How to find out Bond energy?

Exams usually provide us with two things. The structure and the energy value. With that you can have compound and the energy needed to create/break them. An example would be Hydrogen + Chlorine. H--H + Cl--Cl = H-Cl. H--H=436 kj/mol, Cl--Cl=242 kj/mol H--Cl=431kj/mol On the left hand side, we are breaking the bonds. The answer would be positive as because it requires energy. [678kJ] The right hand side is making bonds so it would be negative as it releases energy. [-862kJ] [678-862=-184kJ] This reaction is Exothermic, as energy is being released [its negative]