Enthalpy

[Marsenne Cabral 1A]

Why is the enthalpy of bonds (delta H b) always greater than zero and endothermic?

[Nada AbouHaiba 1I]

They're just given as positive values, but if you're forming the bond then you would write them as negative because it is an exothermic process

[Toru Fiberesima 1L]

Bond breaking is an endothermic process ie a process that requires energy. For endothermic reactions, the products of the reaction have a greater enthalpy than the reactants, and heat is absorbed by the system from its surroundings. Therefore, the delta H b must be positive because the energy is being added to the system.

[Bruce Chen 2H]

Endothermic is using heat, so delta H would be positive, whereas exothermic reactions lose heat so it'll be a negative delta H.

[Lopez_Melissa-Dis4E]

Endothermic requires heat, therefore delta H is positive.
Exothermic releases heat, therefore delta H is negative.
Whether you are forming bonds (endothermic), or breaking bonds (exothermic) you would refer to your positive/negative value of delta H.

[Xinyi Zeng 4C]

Just to add on, "enthalpy of bond" has a more formal name as "Bond Energy" and its definition is the amount of energy required to break that particular bond. Breaking of bond requires energy and hence is endothermic.

[Charles Gu 1D]

In order to break bonds, you need a input of heat so thats why delta h is positive (endothermic)