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Smith Section 019 Lab 5: Acid-Base Titration: Determination of the Concentration of NaOH Solution March 7, 2018 CHEM 102 Section TA: Lab Partner:

Smith Section 019 Abstract The purpose of this experiment was to determine the concentration of an unknown solution of NaOH an acid-based titration. The mass and volume of oxalic acid along with volume of NaOH solution were measured to calculate the molarity. Titration is mainly done to determine the quantity or concentration of one of the reagents, when the other solution already being known. Two trials of titration using oxalic acid and sodium hydroxide were done. The calculated moles for the oxalic acid solution in trial I and II were 0.003819 moles and 0.0038 moles. The calculated moles for the sodium hydroxide solution in trial I and II were 0.007638 moles and 0.0076 moles. In this experiment, using the molarity equation of M =

moles , the molarity of sodium hydroxide was determined to be .457 moles/liter, making it higher volume than the molarity of oxalic acid, reading in at .19 moles/liter. Introduction Titration is a process used to determine the quantity of one substance by adding a measured amount of a second substance. 1 By gradually adding a solution of a known concentration to a second solution, one is capable of determining the exact concentration of the acid or base. Solutions of a known concentration is referred to a standard solution. The end point in traditional titrimetry is more often than not indicated by some substances added into the analyte solution, which change color right away after the equivalence point has been attained.2 Known as an “indicator” this is used to help show when the titration has reached the point of neutralization. Phenolphthalein is the colorless indicator that was placed in the solutions during this experiment that changes colors when the end point has been reached to show the end of the titration. In acid-base titration, an indicator is used to determine the end point of the titration at which the acid and base are in the exact proportions necessary to form salt and water only. 2 The titration technique will be used to indicate the concentration levels of an oxalic acid solution and a sodium hydroxide solution by calculating the data to compare the final molarity results, showing which solution has a higher concentration.

Smith Section 019

Procedure A standard oxalic solution was created. Mass of oxalic acid between 2.2 and 2.5 g was weighed out on weighing paper and recorded into data. Placed the oxalic acid into a 100-mL volumetric flask that was filled half way with deionized water and swiveled the flask until the oxalic acid had fully dissolved. Next, added more deionized water to the flask to bring the solution up to the etched line on the flask. Placed a stopper on flask and shook. Molarity of the acid was calculated. Cleaned burets with deionized water. Set up two burets and rinsed twice with 5 to 10 mL of NaOH solution in one and oxalic acid in the other. Filled each buret with separate solution to above the zero mark. Brought solution to at zero or below zero, released any air bubbles and that initial volume was recorded. Rinsed a 250-mL Erlenmeyer flask several times with deionized water and set up beneath the burets. Added about 20 mL of oxalic acid solution into the flask from the buret and record volume. Added two drops of phenolphthalein indicator into the flask and stirred very gently. Next, Sodium Hydroxide solution was added into the flask until we saw pink. One the pink landing in the solution was not dissolving and turned the solution completely pink, it had reached its end point. The volume of the NaOH left in the buret was calculated. Trial I and II was executed and completed by doing each of the steps listed above and all data was recorded. Results Moles of oxalic acid and sodium hydroxide for trial 1 and trial 2 are summarized in Table 1. Trial I

Trial II

Moles of Oxalic Acid

0.003819 moles

0.0038 moles

Moles of Sodium Hydroxide

0.007638 moles

0.0076 moles

Table 1. Moles data

Smith Section 019 In table 1, the moles of oxalic acid transferred to the Erlenmeyer flask for trial I was calculated to be 0.003819 and for trial II to be 0.0038. The moles of sodium hydroxide calculated from moles of oxalic acid for trial I was 0.007638 and trial II was 0.0076. The moles were calculated as:

M x L=moles

.19M x .201L = .003819 moles .19M x .020L = 0.0038 moles Molarity of oxalic acid and sodium hydroxide calculated in Table 2.

