American College of California Titrating Phosphoric Acid Chemistry Lab Report

  

Description

hello

i had lab and we did. 2 experiments Acid Identification from pH Titration Curves Lab Report + Titrating Phosphoric Acid Lab Report

i will be attaching the 2 experiments i did in lab and then there is 2 lab reports + 2 excel sheets (that u need to input the data in )

the first 2 documents – i have already did the pre lab and u just need to take the data from that document i collected for the pH and answer the lab report questions that are not filled in yet. + 2 excel sheets u need to input the data

for the choose item – it is choices – so i will send them once u need it

pls dont accept the bid till u know u are sure

due in 5-6 hours eastern time

Acid Identification from pH Titration Curves Lab Report
Pre-Lab
1. (0.33 points)When a strong acid is titrated with a strong base, what is the expected pH at
the equivalence point?
Choose an item.
2. (0.33 points)When a weak acid is titrated with a strong base, what is the expected pH at
the equivalence point?
Choose an item.
3. (0.34 points)When a weak base is titrated with a strong acid, what is the expected pH at
the equivalence point?
Choose an item.
Calculations and Questions
1. (1 point)Enter your data from Table 1 in a spreadsheet program and create a graph with
“Volume NaOH (mL)” on the x-axis and “pH of acid solution” on the y-axis. Include a
title with Unknown Acid # where # is the number for the acid tested. Paste a copy of
your graph below.
Click here to paste your graph
2. (1 point)Determine the pH at the equivalence point on your titration curve. This may not
necessarily correspond to a data point.
Enter the pH at the equivalence point here
Does this pH indicate that the unknown acid is Strong or Weak
Unknown Acid Enter # is a Choose an item. acid
3. (1 point)Determine the volume in mL of base required to reach the equivalence point on
your titration curve. This may not necessarily correspond to a data point.
Enter the volume at the equivalence point here mL
The 10.00 mL of unknown acid has a concentration of 0.10 M and was titrated with 0.10
M NaOH so the number of H atoms in the unknown acid should be equal to the volume
of base to reach the equivalence point divided by the volume of acid.
Unknown Acid Enter # is a Choose an item. acid
4. (1 point)Based on your answers in the previous two sections, the identity of Unknown
Acid Enter # is Choose an item.
5. (1 point)Below is a titration curve for a weak diprotic acid, H2A, titrated with NaOH.
Under the “Insert” menu, click on “TextBox” and label the points on the curve
correspond to H2A, HA- and A2- as the primary species affecting pH in solution. Label
the sections where H2A/HA- and HA-/A2- buffer solutions would exist.
0.10 M H2A Acid Titrated with 0.10 M
NaOH
pH of Acid Solution
14
12
10
8
6
4
2
0
0.00
5.00
10.00
15.00
20.00
25.00
30.00
Volume of NaOH Added (mL)
6. (1 point)Enter your data from Table 2 in a spreadsheet program and create a graph with
“Volume NaOH (mL)” on the x-axis and “pH of acid solution” on the y-axis. Include a
title with Unknown Acid # where # is the number for the acid tested. Paste a copy of
your graph below.
Click here to paste your graph
7. (1 point)Determine the pH at the equivalence point on your titration curve. This may not
necessarily correspond to a data point.
Enter the pH at the equivalence point here
Does this pH indicate that the unknown acid is Strong or Weak
Unknown Acid Enter # is a Choose an item. acid
8. (1 point)Determine the volume in mL of base required to reach the equivalence point on
your titration curve. This may not necessarily correspond to a data point.
Enter the volume at the equivalence point here mL
The 10.00 mL of unknown acid has a concentration of 0.10 M and was titrated with 0.10
M NaOH so the number of H atoms in the unknown acid should be equal to the volume
of base to reach the equivalence point divided by the volume of acid.
Unknown Acid Enter # is a Choose an item. acid
9. (1 point)Based on your answers in the previous two sections, the identity of Unknown
Acid Enter # is Choose an item.
Titrating Phosphoric Acid Lab Report
