The equation gives one route by which ozone is formed in the upper atmosphere: $\text{O}_2 + \text{O} \rightarrow \text{O}_3\quad \Delta H = -392\,\text{kJ mol}^{-1}$. Explain, in terms of bond breaking and bond forming, why this reaction is exothermic.
When 1 mole of oxygen molecules reacts, 392 kJ of energy is given out. Calculate the amount of energy released when 48.0 g of oxygen molecules react.
Name a pollutant that destroys ozone in the upper atmosphere.
Ozone molecules decompose into oxygen molecules in a reversible reaction: $2\text{O}_3(\text{g}) \rightleftharpoons 3\text{O}_2(\text{g})\quad \Delta H = +143\,\text{kJ mol}^{-1}$. The reaction is studied at a temperature of $400^\circ\text{C}$. Describe and explain what happens to the position of equilibrium if the pressure is increased.
The reaction is studied at 25 atmospheres pressure. Describe and explain what happens to the position of equilibrium if the temperature is decreased.
Describe and explain what will happen to the rate of the reaction if the temperature is decreased.