Transcript Ch. 14 - Liquids

The ratio of the concentration of the
dissociated form of an acid to the
concentration of the undissociated form.
[ H  ][ A ]
Ka 
[ HA]
 H2CO3(aq) + H2O(l)  H3O+ + HCO3


[H3O ][HCO3 ]
Ka 
[H2CO3 ]

Larger Ka, the stronger the acid.
Chemical reaction between an acid
and a base.
 Products are a salt (ionic compound)
and water.

ACID + BASE  SALT + WATER
HCl + NaOH  NaCl + H2O
strong
strong
neutral
HC2H3O2 + NaOH  NaC2H3O2 + H2O
weak
strong
basic
• Salts can be neutral, acidic, or basic.
• Neutralization does not mean pH = 7.

Titration
standard solution
› Analytical method in
which a standard
solution is used to
determine the
concentration of an
unknown solution.
unknown solution

Equivalence point (endpoint)
› Point at which equal amounts of
H3O+ and OH- have been added.
› Determined by…
 indicator color change
• dramatic change in pH
+
O
moles H3 = moles
MVn = MVn
M: Molarity
V: volume
n: # of H+ ions in the acid
or OH- ions in the base
OH

42.5 mL of 1.3M KOH are required to
neutralize 50.0 mL of H2SO4. Find the
molarity of H2SO4.
H3O+
OH-
M=?
M = 1.3M
V = 50.0 mL
n=2
V = 42.5 mL
n=1
MV# = MV#
M(50.0mL)(2)
=(1.3M)(42.5mL)(1)
M = 0.55M H2SO4
A solution of a weak acid and a weak
base that resists large pH changes when
acid or base is added.
 Buffer capacity: amount of acid or base
that can be added without changing
the pH

› Buffered Aspirin
› Bufferin