TBR Chemistry Ch. 5 Exam Questions & Answers 2024

TBR Chemistry Ch. 5 Exam Questions & Answers 2024 Buffer - ANSWER-a solution where pH remains relatively constant after the addition of either strong acid or strong base. Can be made by combining a conjugate pair in roughly equal mole portions (must be weak acid/base pair). The addition of strong base or strong acid shifts teh ratio of weak acid (HA) to its conjugate base (A⁻), but the pH does not change, if the A⁻:HA ratio is close to 1.0 Can also be made by partially titrating a weak acid with roughly half of an equivalent of strong base, or by partially titrating a weak conjugate base with roughly half of an equivalent of strong acid. Neutralization - ANSWER-The mixing of equal mole portions of an acid with a base, regardless of their concentrations and strengths. Neutralized solution has equal moles of hydroxide ion and hydronium ion. Neutralization does not mean to make the pH of the solution equal to 7. Equivalence point - ANSWER-The pH is not always 7 at the equivalent point of a titration. For a weak acid titrated by a strong base, the equivalence point is the point at which it is completely converted into its conjugate base. The conjugate base will yield a pH greater than 7, so the pH is greater than 7 at the equivalence point. pH range for buffers - ANSWER-According to convention the ratio of weak acid and weak conjugate base cannot exceed 10:1 (or 1:10). The range is pKa±1 Henderson-Hasselbalch Equation - ANSWER-pH = pKa + log([A⁻]/[HA])