Login to the computer and open a web browser. Go to https://phet.colorado.edu/en/simulation/legacy/reactions-and-rates. Open or download the simulation.
When the simulation is open, click on the “Many Collisions” tab.
Look at the screen and observe everything you can find out about the reaction pictured, A + BC ( AB + C.
Click “Show stopwatch”.
Turn on the bar chart.
Let each experiment run for 600 seconds to allow enough time for equilibrium to be established.
1) Predict what will happen when 50 A’s are added to the box and 50 BC’s are added.
2) In the box labeled “current amounts,” enter 50 for A and 50 for BC.
a) Was your prediction correct? Describe and explain any differences.
b) Describe the nature of dynamic equilibrium when small numbers of particles (such as 50, as compared to 6.022 x 1023) are present.
3) Predict what will happen when the temperature is raised so it is NOT above the activation energy max but IS above the energy level of the products.
4) Raise the temperature as described. Did your prediction come true? Describe and explain any differences.
5) Predict what will happen when the temperature is raised so it is above the activation energy max.
6) Raise the temperature as described. Again, was your prediction correct? Describe and explain any differences.
7) What did you notice about the rate at which reactants/products fluctuated between the three different temperatures? If you didn’t notice anything, hit “reset all” and test it again.
8) Did temperature affect equilibrium position? Did it affect it in the way you expected? Explain.
9) Did temperature affect reaction rate? Did it affect it in the way you expected? Explain.
Le Châtelier’s Principle
Instructions: Now choose the “Rate Experiments” tab. As you play with the sim, answer the questions below.
11) In the previous lab (“Exploring Equilibrium”) you investigated the effect of temperature on equilibrium position; you may have found that temperature did not affect equilibrium in quite the way you expected. Add 80 A’s and 80 BC’s to the box for the first reaction and begin the experiment; let the reactions run until equilibrium is reached. Knowing Le Châtelier’s Prinicple, now predict and explain what will happen to the equilibrium position when the temperature is raised and lowered. Then test your ideas using the sim and explain your observations. Give numerical data to support your claims.