Chapter 16 - Buffers Flashcards
A buffer contains a (weak/strong) acid/base and its conjugate base/acid
weak
The base/acid ratio should be between …
0.10-10
adding base to a solution would (increase/decrease) the pH
increase
adding acid to a solution would (increase/decrease) the pH
decrease
a buffer is most effective when concentrations of acid and base are (equal/different)
equal
a buffer is most effective when concentrations of acid and conjugate base are (low/high)
high
the effective range for a buffering system is ____ pH unit on either side of pKa
one
the amount of acid or base that you can add to a buffer without causing a large change in pH
buffer capacity
buffer capacity increases with (increasing/decreasing) absolute concentrations of the buffer components
increasing
overall buffer capacity (increases/decreases) as the relative concentrations of the buffer components become more similar to each other
increases
molar solubility
solubility in units of moles per liter
the solubility of an ionic compound is (higher/lower) in a solution containing a common ion than in pure water
lower
the solubility of an ionic compound with a strongly basic or weakly basic anion (increases/decreases) with increasing acidity (decreasing pH)
increases
the solution is unsaturated and more of the solid ionic compound can dissolve in the solution
Q
the solution is saturated. the solution is holding the equilibrium amount of the dissolved ions and additional solid does not dissolve in the solution
Q = Ksp
the solution is super saturated. under most circumstances, the excess solid precipitates out of a super saturated solution
Q > Ksp
the equilibrium constant associated with the reaction for the formation of a complex ion
formation constant (Kf)
the solubility of an ionic compound containing a metal cation that forms complex ions (increases/decreases) in the presence of Lewis bases that complex with the cation
increases
Stuff to know:
- we can determine the pH of a buffer solution by solving an equilibrium problem, focusing on the common ion effect, or by using the Henderson-Hasselbalch equation
what is Ksp?
the solubility product constant - an equilibrium constant for the dissolution of an ionic compound in water