Question

Use the link above to 'run' the experiment. Go through each test in the suggested order and select the options from the list that best fit your observations. Each box should have two solutions when you complete this portion.

To run a test click "Run Reaction". Use the drop down on the simulation to select a new variable and the choose to decrease. Next click "start over" to reset and choose the next condition. The sequence below matches your data table.

Control

Decrease Temperature

Increase Temperature

Decrease Concentration

Increase Concentration

Decrease Surface Area

Increase Surface Area

Add Catalyst



(8 points)
Response input area 1 out of 8.Currently contains All A + B react to form C..
Response input area 2 out of 8.Currently contains Some reactants remain, only some product is formed..
Response input area 3 out of 8.Currently contains All A + B react to form C..
Response input area 4 out of 8.Currently contains Particles collide slower. (Lower slope).
Response input area 5 out of 8.Currently contains Particles collide faster. (Steeper slope).
Response input area 6 out of 8.Currently contains Some reactants remain, only some product is formed..
Response input area 7 out of 8.Currently contains All A + B react to form C..
Response input area 8 out of 8.Currently contains Particles collide faster. (Steeper slope).
Question 3
Please select any two variables (temperature, surface area, concentration and addition of a catalyst) to compare to the control experiment. You may describe the graph each produces and/or the number and behavior of particles of A, B, and C at the beginning and end of your test. For each of your choices, explain 'why' you think the rate of reaction changed with your adjustments. You may write your answer in paragraph or list form just be sure to tell me which two variable you select.

6 points

(6 points)

Answer 1

I choose: Increase Temperature and Add Catalyst.

1) Increase Temperature
- Graph/particle behavior: The reaction graph shows a steeper initial slope than the control (faster decrease of A & B, faster increase of C). Particles move faster and collide more often; more A and B are converted to C in a shorter time. The final amounts (extent of reaction) are the same as the control, but the time to reach that final amount is shorter.
- Why the rate changed: Raising temperature increases the kinetic energy of the particles, so collision frequency goes up and a larger fraction of collisions have energy ≥ activation energy. That increases the number of successful collisions per unit time, so the reaction rate increases.

2) Add Catalyst
- Graph/particle behavior: The graph also shows a steeper slope vs. the control (faster formation of C), so A and B are consumed faster and C appears sooner. Particle speeds are similar to the control, but more collisions become productive because the catalyst provides an easier pathway. The final concentrations are unchanged compared to the control (same total conversion), only reached more quickly.
- Why the rate changed: A catalyst provides an alternate reaction pathway with a lower activation energy. This raises the fraction of collisions that are effective without changing particle kinetic energies, so the reaction rate increases while the overall equilibrium/extent is unaffected.