ECON 102 Midterm: ECON 102 UW Madison 1 MidtermSpring2010scott
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Please state any additional assumptions you made, and show all work. If you don"t have time to complete a section, please describe how you would solve the problem (without using a computer program such as mineql). 1 joule = 0. 239 calories: buffers (25%) You have prepared a 10 mm phosphate buffer designed to hold ph at 8. 1 (25 c, assume i~0). If you were to elevate the solution ph to 12. 0, how much naoh would you need to add (again in mm): this is a good use for the empiricial henderson hasselbach equation. Where ca is the na2hpo4 and cha is the kh2po4 ph pk a log. And since ca + cha = 10 mm, 2: now determine the new mixture at ph 12 and determine amount of protons that need to be neutralized, but this time we"re closer to the third ka, so ca is po4. H+ in phosphates = 2*0. 00122+0. 00888-0. 00666 = 0. 00466m or 4. 66mm.
