Given the values of K shown below, determine the value of K for the reaction

Question

Given the values of K shown below, determine the value of K for the reaction,

Ca(s) + 1/2 O₂(g) + CO₂(g) <=> CaCO₃(s)

Ca(s) + 1/2 O₂(g) <=> CaO(s)         K = 9,438

 CaCO₃(s) <=> CaO(s) + CO₂(g)    K = 8,106

Give your answer to 3 or 4 decimal places

Answer 1

Target equation is Ca(s) + 1/2O₂(g) + CO₂(g) <==> CaCO₃(s)

Using Hess Law, we can obtain the following:

Ca(s) + 1/2 O₂(g) <==> CaO(s) K = 9438

CaO(s) + CO₂(g) <==> CaCO₃(s) K = 1/8106 = 1.233x10^-4

Adding these two, we obtain

Ca(s) + 1/2O₂(g) + CaO(s) + CO₂(g) <==> CaO(s) + CaCO₃(s) and K' = 9438 x 1.233x10^-4

This gives us the target equation with a K value of 1.164 (to 3 decimal places)