Determining Ka of Weak Acid
Watch:
https://www.youtube.com/watch?v=y3Oa0L404oM&ab_channel=CampusNews%26Education
https://www.youtube.com/watch?v=tvCyrBHJfBk&ab_channel=chemistNATE
Read: Your lab guide (VERY important) and lab manual
Complete: Lab Report below (attach your graphs)
Answer:
At one-half the equivalence point of an acid base titration, the pH is equal to the ______.
What indicator is being used in this titration? ___________________
What pH do we expect at the equivalence point of this titration of a weak acid and strong base?
Acidic
Basic
Neutral
The shape of a titration curve ,since based on the logarithmic scale, best resembles which letter?
S
L
U
I
Data:
TRIAL 1
TRIAL 2
mL NaOH
pH
mL NaOH
pH
0
3.08
0
3.10
0.50
3.35
0.6
3.37
2.4
3.80
2.8
3.82
3.7
4.00
3.6
4.05
4.4
4.05
4.3
4.10
5.8
4.20
5.4
4.25
7.3
4.28
7.1
4.32
8.9
4.39
8.6
4.44
10.7
4.49
10.2
4.52
12.8
4.62
12.6
4.66
14.6
4.72
15.0
4.75
15.8
4.78
16.0
4.85
17.4
4.88
17.7
4.91
19.9
5.05
20.1
5.08
20.9
5.15
21.4
5.20
22.4
5.31
22.0
5.33
23.7
5.50
23.8
5.52
24.4
5.65
24.5
5.68
24.7
5.75
24.9
5.80
25.1
6.00
25.5
6.12
25.8
6.30
26.0
6.35
26.0
6.75
26.3
7.80
26.2
7.45
26.3
7.49
26.3
8.85
26.5
8.90
27.0
10.40
27.0
10.44
27.3
10.55
27.3
10.61
28.2
10.85
28.5
10.88
29.9
10.95
30.0
11.00
30.1
11.05
30.2
11.10
31.5
11.15
32.6
11.20
32.7
11.24
32.9
11.35
Graph each set of data!
Indicate how you arrived at the volumes you entered below by indicating the volume Volume @ Equivalence Point and Volume @ ½ Equivalence Point on our graphs (draw dotted lines, use color, etc).
Complete the table (show calculations below it):
Determined from Graphs
Trial 1
Trial 2
Volume @ Equivalence Point
Volume @ ½ Equivalence Point
pKa
Ka
Average Ka for both trials
Calculations
Trial 1 Ka:
Trial 2 Ka:
Average Ka: