Question

A gas phase that is at equilibrium with respect to the following reaction at 500 K contains carbon dioxide, carbon monoxide, and oxygen.

2CO_2(g) → 2CO_(g) + O_2(g)

a) Calculate the equilibrium partial pressure of oxygen if the carbon dioxide partial pressure is 0.20 atm and the carbon monoxide partial pressure is 0.40 atm. The ∆G°_f values for CO₂ and CO at 500 K are -94.389 kcal/mol and -37.140 kcal/mol, respectively.

b) Calculate the total pressure at equilibrium if the mixture contains 3.50 moles of carbon dioxide, 2.00 moles of carbon monoxide, and 2.10 moles of oxygen

Answer 1

Solution:

Step 1: (a)

Here, we have to calculate the equilibrium partial pressure of oxygen.

Given equation

The equilibrium pressure for the equation is given below

Given that

  

We know that,

Again we know

= 3.63 x 10³

Step 2:

Initially, Partial pressure of CO₂ = 0.2 atm

Initially, Partial pressure of CO = 0.4 atm

At equilibrium, Partial pressure of CO₂ = (0.2 -2x) atm

Partial pressure of CO = (0.4+2x) atm

Partial pressure of O2 = x atm

K_p = (0.2-2x)²/ x (0.4+2x)

   3.63 x 10³ = 0.2/0.4x

The equilibrium pressure for oxygen is

Step 3: