A-LevelChemistryReaction kinetics9701/12 · May/June 2019 · Q11 Mark
The Boltzmann distribution of molecular energies in a sample of aqueous hydrogen peroxide at room temperature is shown. [Figure 1.1] Which diagram shows the Boltzmann distribution of molecular energies of aqueous hydrogen peroxide maintained at room temperature when a catalyst, manganese(IV) oxide, is added?
This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.
ABoltzmann distribution curve with peak at the original energy and original height, but with the activation energy line shifted to a lower energy, resulting in a larger shaded area of molecules with sufficient energy.
BBoltzmann distribution curve with peak shifted to a lower energy and a higher peak height, and with the activation energy line shifted to a lower energy than in the original diagram, resulting in a larger shaded area of molecules with sufficient energy.
CBoltzmann distribution curve with peak shifted to a higher energy and a lower peak height, and with the activation energy line shifted to a higher energy than in the original diagram, resulting in a larger shaded area of molecules with sufficient energy.
DBoltzmann distribution curve with peak at the original energy and original height, and with the activation energy line at its original position, but with a larger shaded area of molecules with sufficient energy.
✓ Correct answer
B: Boltzmann distribution curve with peak shifted to a lower energy and a higher peak height, and with the activation energy line shifted to a lower energy than in the original diagram, resulting in a larger shaded area of molecules with sufficient energy.
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