All Flashcards
Define pH.
pH = -log[H+], a measure of the acidity or basicity of a solution.
Define pKa.
pKa = -log(Ka), a measure of acid strength; lower pKa indicates a stronger acid.
Define pOH.
pOH = -log[OH-], a measure of the hydroxide ion concentration in a solution.
Define Ka.
Acid dissociation constant, a measure of the strength of an acid in solution.
Define Buffer.
A solution that resists changes in pH when small amounts of acid or base are added. Consists of a weak acid and its conjugate base.
Define Equivalence Point.
The point in a titration where the amount of titrant added is stoichiometrically equivalent to the amount of analyte being titrated.
Define Acid-Base Indicator.
A substance that changes color depending on the pH of the solution, used to signal the endpoint of a titration.
What is the effect of decreasing the pKa value of an acid?
The acid becomes stronger.
What is the effect of adding a strong acid to a buffer solution?
The buffer resists drastic pH change by reacting with the added acid.
What happens when [A-] = [HA] in a buffer solution?
pH = pKa, and the buffer is at its strongest.
What happens if you choose an indicator with a pKa far from the equivalence point?
The endpoint of the titration will not accurately reflect the equivalence point.
What is the effect of diluting a buffer solution?
The pH remains relatively constant, but the buffer capacity decreases.
What happens to the pH of a solution as the concentration of H+ ions increases?
The pH decreases.
What are the key differences between pH and pKa?
pH: Measures the acidity/basicity of a solution. | pKa: Measures the strength of an acid.
Compare strong acids and weak acids in terms of pKa.
Strong acids: Have very low or negative pKa values. | Weak acids: Have higher pKa values.
Differentiate between Ka and pKa.
Ka: Acid dissociation constant (linear scale). | pKa: -log(Ka) (logarithmic scale).
Compare the pH at the half-equivalence point and the equivalence point in a weak acid titration.
Half-equivalence point: pH = pKa of the weak acid. | Equivalence point: pH depends on the conjugate base hydrolysis and is usually > 7.
Compare the effective range of an indicator and its pKa.
Effective Range: The pH range where the indicator changes color (pKa ± 1). | pKa: The pH at which the indicator is exactly halfway between its two colors.