In atmospheric chemistry, one proposed step in the formation of nitrate radicals is the following elementary reaction, which occurs in the gas phase at moderate altitudes:
NO₂(g) + O₃(g) → NO₃(g) + O₂(g)
Answer the following questions about this elementary process.
(a) Describe what is meant by the term “elementary reaction” in the context of chemical kinetics.
(b) Identify the molecularity of the reaction shown above and explain your reasoning.
(c) Explain how the stoichiometry of this elementary reaction determines the form of its rate law without requiring experimental rate data.
(d) Discuss why the procedure used in part (c) is generally not applicable to overall balanced reactions whose mechanisms are unknown.