Question

Use the PhET Reactions & Rates interactive simulation to simulate a system. On the "Single collision" tab of the simulation applet, enable the "Energy view" by clicking the "+" icon. Select the first A+BC⟶AB+C reaction (A is yellow, B is purple, and C is navy blue). Using the "straight shot" default option, try launching the A atom with varying amounts of energy. What changes when the Total Energy line at launch is below the transition state of the Potential Energy line? Why? What happens when it is above the transition state? Why?

a) The reaction rate increases; more collisions occur.
b) The reaction rate decreases; fewer collisions occur.
c) The reaction proceeds to completion; no collisions occur.
d) The reaction reaches equilibrium; collisions are balanced.

Answer 1

When the Total Energy line is below the transition state, the reaction rate decreases. When it is above the transition state, the reaction rate increases.

Step-by-step explanation:

When the Total Energy line at launch is below the transition state of the Potential Energy line, the reaction rate decreases and fewer collisions occur. This is because the reactant molecules do not have enough energy to overcome the activation energy barrier and form the activated complex. Therefore, the reaction proceeds at a slower pace.

On the other hand, when the Total Energy line at launch is above the transition state of the Potential Energy line, the reaction rate increases and more collisions occur. The reactant molecules have sufficient energy to overcome the activation energy barrier and form the activated complex, leading to a faster reaction.