Chemistry - Will heating diatomic oxygen enough break the O=O bonds?

Solution 1:

Yes, adding at least 495 kJ/mol of kinetic energy one way or another (thermally, photochemically by irradiation with photons of that energy, sonication, etc.) will cause $\ce{O2}$ to dissociate into monatomic oxygen.

$$\ce{O2 ->C[energy]\ 2O}$$

Solution 2:

Yes. For quantitative information see Gas Phase Reaction Kinetics of Neutral Oxygen Species, particularly section 2.1, especially table 4, which gives the equillibrium constant $K_D$ as a function of temperature.


$K_D = \frac{[O]^2}{[O_2]}$

$K_D$ exceeds 1 above ~1000K, in units of particles per cubic centimeter.

Solution 3:

It is important to point out that heat is a bulk (statistical mechanical) concept while bond strength is largely quantum mechanical. If I am not mistaken, heat/temperature can be defined using pictures like molecules striking the edges of a container, or perhaps from energy/entropy relationships that involve Avagadro's number of molecules.

To your question, this means that given a large enough thermal energy, other molecules of $\ce{O2}$ will likely collide with an $\ce{O_2}$ molecule in question -- thereby bringing their nuclear kinetic energy to bear, and perhaps causing a dissociation.

I don't think that an isolated molecule of $\ce{O_2}$ (or anything for that matter) will spontaneously rupture because of heat, because here heat is not a well-defined quantum mechanical concept, as it is mediated by many moving atoms.

Solution 4:

Yes. Adding enough thermal energy to anything will disrupt the bonds.