Discuss concepts of alkalinity and buffering.
THE LAB REPORT I HAVE DONE HALF OF IT PLEASE COMPLETE THE FOLLOWING
CAN YOU DO
DATA PROBLEM 2,3,4 DON’T FORGET SAMPLE CALCULATION
DISSCUSION 1 AND 2
Requirements: FOLLOW THE FILE DISCRIPTION
Lab 1: Alkalinity and the Carbonate System
Date lab performed: September 14, 2023
Date report submitted: September 21, 2023
Group members: Fay Albannaw, Yousef Alrefaee, Caitlin Rodriguez, Caylin Radtke, Jovani Washington, Kayla Hoagland, Ibrahim Al Bulushi
Group leader: Caylin Radtke
Data Recorder: Caitlin Rodriguez
Course code and title: ENV 4004L
Section: 004
Lab 1: Alkalinity and the Carbonate System
Objectives
Perform titrations.
Discuss concepts of alkalinity and buffering.
Measure alkalinity of water samples
Estimate the concentration of Total Inorganic Carbon (i.e., sum of carbonate system species) from alkalinity measurements.
Background
Alkalinity quantifies the ability of water to resist the effects of added acid; that is, alkalinity
counters added acid to prevent the pH from dropping (to some degree). Thus alkalinity is
sometimes called acid neutralizing capacity. The importance of the alkalinity of natural waters
received considerable attention when the negative effects of acid rain were observed in the 1960s
and 1970s.
For typical natural waters, the carbonate system is the predominant source of alkalinity, although
the presence of other weak acids (and weak bases) can also contribute. For example, as water
seeps through the soil and contacts rocks and minerals, it picks up humic acids, borate, silicic
acid, and hydrolyzed metal ions that contribute to alkalinity. In some stages of sewage
processing, the presence of organic acids and ammonia from microbial activity contributes to the
alkalinity of wastewater. The theory and experiments presented in this lab focus on the main
source of alkalinity, the carbonate system (carbonate and bicarbonate ions, carbonic acid and
dissolved carbon dioxide).
Procedures
There are 3 samples to be analyzed: lab tap water, your team sample (this should be a sample collected by your team; you should have been given instructions to bring a sample to class), and
Solution A (provided by the TA). For each sample you will titrate using indicators, then repeat
using the pH meter to display the pH directly. In your lab report you will be asked to compare
the ease and reliability of the two methods. You will run an additional titration on Solution A to
prepare a titration curve.
1. Calibrate electrode using pH buffer solutions and instructions provided.
2. Rinse buret with sulfuric acid and fill using the funnel. Record the concentration of titrant
as indicated on the bottles provided: __________. (You will need this for your data analysis.)
3. Titration procedure for each sample using indicators:
a. Place 50 mL of sample in a clean beaker. Add magnetic stir bar and place on magnetic stirrer to mix. Measure the initial pH with the pH meter and record the value in Table 2. Remove the pH meter probe.
b. Add 5 drops phenolphthalein indicator. Record starting position of the titrant.
c. (If the solution is already colorless, Vp is zero and you can proceed to the next step.) Carefully add titrant until the mixture with phenolphthalein becomes colorless. Record the ending position of titrant and calculate the volume of titrant (Vp) added to reach this endpoint. Record the pH which should be about 8.3. Remove the pH meter probe.
d. Add 5 drops methyl orange indicator. Record the new starting position of titrant in the buret.
e. At first the color should be yellow; carefully add titrant until the mixture becomes orange, then record the ending position of titrant and calculate the volume of titrant (Vmo) added to reach this endpoint. Record the pH which should be about 4.5.
4. Refill buret with sulfuric acid titrant using the funnel as necessary.
5. Titration procedure for each sample using pH meter:
a. Place 50 mL of sample in a clean beaker. Add magnetic stir bar and place on magnetic stirrer to mix. Measure the initial pH with the pH meter and record the value in Table 3. Record starting position of titrant.
b. Carefully add titrant until the mixture pH is just below the target 8.3; record the actual ending pH, and record the volume of titrant (Vp) added to reach this endpoint.
c. Record the new starting position of titrant. Titrate carefully until the mixture pH is just below the target 4.5; record the actual ending pH, and record the volume of titrant (Vmo) added to reach this endpoint.
6. Repeat steps 3 through 5 for remaining water samples to be analyzed.
Results
Measurements:
Table 1: Alkalinity titration data collected in lab using indicators
Table 2: Alkalinity titration data collected in lab using pH meter
Table 3: Titration curve procedure for solution A
Data Processed:
Tap Water:
ALKTotal =
Carbonate Alkalinity = 0
Hydroxide Alkalinity = 0
Home Water:
ALKTotal =
Carbonate Alkalinity =
Hydroxide Alkalinity = 0
Solution A:
ALKTotal =
Carbonate Alkalinity =
Hydroxide Alkalinity =
Sample calculations:
Discussion
References
Davis, M.L., & Cornwell, D.A. (2008). Introduction to environmental engineering. Dubuque,
IA: McGraw-Hill Companies.
Davis, M.L., & Masten, S.J. (2004). Principles of environmental engineering and science. New
York, NY: McGraw-Hill, pp. 64-73.
Sawyer, C.N., McCarty, P.L., & Parkin, G.F. (2003). Chemistry for environmental engineering
and science. Boston: McGraw-Hill.
U.S. Environmental Protection Agency. (n.d.). Effects of Acid Rain – Surface Waters and Aquatic Animals. Retrieved from .
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