posted by a Canadian on .
Firstly, is this right?:
Exothermic reactions have a negative enthalpy change value because the enthalpy of the reactants are greater than the enthalpy of the products *since the reactants have weaker bonds.*
(especially the starred part, I'm wondering about)
If so, how come weaker bonds means higher energy/enthalpy?
My personal take on this is that you are "worrying this point to death". I look at it this way.
When (n*dH products) - (n*dH reactants) = - number, we have an exothermic reaction and it gives off heat. When the number is + it is an endothermic reaction and it absorbs heat. I don't know that it says anything about which bonds are stronger and/or which are weaker.