The decomposition of hydrogen peroxide in aqueous solution is catalyzed by solid MnO₂ according to
2 H₂O₂(aq) → 2 H₂O(l) + O₂(g)
Three experiments were carried out at the same temperature using equal masses of MnO₂ that differed only in total exposed surface area. The volume of O₂(g) produced during the first 20 s was measured.
Experiment | MnO₂ Surface Area (cm²) | O₂ Volume in First 20 s (mL)
1 | 120 | 15.0
2 | 600 | 73.0
3 | 1 000 | — (to be predicted)
Answer the following:
(1) Part 1: (a) Calculate the initial rate of O₂ production in mL s−1 for Experiments 1 and 2.
(2) Part 2: (b) Using proportional reasoning based on your results from part (a), predict the volume of O₂(g) that would be produced in the first 20 s of Experiment 3. State any assumption you make.
(3) Part 3: (c) Give one possible reason why the actual measured volume in Experiment 3 might deviate from the value you predicted in part (b). Explain your reasoning in terms of factors that influence reaction rate other than surface area.