

Assume 1 atm for CO2, after % dissociation

P-CO2 left = 1*(1-0.048/100)= 0.99952

P-CO formed = 1-0.99952 = 0.00048

P-O2 = (1-0.99952)/2 = 0.00024

so..

Kp = CO^2 O2 / (CO2)^2

Kp = (0.00048^2)(0.00024) / (0.99952^2) = 5.53*10^-11

T = 2500

Assume 1 atm for CO2, after % dissociation

P-CO2 left = 1*(1-17.6/100)= 0.824

P-CO formed = 1-0.824= 0.176

P-O2 = (1-0.176)/2 = 0.088

so..

Kp = CO^2 O2 / (CO2)^2

Kp = (0.176^2)(0.088) / (0.824^2) =0.0040

T = 3000

Assume 1 atm for CO2, after % dissociation

P-CO2 left = 1*(1-54.8/100)= 0.452

P-CO formed = 1-0.452= 0.548

P-O2 = (1-0.452)/2 = 0.274

so..

Kp = CO^2 O2 / (CO2)^2

Kp = (0.548^2)(0.274) / (0.452^2) =0.4027

Explanation: