Acids and Bases
October 17, 1996 Name ____________________________
Here is a table of Acid Dissociation Constants at 25deg. C. Values are given in the "E" style of scientific notation, i.e. 1.75E-05 is 1.75 x 10-5.
Name
|
K1
(or Ka)
|
K2
|
K3
|
K4
|
| Acetic
acid
|
1.75E-05
|
|||
| Ammonium
ion
|
5.70E-10
|
|||
| Arsenic
acid (H3AsO4)
|
5.8E-03
|
1.10E-07
|
3.2E-12
|
|
| Benzoic
acid
|
6.8E-05
|
|||
| Pyridinium
ion (C5H5NH+)
|
5.9E-06
|
|||
| Carbonic
acid
|
4.45E-07
|
4.69E-11
|
||
| o-Phthalic
acid
|
1.12E-03
|
3.90E-06
|
1. For each substance below, state if it is a Strong Acid (SA), Strong Base (SB), Weak Acid (WA), Weak Base (WB), Buffer (Buffer), or Amphiprotic (Amphiprotic). As a first approximation, certain species of polyprotic acids and some mixtures can be considered to fall into one of these categories also.
Substance
|
What
is it?
|
Substance
|
What
is it?
|
| Acetic
Acid
|
CH3COONa
|
||
| "KHP"
(P=phthalate)
|
Pyridine
hydrochloride
|
||
| CO2
in water
|
HNO3
|
||
| Sodium
Benzoate
|
0.001M
KOH
|
||
| 0.1M
NH3 + 0.2M NH4+
|
0.1M
NaOH + 0.01M NH3
|
2. Calculate the pH of 0.001 M KOH.
3. Calculate the pH of 0.15M sodium acetate.
4. Calculate the pH of 0.001M Benzoic Acid.
5. 50.0 mL of a buffer consisting of 0.100M acetic acid and 0.200 M sodium acetate is about to be hit with 2.0 mL of 0.100 M HCl.
A. Calculate the pH of the buffer before the HCl is added.
B. Use an Initial/Final Spreadsheet to calculate the pH of the solution after the HCl has been added. (It may or may not still be a buffer.)
Balanced Chemical Reaction: ________________________________________________
CH3COOH
|
CH3COO-
|
H+
(HCl)
|
Volume
| |
| Initial
mmoles
|
||||
Final mmoles
|
||||
Molarity
|
6. Sketch the titration curve of 50.0 mL of 0.0500 M pyridinium chloride with 0.100 M NaOH.