E.
Reflection
1.Did you see the expected number of equivalence points for a triprotic acid? Why or why not?
2.
How did the concentration of H
3
PO
4
determined from each of the equivalence points
compare? Explain any difference or similarity.
The two equivalence point concentrations for the H
3
PO
4
solution titration were fairly close.
The first equivalence point concentration was 0.043 M and the second equivalence point
concentration was 0.053 M. This is a difference of 0.010 M, a percent error of 23 % when
going from 0.043 to 0.053, and a percent error of -19 % when going from 0.053 to 0.043. The
equivalence point concentrations for the H
3
PO
4
in the soft drink titration of SodaStream Dr.
Pete differed quite a bit more than those of the H
3
PO
4
solution. The first equivalence point
concentration was 0.00288 M and the second equivalence point concentration was 0.00575
M. This is a difference of 0.00287 M, a percent error of 99.7 % when going from 0.00288 to
0.00575, and a percent error of -49.9 % when going from 0.00575 to 0.00288.
3.
How did the K
a
values match those listed in your textbook? Explain any difference or
similarity.
The K
a
values listed in my textbook are fairly similar to the K
a
values that I obtained in my
experiment. The book lists K
a1
as 7.5 x 10
-3
and K
a2
as 6.2 x 10
-8
. I obtained the values of K
a1
as
5.62 x 10
-3
and K
a2
as 5.62 x 10

#### You've reached the end of your free preview.

Want to read all 3 pages?

- Winter '20
- Chemistry, pH, Pk, Soft drink, SodaStream Cherry Cola