University:
The University Of Western Ontario
Course:
2223B | Organic Chemistry of Biological Molecules
Academic year:

2023
Views:

319

Pages:

2
Author:

Cole M

Titrations Acid-Base Titrations: Titration is a procedure in order to determine the concentration of a solution, however the volume is known Titrant is the solution of known concentration, which is added to another solution whose concentration has to be determined Titrand or Analyte is the solution whose concentration has to be determined You do however need an indicator and a base/acid in order to determine the concentration of the acid/base respectively End point of the titration is when the solution finally changes color Need to use the change in volume in order to find the concentration of the original solution Calculate the moles used and use the equation ratios in order to find out how many moles were neutralized Concentration equation: m1v1 = m2v2 Worked Problem: Determining Solute Concentration by Acid-Base Titration This case, there was not an even amount of stoichiometric moles (2HCl and Ba(OH)2) Titration of a Strong Acid with a Strong Base: Remember, strong acids dissociate 100%, meaning that its concentration is equal to the [H+], so just plug it into -log[H+] = pH Equivalence point is reached once there is enough acid/base to neutralize one another (equal moles of one another and solution only contains salt and water Titration of a Weak Acid with a Strong Base: Whenever you have a weak acid and strong base, it forms a buffer solution since the concentration of acid and conjugate base are basically equal, so you can use the henderson-hasselbalch equation Remember, pH = pKa when [A-] = [HA] Also, remember Kb is for whenever the molecule is acting as a base The equivalence point for a weak acid and strong base will be higher than 7 Acid-Base Titration Curves: Remember, weak acids have strong conjugate bases and weak bases have strong conjugate acids Strong Base and Strong Acid: Weak Acid and Strong Base: Weak Base and Strong Acid: The pH of the solution at equivalence point is dependent on the strength of the acid and strength of the base used in the titration. For strong acid-strong base titration, pH = 7 at equivalence point For weak acid-strong base titration, pH > 7 at equivalence point For strong acid-weak base titration, pH < 7 at equivalence point Titration Curves & Acid-Base Indicators: You want an indicator that changes color around your equivalence point Redox Titration: Once color changes, this is the end point of the titration meaning you’ve reacted every mole of whatever was present within the flask Use moles and concentrations in order to convert back and forth to find the unknown concentration