All Flashcards
What is the effect of adding a strong acid to a buffer solution?
The conjugate base in the buffer reacts with the added acid, neutralizing it and minimizing the change in pH.
What is the effect of adding a strong base to a buffer solution?
The weak acid in the buffer reacts with the added base, neutralizing it and minimizing the change in pH.
What is the effect of diluting a buffer solution?
The pH of the buffer remains relatively constant, as the ratio of [A-]/[HA] does not change significantly.
What happens when [A-] = [HA]?
The log term in the Henderson-Hasselbalch equation becomes zero, and pH = pKa, resulting in the strongest buffer action.
What happens when the concentrations of the acid or base exceed the buffer capacity?
The buffer's ability to resist pH changes is overwhelmed, and the pH changes significantly.
Difference between Ka and pKa.
Ka: Acid dissociation constant, measures acid strength (higher = stronger). pKa: -log(Ka), also measures acid strength (lower = stronger).
Difference between a strong acid and a weak acid in the context of buffers.
Strong Acid: Completely dissociates in solution, not suitable for buffers. Weak Acid: Partially dissociates, forms a buffer with its conjugate base.
Difference between using molarity and moles in the Henderson-Hasselbalch equation.
Molarity: Can be used if the volumes of the acid and conjugate base solutions are the same, so the volume cancels out in the ratio. Moles: Can always be used, regardless of volume, as the ratio is what matters.
Difference between equivalence point and half-equivalence point in a titration.
Equivalence Point: Moles of acid = moles of base. Half-Equivalence Point: Moles of acid = moles of conjugate base, pH = pKa.
Difference between acid and conjugate base.
Acid: Donates a proton (H+). Conjugate Base: Accepts a proton (H+).
Steps to find pH of a buffer (directly stated).
- Calculate pKa. 2. Apply the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]).
Steps to find pH during a titration using the Henderson-Hasselbalch equation.
- Write the net ionic equation. 2. Use stoichiometry to determine the amounts of acid and conjugate base after the reaction. 3. Apply the Henderson-Hasselbalch equation.
How to calculate pKa from Ka?
pKa = -log(Ka)
How to determine the concentrations of acid and conjugate base after the addition of a base in a titration?
Use stoichiometry based on the balanced net ionic equation to determine the remaining moles of acid and the moles of conjugate base formed.
Steps to determine pH using ICE table.
- Set up an ICE (Initial, Change, Equilibrium) table. 2. Write the Ka expression. 3. Solve for [H+]. 4. Calculate pH = -log[H+].