Wednesday
July 23, 2014

Homework Help: CHEMISTRY FOR DR. BOB or anyone else

Posted by Delli on Friday, May 11, 2007 at 12:38pm.

A hypothetical weak acid HA, was combined with NaOH in the following proportions: 0.20 mol HA, 0.08 mol NaOH. The mixture was then diluted to a total volume of 1L, and the pH measured.

(a) If pH=4.80, what is the pKa of the acid

(b) how many additional moles of NaOH should be added to the solution to increase the pH to 5.00

HA + NaOH ==> NaA + HOH

0.2 mol HA to begin.
0.08 mol NaOH used to neutralize.
0.2-0.08 = 0.12 mol HA reamins.
0.08 mol A^- formed.
M = mols/L.
Ka = (H^+)(A^-)/(HA)
You know (H^+), from pH, you know A^- and you know HA. Solve for Ka, then pKa. Post your work if you get stuck.

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

CHEMISTRY FOR DR. BOB or anyone else - A hypothetical weak acid HA, was combined...
biology - suppose 23mL of NaOH was required. How much Carbonic Acid was ...
Inorganic chemistry - mol KHP = (0.7719g)(1 mol KHP/204.2g) = .0038mol Where are...
CHEM - Which of the following mixtures will result in the formation of a buffer ...
chemistry - Which of the following mixtures will be a buffer when dissolved in a...
General Chemistry - Starting out with 50 mL of 0.20 M NaHCO3, calculate how many...
chemistry - A chemist wishes to prepare 250mL of a buffer that is pH = 4.50. ...
Chemistry(Please check) - Which of the following mixtures will be a buffer when ...
Dr Bob - What is the pH of the solution that results from mixing 5 ml of 0.2 M ...
Chemistry II - A 12.00 mL sample of sulfuric acid from an automobile battery ...

Search
Members