Bond Enthalpies

[Susanna Givan 2B]

Can bond enthalpies ever be negative? If they can't be negative, why not?

[LovepreetSran_3H]

Bond enthalpies can never be negative because they are the energies required to break bonds.

[Neal_Agarwal_3B]

To add onto this topic, we can see that bond enthalpies are always positive in this equation for delta H, deltaH = bonds broken - bond formed. This shows that there is energy needed to break bonds and then energy released to form bonds. Since bond enthalpies are always positive it makes sense why we must subtract this positive value for the total number of bonds formed as that is the energy being released in the reaction. I hope this provides some additional clarification.

[Valerie Doan 3I]

Bond enthalpies are positive because breaking a bond is an endothermic process versus forming bonds is exothermic. For bond enthalpies, we are looking at the energy required to break a bond. But, for the equation delta H= bonds broken - bonds formed, we have to change the values of bond formation to negative (which is already accounted for in this equation).

[Noa Popko 3I]

To break bonds we require energy. Thus it is an endothermic process meaning the enthalpy is always positive.

[Mandy Mg 2J]

Bond enthalpies can not be negative because they are the energy that is required to break bonds, which is an endothermic process. However, if you try to calculate change in enthalpy with bond enthalpies (deltaH = bonds broken - bonds formed) and it just so happens that the energy required to form the bonds in the reaction is greater that the energy of the bonds broken, the change in enthalpy will be negative, but never the bond enthalpies themself.

[Sevde Coban 2J]

The bond enthalpy measures the strength of a chemical bond based on the energy required to break the bond. Because energy is required, the process is endothermic, so the energy cannot be negative.

[kareena_prasad]

They cannot be negative because the reaction they represent is endothermic.

[Sevde Coban 2J]

Bond enthalpies are always positive because in order to break a bond, heat must be supplied, which means that breaking a bond is always endothermic. The heat supplied is always positive.

[Zoe Dhalla 3I]

Generally, a positive change in enthalpy is required to break a bond, while a negative change in enthalpy is accompanied by the formation of a bond. In other words, breaking a bond is an endothermic process, while the formation of bonds is exothermic.

[Acharya Ranawat 3E]

It always requires energy to break a bond. So they have to always be positive since it takes energy to break a bond.

[Maham Kazmi 2J]

Bond enthalpies are defined as the energy needed to break a bond. This value would always be positive since energy is always required to break a bond.

[Jonathan Alterman 1C]

Since breaking a bond requires an input of energy, the bond enthalpy would always be a positive value, indicating this input with a positive sign.

[Ivan Huang Dis 3B]

you must add energy to break a bond so it must be positive

[Isha Tripathi 2F]

Bond enthalpies must be positive since energy must be added

[Isha Tripathi 2F]

Bond enthalpies must be positive since energy must be added