Molarity Table 2. Molarity Data

Oxalic Acid .19 moles/liter

Sodium Hydroxide .475 moles/liter

In table 2, the final molarity for each solution: Oxalic Acid and Sodium Hydroxide are calculated at .19

moles/L and .475 moles/L. The molarities was calculated as:

molarity=M =

moles of solute liters of solution

Discussion Errors during this experiment that could have effects the final results were an end point error. Sometimes during titration experiments, the indicator does not fully change color instantly, even if the reaction has stopped which could have affected our final volume measurements. Incorrect measurements by misreading the volume could easily alter final results and calculations. This can be done by simply reading the volume at the wrong angle which can possibly affect the correct volume measurement. To improve for future experiments, keeping a closer eye on the experiments to perfectly calculate when a reaction is happening and has finished, along with carefully reading measurements to have accurate and correct data is crucial. Since molarity is calculated to present the concentration levels, .475 moles/liter of NaOH is significantly higher than .19 moles/liters of oxalic acid, showing that sodium hydroxide has a higher concentration. Conclusion

Smith Section 019 The average molarity of sodium hydroxide for both trials was .475 M which is higher than the molarity of oxalic acid solution being .19 M. This concludes that sodium hydroxide had a higher concentration. References 1. Reger, D., Goode, S., Ball, D., & Taylor-Perry, A., (2016) Acid Base Titration: Determining the Concentration of a NaOH Solution, QDE Press Inc,. Montgomery, AL, 257-260. 2. Okoduwa, S. I. R., Mbora, L. O., Adu, M. E., & Adeyi, A. A. (2015). Comparative Analysis of the Properties of Acid-Base Indicator of Rose (Rosa setigera), Allamanda (Allamanda cathartica), and Hibiscus (Hibiscus rosa-sinensis) Flowers. Biochemistry Research International, 2015, 381721. http://doi.org/10.1155/2015/381721

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University of South Carolina Honor Code It is the responsibility of every student at the University of South Carolina Columbia to adhere steadfastly to truthfulness and to avoid dishonesty, fraud, or deceit of any type in connection with any academic program. Any student who violates this Honor Code or who knowingly assists another to violate this Honor Code shall be subject to discipline. The Law School and Medical School have a long-standing history of high academic integrity standards grounded in the ethical obligations of their professions. As such, the Medical School and Law School may adopt procedural rules different from procedures set forth in this current code, but should still report any results to the Office of Academic Integrity. Types of Honor Code Violations It is the responsibility of every student at USC to adhere steadfastly to truthfulness and to avoid dishonesty, fraud, or deceit of any type in connection with any academic program. The following examples illustrate conduct that violates the Honor Code, but this list is not intended to be an exhaustive compilation of conduct prohibited by the Honor Code. 1. Giving or receiving unauthorized assistance, or attempting to give or receive such assistance, in connection with the performance of any academic work. Examples: cheating on tests, helping someone to cheat on a test, working on an assignment or homework with someone when it is not permitted, etc. 2. Unauthorized use of materials or information of any type or the unauthorized use of any electronic or mechanical device in connection with the completion of any academic work. Examples: cheat sheets during tests, using a cell phone during a test to get answers, use of a calculator during a test when not permitted, etc. 3. Access to the contents of any test or examination or the purchase, sale, or theft of any test or examination prior to its administration. Examples: disclosing the content of a test to a friend who is in another section and taking the test after you, stealing a test before it is given, etc. 4. Unauthorized use of another person’s work without proper acknowledgment of source. Examples: This is plagiarism. This includes copying and pasting information as if it were your own work, not citing quotes or materials, poor paraphrasing, not citing after paraphrasing, utilizing another student’s paper and turning it in as your own, etc. 5. Intentional misrepresentation by word or action of any situation of fact, or intentional omission of material fact, so as to mislead any person in connection with any academic work (including, without limitation, the scheduling, completion, performance, or submission of any such work). Examples: This is lying and can include signing someone in on the attendance sheet for a class (or asking someone to sign in for you), taking a test or quiz for someone, lying about why you missed class or need to make up a test or need an extension on an assignment, etc.

