Explore a particulate level model of the reaction between hydrogen atoms and oxygen atoms. I think an important point that is demonstrated in this simulation found at Concord.org is that when a bond is formed in a collision, energy is released. The amount of energy released increases the vibrational modes in the molecule formed. This energy could break the bond (the bond vibrates and will eventually break) unless the molecule collides with another particule and the energy is transferred. Watch the simulation and see how this happens.