Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

Just as is the negative logarithm of , is the negative logarithm of , The Hender

ID: 632706 • Letter: J

Question

Just as is the negative logarithm of , is the negative logarithm of ,

The Henderson-Hasselbalch equation is used to calculate the of buffer solutions:

Notice that the of a buffer has a value close to the of the acid, differing only by the logarithm of the concentration ratio . Part A Acetic acid has a of . Three acetic acid/acetate buffer solutions, A, B, and C, were made using varying concentrations:

  1. ten times greater than ,
  2. ten times greater than , and
  3. .

Match each buffer to the expected .

Drag each item to the appropriate bin. SubmitHintsMy AnswersGive UpReview Part Correct Part B How many grams of dry need to be added to 2.10 of a 0.500 solution of ammonia, , to prepare a buffer solution that has a of 8.76? for ammonia is . Express your answer numerically in grams to three significant figure

Explanation / Answer

pOH = 14 - 8.76 = 5.24

pKb = 4.74


5.32 - 4.74 = 0.5


10^0.5 = 3.16 = [NH4+]/ 0.500


[NH4+] = 0.500 x 3.16=1.58 M


moles NH4+ = 1.58 x 2.10 L=3.318


moles NH4Cl = 3.318 x 53.492 g/mol=177.486 g