Smith Section 019 6. Offering or giving any favor or thing of value for the purpose of influencing improperly a grade or other evaluation of a student in an academic program. Examples: Offering someone money for a better grade in the class, on a project, etc. 7. Conduct intended to interfere with an instructor’s ability to evaluate accurately a student’s competency or performance in an academic program. Types Of Sanctions If it is found that a student violated the Honor Code, one or more of the following sanctions will be imposed: 1. Expulsion from the University. 2. Suspension from the University for a period of no less than one semester. 3. Probation. A period of review and observation during which a student is under an official notice that subsequent violations of the Honor Code are likely to result in a more severe sanction including suspension or expulsion from the University. 4. Written Warning (first offense only). An official reprimand that makes the misconduct a matter of record in University files. Any further misconduct could result in further disciplinary action. 5. “X” on the transcript before a grade denoting an Honor Code Violation. 6. Academic Integrity Workshop. 7. Research Project. This sanction typically should be assigned for the educational benefit of the student and should be related to academic integrity or ethics on the whole or in the discipline in which the offense occurred. They will be monitored by the Office of Academic Integrity. 8. A combination of the above sanctions. Tips To Avoid Academic Dishonesty These are just a few of the ways you can avoid academic dishonesty. 

Check each course syllabus for information regarding academic dishonesty. Faculty members may have additional information beyond the University's standards. If you cannot find a written section in the syllabus, ask the faculty member what his/her expectations are.

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Attend class - you won't feel as stressed (and like you need to cheat) if you attend class and regularly review the material.

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Do not look around while taking an exam - if you don't look around you reduce the risk of someone thinking that you were looking at their exam.

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Do not give your assignments (old or new) to other students - once you hand over your assignment you don't know if the person will use it as a guide or just turn your work in as their own. This includes emailing your work to others.

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Cite your sources appropriately - it is important that you give credit to whomever’s idea you are using.

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Protect your computer login identifications and passwords. Other students could use them to access your work and subsequently implicate you in a cheating case.

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Keep your student identification card in your possession or secured. Never loan your identification to anyone.

Smith Section 019 

Don’t sign someone in for class attendance or ask someone to sign you in – that violates the Honor Code!

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Talk with your instructor - ask questions about what your professor expects on assignments, exams and group work.

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Manage your time - plan study time so you avoid last minute cramming and the temptation to cheat. Don't procrastinate!

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Make use of your free University Resources like the Writing Center, the Student Success Center, ACE. They help hundreds of students every semester be academically successful!

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Refuse to assist students who cheat.

Department of Chemistry and Biochemistry Academic Integrity Statement: You are expected to practice the highest possible standards of academic integrity. Any deviation from this expectation will result in a minimum academic penalty of your failing the assignment, and will result in additional disciplinary measures including referring you to the Office of Academic Integrity. Violations of the University's Honor Code include, but are not limited to improper citation of sources, using another student’s work, and any other form of academic misrepresentation. For more information, please see the Honor Code. The area of greatest potential risk for inadvertent academic dishonesty is plagiarism. Students should also read closely the discussion of avoiding plagiarism in the following link. http://www.plagiarism.org/plagiarism-101/what-is-plagiarism/ Remember that the first tenet of the Carolinian Creed is, “I will practice personal and academic integrity.” As a Carolinian, I certify that I neither received nor gave any outside assistance in the completion of this exam. I understand that should it be determined that I used any unauthorized assistance or otherwise violate the University's Honor Code I will receive an academic penalty and be referred to the Office of Academic Integrity for additional disciplinary action. Seehttp://www.sc.edu/academicintegrity for more information.

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