A chemical bond is an electrical attraction between atoms or ions
To break the bond completely, the atoms or ions need to theoretically be an infinite distance apart
The quantity of energy required to break a particular bond in a molecule is the bond enthalpy
The stronger the bond, the more energy required to break it, so higher bond enthalpy
Bond-breaking is always endothermic
Bond-making is always exothermic
Shorter bonds are stronger
Bonds have a balance of repulsive of attractive and repulsive forces
Double or triple bonds are stronger as there are more electrons attracted to nuclei
Bond enthalpies are typically an average
Depends on the individual compound
Many reactions need heating to start
Initial energy required to stretch and break bonds
Subsequent exothermic bond-making sustains reaction
\[\textup{enthalpy change}=\sum \textup{bonds broken} - \sum \textup{bonds formed}\]