Question

If the molar enthalpy for the formation of a compound is -192 kJ, why is the molar enthalpy of the decomposition of that compound 192 kJ?

A.) because of the Law of conservation of heat
B.) because of the law of conservation of energy
c.) because of the law of conservation of mass
d.) because of the law of conservation of enthalpy

Answer 1

formation means it's an exothermic reaction, hence it's a negative value (favorable reaction). A positive enthalpy is an endothermic reaction (non favorable reaction) . Or the answer D

Answer 2

B.) because of the law of conservation of energy
There is not " law of conservation of enthalpy" , it is Hess's Law or law of conservation of energy or First law of thermodynamics.
https://en.wikipedia.org/wiki/Hess's_law

Answer 3

Oh fudge, I'm forgetting my chemistry ;-;