2.4.3Lab: Disturbing Equilibrium Pre-lab Chemistry Sem 2 Points Possible:50.

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Answer these questions before beginning the lab. Be sure to turn them in when you submit your lab report. 1. What does stressing an equilibrium system mean? How is stress applied? The reversible rea... ction for the pH indicator bromophenol blue is (C19H8Br4O5S)H– ↔ (C19H8Br4O5S)2– + H+. Write the equilibrium expression for this reaction. 3. What direction do you predict the addition of an acid to the solution containing bromophenol blue will drive the equilibrium? Explain your prediction in terms of Le Châtelier's principle. Hint: Think about what the addition of an acid does to the concentration of H+ ions 4. What direction do you predict the addition of a base to the solution containing bromophenol blue will drive the equilibrium? Explain your prediction in terms of Le Châtelier's principle. 1. What is the color of bromophenol blue in an acid? In a base?2. How did you get the solution to change from blue to yellow? 4. How did you get the solution to change from yellow to blue? 5. Why did the solution change from yellow to blue (what chemical reaction happened)? 6. After Procedure Step 3, the solution in Well A1 was in equilibrium. What happened to the solution in Well A1 during Procedure Step 5? Did the equilibrium shift? Explain this on the basis of the Le Chatelier Principle? 7. Why did the colors in the Wells A1 and A3 change a second time in Procedure Steps 7 and 8? Was this because of reversible reactions? [Show More]

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