Your Task In this investigation you will monitor the pH of an unknown diprotic acid solution as it is titrated with a standardized sodium hydroxide solution. Using the pH curve, you will determine the molar mass and identity of the unknown acid From the following list of five diprotic acids. You should confirm the identity by comparing the pH at the half-equivalence points with the accepted pKa1 and pKa2 values. Diprotic Acid Oxalic Acid Formula H2C2O4 Molecular weight 90 g/mol Ka1 Ka2 6.0 x 10-2 6.1 x 10-5 Malonic Acid H2C3H2O4 104 g/mol 1.5 x 10-3 2.0 x 10-6 Maleic Acid H2C4H2O4 116 g/mol 1.2 x 10-2 5.9 x 10-7 Malic Acid H2C4H4O5 134 g/mol 3.5 x 10-4 6.3 x 10-6 Tartaric Acid H2C4H4O6 150 g/mol 1.0 x 10-3 4.6 x 10-5 Guiding Question What is the identity of an unknown diprotic acid? Supporting Calculations. Include an annotated sample calculation showing how you determined the molar mass of the unknown diprotic acid (i.e. How did you find the equivalence point, and use that value to calculate the molar mass of the unknown acid?). Include an annotated calculation showing how you determined the Ka₁ and Kaz (i.e. How did you find Ka1 and Ka2?). Provide a percent error comparing your experimental molar mass to the accepted value. File Home Insert Page Layout Formulas Data Review View Help Cut Copy Calibri 11 AA == Wrap Text General v Paste BIU A Merge & Center $% 900 Format Painter Conditional Format as Formatting Table Clipboard 5 Font 5 Alignment Number S Styles B11 X ✓ fx 22.5 A B C D E F G H I J K L M N 1 pH 2 Moles NaOH 3 Moles Unknown Acid 4 Molarity Unknown Acid 5 Total Moles Acid 6 Molar Mass of Acid + 7 Initial NaOH (mL) 42.5 8 Initial pH 2.91 9 Volume 1st half 7.5 10 Volume 1st EP 12.5 11 Volume 2nd half 22.5 12 Volume 2nd EP 26.5 13 14 15 16 17 18 19 20 21 22 23
Your Task In this investigation you will monitor the pH of an unknown diprotic acid solution as it is titrated with a standardized sodium hydroxide solution. Using the pH curve, you will determine the molar mass and identity of the unknown acid From the following list of five diprotic acids. You should confirm the identity by comparing the pH at the half-equivalence points with the accepted pKa1 and pKa2 values. Diprotic Acid Oxalic Acid Formula H2C2O4 Molecular weight 90 g/mol Ka1 Ka2 6.0 x 10-2 6.1 x 10-5 Malonic Acid H2C3H2O4 104 g/mol 1.5 x 10-3 2.0 x 10-6 Maleic Acid H2C4H2O4 116 g/mol 1.2 x 10-2 5.9 x 10-7 Malic Acid H2C4H4O5 134 g/mol 3.5 x 10-4 6.3 x 10-6 Tartaric Acid H2C4H4O6 150 g/mol 1.0 x 10-3 4.6 x 10-5 Guiding Question What is the identity of an unknown diprotic acid? Supporting Calculations. Include an annotated sample calculation showing how you determined the molar mass of the unknown diprotic acid (i.e. How did you find the equivalence point, and use that value to calculate the molar mass of the unknown acid?). Include an annotated calculation showing how you determined the Ka₁ and Kaz (i.e. How did you find Ka1 and Ka2?). Provide a percent error comparing your experimental molar mass to the accepted value. File Home Insert Page Layout Formulas Data Review View Help Cut Copy Calibri 11 AA == Wrap Text General v Paste BIU A Merge & Center $% 900 Format Painter Conditional Format as Formatting Table Clipboard 5 Font 5 Alignment Number S Styles B11 X ✓ fx 22.5 A B C D E F G H I J K L M N 1 pH 2 Moles NaOH 3 Moles Unknown Acid 4 Molarity Unknown Acid 5 Total Moles Acid 6 Molar Mass of Acid + 7 Initial NaOH (mL) 42.5 8 Initial pH 2.91 9 Volume 1st half 7.5 10 Volume 1st EP 12.5 11 Volume 2nd half 22.5 12 Volume 2nd EP 26.5 13 14 15 16 17 18 19 20 21 22 23
Principles of Modern Chemistry
8th Edition
ISBN:9781305079113
Author:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler
Publisher:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler
Chapter15: Acid–base Equilibria
Section: Chapter Questions
Problem 57P
Related questions
Question
Use data to answer the question.
