Is the synthesis of ozone, #O-3#, from oxygen, #O_2#, an example of an exothermic or endothermic reaction?

1 Answer
Aug 23, 2017

Answer:

#3/2O_2+DeltararrO_3#

Explanation:

The reaction as written is ENDOTHERMIC, and it is accomplished in the upper atmosphere by the impact of photons on the dioxygen molecule, i.e.

#O=O+hnurarr2dotO#

#dotO+O_2rarrO=stackrel(+)O-stackrel(-)O#

The first reaction is bond-breaking, and is certainly endothermic, and the second reaction, bond-making, is exothermic. The balance is towards bond-breaking, i.e. the reaction as written in the intro is endothermic.