Last modified: Wed 12/31/1969 06:00:00 pm
BCE

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Answer all of the questions below. If you do not know an answer enter CNA. However, it will help me the most if you answer each question with your best intuition/idea about what would be a reasonable answer.

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As we expand our application of aqueous acid-base chemistry we will look at the next type of acid-base aqueous equilibrium system which is called common ion.

1. A solution in a container is 0.500 M HC2H3O2 and 0.400 M NaC2H3O2. Answer the following questions about this solution.

a) What is the initial concentration of HC2H3O2 in the solution?

[HC2H3O2] = M

b) What is the initial concentration of C2H3O2 -(from the NaC2H3O2) in the solution?

[C2H3O2-] = M

c) Complete the ICE table below

Reaction

HC2H3O2

H+

+ C2H3O2-

Initial

M

 

M

M

Change

M

 

M

M

Equilibrium

M

 

M

M

 

2. The Ka for HC2H3O2 is 1.7 x 10-5. Calculate the pH of the common ion solution above using the information from your ICE table.

pH =

After completing the calculation use the Buffer Simulation to measure the pH of a solution that is 0.500 M HC2H3O2 and 0.400 M NaC2H3O2.

3. The pH of a solution that only contains acetic acid (0.500 M HC2H3O2) is 2.54. Look at the pH you calculated in Q2 above. How do you explain the difference in pH of these solution?

4. Is there anything about the questions that you feel you do not understand? List your concerns/questions.

5. If there is one question you would like to have answered in lecture, what would that question be?