Bond Enthalpy

[Arlene Paramo 1I]

When to do you make the standard reaction enthalpy negative? Is it when you're breaking or forming a bond and why does it need to be negative?

[Matthew Gutierrez 2D]

You make the bond enthalpy negative when you are forming a bond. It is negative because forming a bond is exothermic because the molecule becomes more stable and releases energy.

[Gabriel Esmailian 1F]

In order to break a bond, energy is needed. This uptake in energy constitutes a positive enthalpy value. On the other hand, to make bonds energy is release, and thus enthalpy value will be negative because energy is leaving the system.