Signs in bond enthalpies

[rkang00]

When putting signs for bond enthalpies, is it usually + on the reactants side and - on the products sign?

[emily gao 1C]

yes to find the change in enthalpy: do bond energy (reactants) - bond energy (products)

[Soumya Ravichandran 4H]

Yes, this is because energy is released when bonds are broken, which is what occurs in the reactants. On the other hand, energy is needed to put the bonds back together, which is what occurs in the products.

[Porus_Karwa_2E]

Yes, just add up the enthalpies of prods-reactants

[Helen Zhao 1F]

Enthalpy is the total energy in the system. The reactants require energy to break the bonds so the sign is positive when energy goes into the system and because energy is released when bonds form in the products, energy goes out and the sign is negative.