If C(s) + O2 (g) → CO2 (g);∆H = X, and CO (g) + 1/2 O2 (g) →CO2 (g); ∆H = Y,Then the heat of formation of CO(g) is

Explanation

To find the heat of formation ΔH∘f of CO(g),we can use Hess's law,which states that the total enthalpy change for a reaction is same,regardless of the number of steps taken to get from the reactants to the products.In this case, we can use the given reactions to calculate ΔH∘f for CO(g). First, let's reverse the second equation and change its sign because we need to find the formation of CO(g) CO2(g)→CO(g)+1/2 O2(g); ΔH=−Y Now, let's add this equation to the given equation: C(s)+O2(g)→CO2(g); ΔH=X + CO2(g)→CO(g)+1/2O2(g); ΔH=−Y When we add these equations, the intermediate CO2(g) and 1/2O2(g) cancel out, leaving us with: C(s)→CO(g); ΔH=X−Y Therefore, the heat of formation CO(g) is X−Y.