CHM 2046C Module 12 Chapter 18 Sample Exam Answers

Part K: Chapter 18 Key Terms 10 points

1. _Acid-base Indicator_ – a material that is one color below a particular pH and another color above it; typically acid-base indicators are themselves weak acids or bases.

2. _Buffer Capacity – a measure of how much hydronium or hydroxide can be added to a buffer solution before the buffer can no longer control the pH.

3. _Buffer Solution – a solution that resists a change in pH when hydroxide or hydronium ions are added.

4. _Common Ion Effect_ - The limiting of acid (or base) ionization caused by the addition of its conjugate base (or conjugate acid)

.

5. _Equivalence Point_ – the point in a titration at which one reactant has been exactly consumed by the solution of the other reactant.

6. _Formation Constant_ – the equilibrium constant for the formation of a complex ion.

7. _Henderson-Hasselbalch Equation_ – equations that allows us to calculate the pH of an acid buffer or the pOH of a base buffer::

[conjugate base]

pH = pK_a + log (-------------------------)

[acid]

[conjugate acid]

pOH = pK_b + log (-------------------------)

[base]

8. _Solubility Product Constant_ – the equilibrium constant for the dissociation of a sparingly soluble salt. For the salt A_xB_y, it has the form:

K_sp = [A ^y+]^x [B ^x-]^y

9. _Titrant_ – the substance added during a titration.

10. Titration – the addition of a base to an acid (or vice versa) until the equivalence point is reached