Calculate the value of Kp for the equation: C(s)+CO2(g)=2CO(g)

Question

_{Given that at a certain temperature}

_{C(s)+2H2O(l)=CO2(g)+2H2(g) Kp1=3.05}

_{H2(g)+CO2=H2O(l)+CO(g) Kp2=0.621}

_

Answer 1

Refer to Hess' Law

C(s) + CO₂(g) ==> 2CO(g) ... TARGET EQUATION

Given:

eq.1: C(s) + 2H₂O(l) ==> CO₂(g) + 2H₂(g) ... Kp = 3.05

eq.2: H₂(g) + CO₂(g) ==> H₂O(l) + CO(g) ... Kp = 0.621

Procedure:

copy eq.1 to get C(s) on the left: C(s) + 2H₂O(l) ==> CO₂(g) + 2H₂(g) ... Kp = 3.05

double eq.2 and copy it: 2H₂(g) + 2CO₂(g) ==> 2H₂O(l) + 2CO(g) ... Kp = (0.621)² = 0.386

add the 2 equations together and combine/cancel like terms:

C(s) + 2H₂O(l) + 2H₂(g) + 2CO₂(g) ==> CO₂(g) + 2H₂(g) + 2H₂O(l) + 2CO(g)

C(s) + CO₂(g) ==> 2CO(g) TARGET EQUATION

To obtain the new Kp for the overall target equation, we multiply the Kp's for each reaction:

Kp = (3.05)(0.386)

Kp = 1.18