Chapter 16 Aqueous Ionic Equilibrium

Question 1

A _________ resists pH change by neutralizing added acid or added base because it contains significant amounts of both a weak acid and its conjugate base (or a weak base and its conjugate acid).

Answer 1

buffer

Question 2

What is the Henderson-Hasselbalch Equation and when can you use it?

Answer 2

pH = pKa + log [base]/[acid]

You can use this if the “x is small” approximation is valid.

Question 3

T/F A buffer with equal amounts of acid and conjugate base (or vice versa) is more resistant to pH change and is a more effective buffer.

Answer 3

True

Question 4

T/ F A buffer is most effective when the concentrations of acid and conjugate base are highest.

Answer 4

True

Question 5

T/F The effective range for a buffering system is one pH unit on either side of pKa.

Answer 5

True

Question 6

The amount of acid or base that we can add to a buffer without destroying its effectiveness is _________.

Answer 6

Buffer capacity

Question 7

The point in the titration when the number of moles of base is stoichiometrically equal to the number of moles of acid.

Answer 7

equivalence point

Question 8

In a titration of a weak acid with a strong base, what happens halfway to the equivalence point when the buffer components are exactly equal?

Answer 8

pH = pKa

Question 9

What is the equation for solubility product constant (Ksp)?

Answer 9

Ksp = [concentration of products]

CaF2 = Ca 2+ (aq) + 2 F-
Ksp = [Ca2+][F-]^2

Question 10

The ____________ is the solubility in units of moles per liter (mol/L).

Answer 10

molar solubility

Question 11

If Q < Ksp, then _____________________

Answer 11

the solution is unsaturated and more of the solid ionic compound can dissolve in the solution.

Question 12

If Q = Ksp then _________________________

Answer 12

the solution is saturated. The solution is holding the equilibrium amount of the dissolved ions and additional solid will not dissolve in the solution.

Question 13

If Q > Ksp, then ________________________

Answer 13

the solution is supersaturated. Under most circumstances, the excess solid will precipitate out of the solution.

Question 14

A ____________ contains a central metal ion bound to one or more ligands.

Answer 14

complex ion

Question 15

A ______________ is a neutral molecule or ion that acts as a Lewis base with the central metal ion.

Answer 15

ligand

Question 16

What is the equation for the formation constant (Kf)?

Answer 16

Kf = [product]/ [reactant][reactant]