An unknown student takes an unknown mass of an unknown weak monoprotic acid and dissolves it in an unknown amount of water. The unknown student then divides the aqueous solution into two equal volumes, titrates one volume to a phenolphthalein endpoint, and then adds the other volume to the titrated solution. The pH of the combined volumes turns out to be 4.67. The Ka of the weak acid is

An unknown student takes an unknown mass of an unknown weak monoprotic acid and dissolves it in an unknown amount of water. The unknown student then divides the aqueous solution into two equal volumes, titrates one volume to a phenolphthalein endpoint, and then adds the other volume to the titrated solution. The pH of the combined volumes turns out to be 4.67. The Ka of the weak acid is

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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A formic acid buffer is prepared with 0.010 M each of formic acid (HCOOH) and Sodium formate (NaCOOH). The Ka for formic acid is 1.8 x 10-4. What is the pH of the solution? What is the pH if 0.0020 M of solid sodium hydroxide (NaOH) is added to a liter of buffer? What would be the pH of the sodium hydroxide solution without the buffer? What would the pH have been after adding sodium hydroxide if the buffer concentrations had been 0.10 M instead of 0.010 M?
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An analytical chemist is titrating 94.2 mL of a 0.4600M solution of dimethylamine ((CH,),NH) with a 0.2300M solution of HNO,. The p K, of dimethylamine is 3.27. Calculate the pH of the base solution after the chemist has added 121.9 mL of the HNO, solution to it. Note for advanced students: you may assume the final volume equals the initial volume of the solution plus the volume of HNO, solution added. Round your answer to 2 decimal places. pH =||
Imagine that a 50.0 mM MES buffer is made by dissolving an appropriate mass of solid MES in water, adding NaOH ("titrating") until 60.0% of the MES is converted to its conjugate base, then diluting to the required final volume Write the net ionic equation for the reaction that occurs when a little HCl is added to this buffer, then calculate the pH that results when 1.00 mL of 0.250 M HCI is added to 50.0 mL of buffer Calculate the pH that results when 1.00 mL of 0.250 M NaOH is added to 50.0 mL of this buffer. Why does the pH change more when you add NaOH then when you add the same amount of HCI? Calculate the pH that results when 5.00 mL of 0.250 M NaOH is added to 50.0 mL of this buffer.