Tris(hydroxymethyl)aminomethane, commonly called TRIS or Trizma, is often used as a buffer in biochemical studies. Its buffering range is pH 7 to 9, and K₁ is1.19 x 10-6 for the aqueous reaction(HOCH2)3 CN H2 + H₂O ⇒ (HOCH2)3 CN H3 + + OH™TRISTRISH+a. What is the optimal pH for TRIS buffers?pHb. Calculate the ratio [TRIS]/[TRISH+]at pH = 7.00[TRIS][TRISH+]= 9.00.[TRIS]TRISH+](Simplify your answer completely.)c. A buffer is prepared by diluting 50.0 g TRIS base and 35.0 g TRIS hydrochloride (written as TRISHCl) to a total volume of 2.0 L. What is the pH ofthis buffer?pH =What is the pH after 0.50 mL of 12 M HCl is added to a 200.0-mL portion of the buffer?pH =and at pH

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ris(hydroxymethyl)aminomethane, commonly called TRIS or Trizma, is often used as a buffer in biochemical studies. Its buffering range is pH 7 to 9, and K₁ is .19 x 10-6 for the aqueous reaction (HOCH2)3 CN H2 + H₂O (HOCH₂)3 CN H3+ + OH¯ TRIS TRISH+ a. What is the optimal pH for TRIS buffers? pH = b. Calculate the ratio [TRIS]/[TRISH+] at pH = 7.00 [TRIS] TRISH and at pH=9.00. [TRIS] [TRISH+] (Simplify your answer completely.) c. A buffer is prepared by diluting 50.0 g TRIS base and 35.0 g TRIS hydrochloride (written as TRISHCl) to a total volume of 2.0 L. What is the pH of this buffer? pH = What is the pH after 0.50 mL of 12 M HCl is added to a 200.0-mL portion of the buffer? pH =

ris(hydroxymethyl)aminomethane, commonly called TRIS or Trizma, is often used as a buffer in biochemical studies. Its buffering range is pH 7 to 9, and K₁ is .19 x 10-6 for the aqueous reaction (HOCH2)3 CN H2 + H₂O (HOCH₂)3 CN H3+ + OH¯ TRIS TRISH+ a. What is the optimal pH for TRIS buffers? pH = b. Calculate the ratio [TRIS]/[TRISH+] at pH = 7.00 [TRIS] TRISH and at pH=9.00. [TRIS] [TRISH+] (Simplify your answer completely.) c. A buffer is prepared by diluting 50.0 g TRIS base and 35.0 g TRIS hydrochloride (written as TRISHCl) to a total volume of 2.0 L. What is the pH of this buffer? pH = What is the pH after 0.50 mL of 12 M HCl is added to a 200.0-mL portion of the buffer? pH =

Chemistry: Principles and Practice

3rd Edition

ISBN:9780534420123

Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward Mercer

Publisher:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward Mercer

Chapter16: Reactions Between Acids And Bases

Section: Chapter Questions

Problem 16.89QE

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Sketch a titration curve for the titration of potassium hydroxide with HCl, both 0.100 M. Identify three regions in which a particular chemical species or system dominates the acid-base equilibria.
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For conjugate acidbase pairs, how are Ka and Kb related? Consider the reaction of acetic acid in water CH3CO2H(aq)+H2O(l)CH3CO2(aq)+H3O+(aq) where Ka = 1.8 105 a. Which two bases are competing for the proton? b. Which is the stronger base? c. In light of your answer to part b. why do we classify the acetate ion (CH3CO2) as a weak base? Use an appropriate reaction to justify your answer. In general, as base strength increases, conjugate acid strength decreases. Explain why the conjugate acid of the weak base NH3 is a weak acid. To summarize, the conjugate base of a weak acid is a weak base and the conjugate acid of a weak base is a weak acid (weak gives you weak). Assuming Ka for a monoprotic strong acid is 1 106, calculate Kb for the conjugate base of this strong acid. Why do conjugate bases of strong acids have no basic properties in water? List the conjugate bases of the six common strong acids. To tie it all together, some instructors have students think of Li+, K+, Rb+, Cs+, Ca2+, Sr2+, and Ba2+ as the conjugate acids of the strong bases LiOH, KOH. RbOH, CsOH, Ca(OH)2, Sr(OH)2, and Ba(OH)2. Although not technically correct, the conjugate acid strength of these cations is similar to the conjugate base strength of the strong acids. That is, these cations have no acidic properties in water; similarly, the conjugate bases of strong acids have no basic properties (strong gives you worthless). Fill in the blanks with the correct response. The conjugate base of a weak acid is a_____base. The conjugate acid of a weak base is a_____acid. The conjugate base of a strong acid is a_____base. The conjugate acid of a strong base is a_____ acid. (Hint: Weak gives you weak and strong gives you worthless.)
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