1. Lecture 183/2/07

2. QUIZ 1. True or False: Buffer solutions are always at pH 7. 2. For each pair, which will have a lower pH? 1. 0.1 M HFor0.1 M NaF 2. 0.1 M HNO 3 or 0.1 M HNO 2 3. 0.1 M HNO 3 or 0.1 M HF 4. 0.1 M NH 3 or 0.1 M NaF 5. 0.1 M H 2 Sor 0.1 M H 2 Se

4. Equivalence point (NaOH titrating HF) X-axis Y-axis

5. Building a titration curve via calculations Comparison of a titration of a strong acid vs. a weak acid Region x-axis (mL of acid/base) 0.1 M NaOH y-axis (pH) 100 mL of 0.1 M HCl y-axis (pH) 100 mL of 0.1 M HF Initial pH 012.10 Before the equivalence point (1/2 equiv. point) 501.47 equivalence point 10077.93 After the equivalence point 15012.3

7. ½ Equivalence point (NaOH titrating HF) X-axis Y-axis

8. Building a titration curve via calculations Comparison of a titration of a strong acid vs. a weak acid Region x-axis (mL of acid/base) 0.1 M NaOH y-axis (pH) 100 mL of 0.1 M HCl y-axis (pH) 100 mL of 0.1 M HF Initial pH 012.10 Before the equivalence point (1/2 equiv. point) 501.473.16 equivalence point 10077.93 After the equivalence point 15012.3

10. After Equivalence point (NaOH titrating HF) X-axis Y-axis

11. Building a titration curve via calculations Comparison of a titration of a strong acid vs. a weak acid Region x-axis (mL of acid/base) 0.1 M NaOH y-axis (pH) 100 mL of 0.1 M HCl y-axis (pH) 100 mL of 0.1 M HF Initial pH 012.10 Before the equivalence point (1/2 equiv. point) 501.473.16 equivalence point 10077.93 After the equivalence point 15012.3

14. Titration of a polyprotic acid http://www.creative-chemistry.org.uk/alevel/module4/documents/N-ch4-05.pdf

15. Give the identity and concentration of the titrated sample (50 mL) represented by the blue line. KbKb Hydroperoxide 4.2 x 10 -3 Ammonia 1.8 x 10 -5 Hypochlorite 2.86 x 10 -7 Pyridine 1.5 x 10 -9 Aniline 4 x 10 -10

16. Optional Spring Break Quizzes 1. 1-page essay - how chemistry impacted you during spring break Both due on Monday after Spring Break

17. 4. (10 points) Given the following titration curve, what is the concentration of a 25-mL weak acid solution titrated with 0.1 M NaOH?