Answer:
Step-by-step explanation:
You will need to look up the Standard Heats of Formation* for each substance and apply Hess's Law Equation.
ΔH⁰(rxn) = ∑ΔH⁰(Products) - ∑ΔH⁰(Reactants)
*Std Heats of Formation can be found in the appendix of most college chem texts.
For this problem:
Given CaCO₃(s) => CaO(s) + CO₂(g)
∑ΔH⁰: -635.1 Kj/mole -393.5Kj/mole -1206.9
ΔH⁰(rxn) = [(-393.5 Kj/mole) + (-393.5Kj/mole)] - (-1206.9Kj/mole)
= (-635.1 -393.5 + 1206.9) Kj/mole
= +178.3 Kj/mole