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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1. Ka for HC2H3O2 is 1.8 x 10-5 and Kb for C2H3O2- is 5.6 x 10-10. Which species has the larger K?

2. Based on your response in Q1 if we have a solution that is 0.100 M HC2H3O2 and 0.100 M NaC2H3O2 will the solution be acidic or basic?

3. Calculate the pH of a 500 mL solution that is 0.100 M HC2H3O2 and 0.100 M NaC2H3O2.

pH =

4. The solution in Q3 is called a buffer solution. The important charateristic of a buffer solution is ability to resist large changes in pH when small amounts of strong acid or strong base are added. Consider the pH calculated in Q3, if a small amount of HCl is added to the solution will the pH increase or decrease? Provide a short response explaining your answer.

5. In a solution that is 0.100 M HC2H3O2 and 0.100 M NaC2H3O2 what is the formula of the weak acid and the formula of the weak base in the solution.

Formula of the weak acid component of the buffer

Formula of the weak base component of the buffer

6. If some HCl is added to the buffer solution in Q5 write a chemical equation that describes how the buffer solution neutralizes the added HCl.

7. If some NaOH is added to the buffer solution in Q5 write a chemical equation that describes how the buffer solution neutralizes the added NaOH.

8. Calculate the pH of the buffer in Q5 after adding 0.0200 mol of NaOH to the buffer solution.

pH =

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

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