Experiment 01
Select a factor
Change one factor at a time, keeping the others constant.
Chapter 11 · On-screen experiments, rate comparisons, Maxwell–Boltzmann distribution, catalytic mechanisms and knowledge checks.
Change one factor at a time, keeping the others constant.
What do you predict?
Schematic visualization of motion and collisions, not an atomistic simulation.
The curve follows a hypothetical kinetic model for visual comparison, not a universal rate law. 100% denotes conversion of the particular initial amount; it does not imply that the same moles of products are always formed.
Compare the fraction of molecules with kinetic energy at least Eₐ.
As temperature increases, the distribution spreads toward higher kinetic energies. A larger fraction of molecules can exceed the energy threshold.
This is an ideal gas translational kinetic-energy distribution with energy per mole as the variable. The shaded area equals the calculated fraction. Real reaction mechanisms require additional data.
Keep the reactants, products and ΔH unchanged. Compare the energy pathways.
The energy values are an illustrative hypothetical example, not measured values for the specific reactions described.
Schematic comparison: the reaction starts more slowly without initially added Mn²⁺; adding this catalytic product at the start accelerates it earlier.
Explore why an enzyme is most active within a particular range of conditions.
The substrate binds to the appropriate region of the enzyme. A change in its three-dimensional structure may reduce or eliminate catalytic activity.
Choose one answer for each question. Explanations are provided at the end.
Ask what will happen before changing a factor in the laboratory.
2. Observation (5 min)Compare concentration and pressure; explain when pressure actually affects the reaction.
3. Interpretation (5 min)Use Maxwell–Boltzmann to distinguish more frequent collisions from a larger fraction of effective collisions.
4. Catalysis (5 min)Emphasize that Eₐ decreases through an alternative pathway but ΔH remains unchanged.
5. Feedback (3 min)Use the mini quiz as a quick oral knowledge check.
Pressure does not affect reactions without gaseous reactants in the same way. Increasing a solid’s surface area does not necessarily change its total available amount. A catalyst does not change ΔH and is not consumed overall. Increasing temperature does not always increase enzyme activity.