Pre-Lab
1. (0.5 points)Determine the volume of 2.0 M NaOH needed to prepare 100 mL of 0.10 M
NaOH.
Enter your answer here
2. (1.5 point)Complete the following equations for the titration of phosphoric acid with
sodium hydroxide.
H3PO4 + 1 NaOH → Enter your answer here
H3PO4 + 2 NaOH →Enter your answer here
H3PO4 + 3 NaOH →Enter your answer here
3. (0.5 points)The acid color of a certain indicator is yellow and the base color is blue.
What is the color expected at the equivalence point for this indicator?
Enter your answer here
Table 1 (1.5 points)
Phenolphthalein
Trial
Bromcresol Green
Trial
Final Volume
00.00
00.00
Initial
Volume
00.00
00.00
Volume Used
(Final–
Initial)
00.00
00.00
Part 1 Calculations and Questions
1. (0.5 points)Calculate the moles of NaOH added to the H3PO4 solution in the
Phenolphthalein Trial.
Mol of NaOH = Enter your answer here
2. (0.5 points)Calculate the moles of H3PO4 initially present in the H3PO4 solution in the
Phenolphthalein Trial
Mol of H3PO4 = Enter your answer here
3. (1 point)Divide the moles of NaOH by moles of H3PO4. This ratio is “n” in the above
chemical equation. Write the balanced equation from Pre-Lab #2 that corresponds to this
ratio.
n = Enter your answer rounded the nearest whole number
Balanced chemical equation Enter your answer here
4. (2 points) Repeat steps 1-3 above, using the data for the Bromcresol Green Trial.
Mol of NaOH = Enter your answer here
Mol of H3PO4 = Enter your answer here
n = Enter your answer rounded the nearest whole number
Balanced chemical equation Enter your answer here
5. (1 point)Based on your results, does the titration of phosphoric acid take place in a single
step or multiple steps?
Choose an item.
Part 2 Calculations and Questions
1. (2 points)Enter your data into a spreadsheet program such as Excel.
Under the “Insert” menu, click on “TextBox”. Then on your titration curve for
Phosphoric acid, label the following.
a. point on curve where H3PO4 is the main substance affecting pH
b. section on curve of H3PO4/H2PO4 buffer region
c. point on curve where H2PO4- is the main substance affecting pH
d. section on curve of H2PO4-/HPO42- buffer region
e. point on curve where HPO42- is the main substance affecting pH
f. point on curve where PO43- is the main substance affecting pH
Insert a copy of your graph below. If necessary, you may print a copy of the graph, label
it by hand and then take a picture of it.
Enter your graph here
2. (1 points)In Part 1, you used phenolphthalein as the indicator during the first titration of
phosphoric acid. According to the balance equation you selected for the phenolphthalein
titration, what substance is indicated on the titration curve from Part 2 at the point where
phenolphthalein changed color?
Choose an item.
3. (1 points)In Part 1, you used bromcresol green as the indicator during the second titration
of phosphoric acid. According to the balance equation you selected for the bromcresol
green titration, what substance is indicated on the titration curve from Part 2 at the point
where bromcresol green changed color?
Choose an item.
4. (2 points)In this experiment, you titrated H3PO4 with NaOH. When the titration was
done, all that remained was Na3PO4. What would the titration curve of 0.10 M Na3PO4
titrated with 0.10 M HCl look like? (Hint: It is related to the Part 2 curve) Draw it on the
graph in your lab manual. Take a photo of your work, include your name and date in the
photo and insert the photo below.
Enter photo of your work here
2
93
2 89
2 92
3
2 90
Z 91
3.16
2
3.51
05
3
3.09
3
58
5.20
it
3
SO
3.20
4
OO
Z
3.25
U
25
3
3.29
3 35
3.47
95
Z 95
2 97
01
S
UJ
62
12.48
27.00
12.72
28 OO
12.88
9
3 28
3 33
3 42
3 62
3
78
5
38
12.14
12
96
13.09
13.12
13.18
dB 22
13
40
13
43
44
13
13.46
13.26
13
47
13 30
13
51
61
3.32
12 76
13.35
12
13.3g
13 SO
13 52
CO.IO
2
1
5ML
OM
NA 1721004
Naz 1 POU
Naz
Green
Out
H2O
1
2h20
3h20
APINK
I
34
O
34
I
15.5
0mL
ML
15
5
3.34
3 36
3 39
3 41
3 45
U OU
4
4
39
57
10
5 54
6 29
5
6
39
7.05
7 39
7
55
8.15
8 35
8 36
9
05
9.15
CO Ol
10.09
10 19
10.31
11 05
Il 25
11 35
Il
Il
35
50
12.05
12 25
12 45
13 05
13 10
13 15
13 25

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