The change in enthalpy is the change in heat energy of a reaction and is calculated by (Hint: Hess' Law): Group of answer choices
a. Sum of reactant enthalpies plus the sum of product enthalpies
b. Sum of reactant enthalpies minus the sum of product enthalpies
c. Sum of product enthalpies times the sum of reactant enthalpies
d. Sum of product enthalpies minus the sum of reactant enthalpies