Question

Question #50c2f

Answer 1

The standard heat of reaction is -178.3 kJ.

We have the following information:

For most chemistry problems involving `ΔH_f^"o"`, you need the following equation:

`ΔH_(rxn)^"o" = ΣΔH_f^"o"("p") - ΣΔH_f^"o"("r")`,

where `"p"` = products and `"r"` = reactants.

`ΣΔH_f^"o"("p") = 1 cancel("mol CaCO₃") × "-1206.9 kJ"/(1 cancel("mol CaCO₃")) = "-1206.9 kJ"`

`ΣΔH_f^"o"("r") = 1 cancel("mol CaO") × "-635.09 kJ"/(1cancel("mol CaO")) + "1 mol" cancel("CO₂") × "-393.509 kJ"/(1cancel("mol CO₂")) = "-1028.599 kJ"`

`ΔH_("rxn")^"o" = ΣΔH_f^"o"("p") - ΣΔH_f^"o"("r") = "-1206.9 kJ + 1028.599 kJ" = "-178.3 kJ"`