Transcribed Image Text:Your Task
In this investigation you will monitor the pH of an unknown diprotic acid solution as it is titrated with a
standardized sodium hydroxide solution. Using the pH curve, you will determine the molar mass and
identity of the unknown acid From the following list of five diprotic acids. You should confirm the
identity by comparing the pH at the half-equivalence points with the accepted pKa1 and pKa2 values.
Diprotic Acid
Oxalic Acid
Formula
H2C2O4
Molecular weight
90 g/mol
Ka1
Ka2
6.0 x 10-2
6.1 x 10-5
Malonic Acid
H2C3H2O4
104 g/mol
1.5 x 10-3
2.0 x 10-6
Maleic Acid
H2C4H2O4
116 g/mol
1.2 x 10-2
5.9 x 10-7
Malic Acid
H2C4H4O5
134 g/mol
3.5 x 10-4
6.3 x 10-6
Tartaric Acid
H2C4H4O6
150 g/mol
1.0 x 10-3
4.6 x 10-5
Guiding Question
What is the identity of an unknown diprotic acid?
Supporting Calculations.
Include an annotated sample calculation showing how you determined the molar mass of
the unknown diprotic acid (i.e. How did you find the equivalence point, and use that value
to calculate the molar mass of the unknown acid?).
Include an annotated calculation showing how you determined the Ka₁ and Kaz (i.e. How
did you find Ka1 and Ka2?).
Provide a percent error comparing your experimental molar mass to the
accepted value.
File
Home Insert
Page Layout
Formulas Data Review View
Help
Cut
Copy
Calibri
11 AA ==
Wrap Text
General
v
Paste
BIU
A
Merge & Center
$% 900
Format Painter
Conditional Format as
Formatting Table
Clipboard
5
Font
5
Alignment
Number
S
Styles
B11
X
✓
fx 22.5
A
B
C
D
E
F
G
H
I
J
K
L
M
N
1 pH
2 Moles NaOH
3 Moles Unknown Acid
4 Molarity Unknown Acid
5 Total Moles Acid
6 Molar Mass of Acid
+
7 Initial NaOH (mL)
42.5
8 Initial pH
2.91
9 Volume 1st half
7.5
10 Volume 1st EP
12.5
11 Volume 2nd half
22.5
12 Volume 2nd EP
26.5
13
14
15
16
17
18
19
20
21
22
23
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
Step by step
Solved in 2 steps
Recommended textbooks for you
Principles of Modern Chemistry
Chemistry
ISBN:
9781305079113
Author:
David W. Oxtoby, H. Pat Gillis, Laurie J. Butler
Publisher:
Cengage Learning
Chemistry
Chemistry
ISBN:
9781305957404
Author:
Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:
Cengage Learning
Chemistry: An Atoms First Approach
Chemistry
ISBN:
9781305079243
Author:
Steven S. Zumdahl, Susan A. Zumdahl
Publisher:
Cengage Learning
Principles of Modern Chemistry
Chemistry
ISBN:
9781305079113
Author:
David W. Oxtoby, H. Pat Gillis, Laurie J. Butler
Publisher:
Cengage Learning
Chemistry
Chemistry
ISBN:
9781305957404
Author:
Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:
Cengage Learning
Chemistry: An Atoms First Approach
Chemistry
ISBN:
9781305079243
Author:
Steven S. Zumdahl, Susan A. Zumdahl
Publisher:
Cengage Learning
Chemistry: The Molecular Science
Chemistry
ISBN:
9781285199047
Author:
John W. Moore, Conrad L. Stanitski
Publisher:
Cengage Learning
Chemistry: Principles and Reactions
Chemistry
ISBN:
9781305079373
Author:
William L. Masterton, Cecile N. Hurley
Publisher:
Cengage Learning