Solutions to Web Experiment: Chemical Equilibrium

Web Experiment: Chemical Equilibirum
Answers to Questions






  1. Initially two A molecules, represented by red balls, collide and form a B molecule represented by a blue ball. After a few seconds some of the B molecules that were formed dissociate into A molecules. Over the course of the animation a few but not all collisions between two A molecules continue to result in the formation of B molecules. At the same time some but not all of the B molecules continue to dissociate into A molecules. After the first fifteen seconds , the number of A molecules and the number of B molecules appear to remain nearly constant.


  2. Initially, there are 80 A molecules (red balls) and zero B molecules (blue balls) in the container. The number of A molecules rapidly decreases and number of B molecules increases. After about 30 seconds the number of A molecules and the number of B molecules oscillate around the mean values of 28 and 25.



  3. Initially, there are 40 B molecules (blue balls) and zero A molecules (red balls) in the container. The number of B molecules decreases and number of A molecules rapidly increases. Like exercise #2 the number of A molecules and the number of B molecules oscillate around the mean values of 28 and 25 after about 30 second. The value for the average Kc (0.33) is similar the value (0.31) found in exercise #2.



  4. Both equilibria have the same mean number of A molecules and the same mean number of B molecules. The two values for the average Kc are similar. The equilibrium states in exercises #2 and #3 are effectively the same state.


  5. At 380 K the mean number of A molecules (50) at equilibrium is larger than at 298 K and the mean number of B molecules (14) is smaller. The value of average Kc is a smaller number (0.054) at 380 K than at 298 K. An increase in the temperature causes the equilibrium to shift to the left.