All Flashcards
Define 'analyte' in titration.
The solution with the unknown concentration in a titration.
Define 'titrant' in titration.
The solution with the known concentration that is added to the analyte in a titration.
Define 'equivalence point'.
The point in a titration where the moles of titrant added equals the moles of analyte in the solution.
Define 'titration curve'.
A plot of pH change versus the volume of titrant added during a titration.
Define 'half-equivalence point'.
The point in a weak acid/base titration where half of the acid/base has been neutralized, resulting in pH = pKa or pOH = pKb.
Define 'buffer'.
A solution that resists changes in pH due to the presence of a weak acid and its conjugate base, or a weak base and its conjugate acid.
What is the effect of adding excess OH- after the equivalence point?
The solution becomes basic, and the pH increases.
What is the effect of having a buffer solution during a titration?
The solution becomes less responsive to pH changes.
What happens if you use an indicator with a pH range that does not include the equivalence point?
The endpoint of the titration will not accurately reflect the equivalence point, leading to inaccurate results.
What is the effect of using a burette that is not properly calibrated?
The volume measurements will be inaccurate, leading to errors in the calculated concentration of the analyte.
What is the effect of not balancing the chemical equation before performing titration calculations?
The stoichiometric coefficients will be incorrect, leading to an incorrect calculation of the unknown concentration.
What happens when a weak acid is titrated with a strong base?
A conjugate base is formed, affecting the pH at the equivalence point, making it basic.
Compare strong acid-strong base and weak acid-strong base titrations.
Strong Acid-Strong Base: Equivalence point pH is 7, no buffer region. Weak Acid-Strong Base: Equivalence point pH is >7, has a buffer region before the equivalence point.
Compare the pH at the equivalence point for titrations involving weak acids/strong bases versus strong acids/strong bases.
Weak acid/strong base: pH > 7 at equivalence point. Strong acid/strong base: pH = 7 at equivalence point.
What is the difference between the equivalence point and the half-equivalence point in a titration?
Equivalence point: Moles of titrant = moles of analyte. Half-equivalence point: Half the volume to reach the equivalence point; pH = pKa (or pOH = pKb) for weak acids/bases.
Compare titrating a weak acid with a strong base versus titrating a weak base with a strong acid.
Weak acid with strong base: pH at equivalence point is basic. Weak base with strong acid: pH at equivalence point is acidic.
Compare the shapes of titration curves for strong acid-strong base titrations versus weak acid-strong base titrations.
Strong acid-strong base: Sharp, abrupt change in pH near the equivalence point. Weak acid-strong base: More gradual change in pH, buffer region present, less sharp change at the equivalence point.