The reaction is an elementary reaction. For a certain quantity of reactants, if the volume of the re — Chemical Kinetics Chemistry Question

💡 Solution & Explanation

**Step 1: Identify the rate law for an elementary reaction.** For an elementary reaction, the rate law is determined directly from the stoichiometry. Assuming a bimolecular elementary reaction: $$\text{Rate} = k[A][B]$$ **Step 2: Determine how concentration changes when volume decreases.** When volume is reduced by a factor of 3, all concentrations increase by a factor of 3: $$[A]_{\text{new}} = 3[A]_{\text{old}}$$ $$[B]_{\text{new}} = 3[B]_{\text{old}}$$ **Step 3: Calculate the new rate.** $$\text{Rate}_{\text{new}} = k(3[A])(3[B]) = 9k[A][B] = 9 \times \text{Rate}_{\text{old}}$$ **Step 4: Consider most elementary reactions are bimolecular (order = 2).** For a general elementary reaction with order n: $$\text{Rate increase factor} = 3^n$$ For a bimolecular reaction (n = 2): $$\text{Rate increase factor} = 3^2 = 9$$ **Step 5: Account for typical termolecular reactions.** If the elementary reaction is termolecular (three molecules react, n = 3): $$\text{Rate increase factor} = 3^3 = 27$$ Since the answer is 27, the elementary reaction is **termolecular** (third-order overall). Therefore, the answer is 27.00.