1 / 24

Drill: Determine the pH of 0.25 M HZ. K aHZ = 2.5 x 10 -7

Drill: Determine the pH of 0.25 M HZ. K aHZ = 2.5 x 10 -7. Buffer Solutions. Buffer Solution. A solution that resists changes in pH. Buffer Solution. Made from the combination of a weak acid & its salt. Buffer Solution. Made from the combination of a weak base & its salt. Buffer Examples.

tudor
Download Presentation

Drill: Determine the pH of 0.25 M HZ. K aHZ = 2.5 x 10 -7

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Drill: Determine the pH of 0.25 M HZ.KaHZ = 2.5 x 10-7

  2. Buffer Solutions

  3. Buffer Solution • A solution that resists changes in pH

  4. Buffer Solution • Made from the combination of a weak acid & its salt

  5. Buffer Solution • Made from the combination of a weak base & its salt

  6. Buffer Examples • Mix acetic acid & sodium acetate • Mix ammonia & ammonium chloride

  7. Buffer Solution • A buffer solution works best when the acid to salt ratio is • 1 : 1

  8. Buffer Solution • A buffer solution works best when the base to salt ratio is • 1 : 1

  9. Buffer Solution • The buffering capacity of a solution works best when the pH is near the pKa

  10. pKa or pKb • pKa = - log Ka • pKb = - log Kb

  11. Buffer Problems • Calculate the pH of a solution containing 0.10 M HAc in 0.10 M NaAc: Ka = 1.8 x 10-5

  12. Buffer Problems • Calculate the pH of 0.10 M NH3 in 0.20 M NH4NO3: • Kb = 1.8 x 10-5

  13. Buffer Problems Calculate the pH of a solution containing 0.10 M HBz in 0.20 M NaBz: Ka = 6.4 x 10-5

  14. Buffer Problems Calculate the pH of a solution containing 0.50 M HQ in 0.10 M NaQ: Ka = 4.0 x 10-5

  15. Drill Calculate the pH of a solution containing 0.30 M HZ in 0.10 M NaZ: Ka = 3.0 x 10-5

  16. Lab Requirements • To make accurate measurements, we must have solutions with accurately measured concentrations

  17. Standard Solution • A solution with known concentration • 2.004 M HCl

  18. STD Problems Calculate the mass of KHP (MW = 204.23) required to make 1.0 L of 0.100 M KHP

  19. Henderson-Hasselbach Eq [A-] [HA] pH = pKa + log

  20. Henderson-Hasselbach Eq [B+] [B] pOH = pKb+ log

  21. Buffer Problems • Calculate the salt to acid ratio to make a buffer solution with pH = 5.0 • Ka for HBZ = 2.0 x 10-5

  22. Buffer Problems Calculate the salt to base ratio to make a buffer solution with pH = 9.48 • Kb for MOH = 2.0 x 10-5

  23. Calculate the HCO3- to H2CO3 ratio in blood with pH = 7.40 • Ka1 for H2CO3 = 4.4 x 10-7

  24. 150 ml of 0.10 M NaOH is added to 100.0 ml of 0.10 M H2CO3. Calculate all. • Ka1 for H2CO3 = 4.4 x 10-7 • Ka2 for H2CO3 = 4.7 x 10-11

More Related