Exploring Buffers and
Buffer Capacity
REBECCA FORLOINE
LAB PARTNER: TERRENCE CONNORS
FEBRUARY 17, 2015
Having read the Georgia Institute of Technology Academic Honor code, I
understand and accept my responsibility as a member of the Georgia Tech
Community to uphold the Academic Honor Code at all times. In addition, I
understand my options for reporting honor violations as detailed in the code.
Data and Results
A.
Data Tables and Plots
a.
Sodium Acetate/Acetic Acid Buffer
i.
Table 1. Data for Acidic Buffer
Assigned pH
5.2
Mass Sodium Acetate Trihydrate
(g)
3.97
Measured pH
5.22
ii.
Procedure and Results 1. Base Capacity of Acidic Buffer
1.
In 4 separate test tubes combine (1) 1mL of 0.5M HCl and
10mL of buffer, (2) 1mL of 0.5M NaOH to 10mL of buffer, (3)
1mL of 0.5M HCl to 20mL of buffer, and (4) 1mL of 0.5M
NaOH to 20mL of buffer.
Calculate the pH of the solutions.
2.
Use the balanced equations for the reaction of the buffer with
the strong acid and the strong base, along with the Henderson-
Hasselbalch equation to calculate the new pH of the solution.
Compare predictions with actual results.
The measured pH
values are listed below:
Solution
pH
1mL HCl and 10mL of buffer
5.10
1mL NaOH and 10mL buffer
5.88
1mL HCl and 20mL of buffer
5.25
1mL NaOH and 20mL buffer
5.64
iii.
Procedure and Results 2. Base Capacity of Water a Control
1.
In 4 separate test tubes combine (1) 1mL of 0.5M HCl and
10mL of deionized water, (2) 1mL of 0.5M NaOH and 10mL of
deionized water, (3) 1mL of 0.5M HCl and 20mL of deionized
water, and (4) 1mL of 0.5M NaOH and 20mL of deionized
water.
The resulting pH is recorded below:
Solution
pH
1mL HCl and 10mL of water
2.93
1mL NaOH and 10mL water
13.75
1mL HCl and 20mL of water
3.16
1mL of HCl and 20mL water
13.27
b.
Sodium Bicarbonate, Sodium Carbonate buffer
i.
Table2. Data for Basic Buffer
