CHEM 1A Lecture 27: 12-02 Lecture 27

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browncod58

2 Dec 2016

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UCSB

Department

Chemistry and Biochemistry

Course

CHEM 1A

Professor

Joseph

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Titrating weak acid with a strong base. This is in the middle of the buffer region. Major differences between a strong acid and a weak acid-strong titration curve with a strong base. :: \lled the buffer region, appears before the steep rise to the equivalence point. z,. The ph at the equivalence point is greater than 7. 00. Assume 0. 1 eq base has been added to a fully protonated solution of acetic acid. The henderson-hasselbalch equation can be used to calculate the ph of the solution: Ph = pka + {log [a-] / [ha]} must be between -1 and 1. Ph = pka + log [0. 1] / [0. 9] Both a weak acid, ha, and its conjugate base, a-, in solution. Both a weak base and its conjugate acid in solution. Ph = pka + log [a-] / [ha] The loss of each mole of h+ shows up as separate equivalence point.

Related Questions

Â± Titration of Weak Acid with Strong Base A titration involves adding a reactant of known quantity to a solution of an another reactant while monitoring the equilibrium concentrations. This allows one to determine the concentration of the second reactant. The equation for the reaction of a generic weak acid HA with a strong base is HA(aq)+OHâ(aq)âAâ(aq)+H2O(l) A certain weak acid, HA, with a Ka value of 5.61Ã10â6, is titrated with NaOH. Part A A solution is made by titrating 9.00 mmol (millimoles) of HA and 3.00 mmol of the strong base.

What is the resulting pH? Express the pH numerically to two decimal places. pH =

Part B More strong base is added until the equivalence point is reached. What is the pH of this solution at the equivalence point if the total volume is 57.0 mL ? Express the pH numerically to two decimal places. pH = Submit

Sketch the titration curve for a weak acid titrated with a strong base.

When performing calculations concerning weak acid-strong base titrations, the general two-step procedure is to solve a stoichiometry problem first, then to solve an equilibrium problem to determine the pH. What reaction takes place in the stoichiometry part of the problem? What is assumed about this reaction?

At the various points in your titration curve, list the major species present after the strong base (NaOH), for example reacts to completion with the weak acid, HA. What equilibirum problem would you solve at the various points in your titration curve to calculate pH? Why is pH at> 7.0 at the equivalence point of a weak acid-strong base titration? Does the pH at halfway poin the equivalence point have to be less than 7.0? what does the pH at the half-way point equal? Compare and contrast the titration curves for a strong acid-strong base titration and a weak acid-strong base titration.

graycat703

Sketch the titration curve for a weak acid titrated by a strong base. When performing calculations concerning weak acid–strong base titrations, the general two-step procedure is to solve a stoichiometry problem first, then to solve an equilibrium problem to determine the pH. What reaction takes place in the stoichiometry part of the problem? What is assumed about this reaction?

At the various points in your titration curve, list the major species present after the strong base (NaOH, for example) reacts to completion with the weak acid, HA. What equilibrium problem would you solve at the various points in your titration curve to calculate the pH? Why is pH is greater than 7.0 at the equivalence point of a weak acid-strong base titration? Does the pH at the halfway point to equivalence have to be less than 7.0? What does the pH at the halfway point equal? Compare and contrast the titration curves for a strong acid–strong base titration and a weak acid–strong base titration.

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CHEM 1A Lecture 27: 12-02 Lecture 27

CHEM 1A Full Course Notes

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