Titration Lab Report

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School

Johns Hopkins University *

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Course

EN.030.206

Subject

Chemistry

Date

Apr 3, 2024

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pdf

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5

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Selene Barajas Period 1 Question: What is the concentration of acetic acid in each sample of vinegar? Pre-Lab questions: 1) NaOH is added to HCl until the color changes at a pH of 7.5. It is found that the moles of acid equals the moles of base at a pH of 7. a. What is the titrant and analyte? The titrant is the unknown concentration of chemicals. The analyte is a chemical of known concentration that’s added to the titrant. b. What is the endpoint for the reaction? The endpoint is when there is a color change as a result of the indicator added to the solution which creates a color change based on the pH of the solution. c. What is the equivalent point The equivalence point is when the moles of the titrant are equal to the moles of the analyte. 2) Explain how rinsing the reservoir with water instead of the titrant before starting the investigation will affect the calculated unknown molarity of the titrate. (Look in procedure for answer) By rinsing the reservoir with water instead of the titrant before starting the investigation will alter the titrant concentration and result in inaccurate calculations. 3. Explain why there is a steep slope in a section of the titration curve and explain how it can be used in calculations. There is a steep slope in a section of the titrant curve because it shows the lowest concentration, slowing down the reaction which results in a steep slope in the center of the curve. 4. What types of data need to be collected to perform molarity calculations of the unknown? The types of data needed to perform molarity calculations of the unknown are the molarities and volumes of the obscure corrosion. Also, necessary to have the initial and final volumes of the equivalence point. 5. Why do you think it is important to know the exact concentration of acetic acid in apple cider vinegar? I think it is important to know the exact concentration of acetic acid in vinegar to be able to calculate additional molarity.
3) Procedure 1) calibrate the drop counter in order to get the volume of the titrant 2) rinse the 10 mL cylinder, then place the drop counting onto it. 3) We then need to add 10 mL of distilled water to the reservoir. 4 4) We then open the valve in order to record the drops that are falling. 5 5) We then need to record the volume of the water and the number of drops. 6 6) We then need to create our NaOH solution. 4) Materials Materials needed are a Labquest, Vernier Drop Counter, Vernier pH Sensor, Distilled water, Ring stand, 0.03 M NaOH solution, reagent reservoir, Magnetic stirrer and bar, Utility clamp, Unknown HCl Unknown acetic acid, beaker, Buret clamp, 3 beakers, 2 graduated cylinders, a pipet, and two types of vinegar. 5) Safety Concerns Some safety concerns are acids touching and damaging the skin, eyes, and other important body parts. Therefore, it is important to wear our safety goggles when doing the lab. NaOH is also poisonous if consumed, so it's recommended that we take these extra steps to help in our safety. 6) What data are you looking for? The data we are looking for is the amount of acetic acid in the apple cider vinegar and the HCI solution. 7) Data Table Burette Data HCI Trials Initial NaOH volume Final NaOH volume Volume of NaOH added Moles of HCI HCI pH at equivalen ce point 1 30 mL 28 mL 2 mL 0.002 0.080 M 7.89 pH 2 25 mL 21 mL 4 mL 0.0004 0.080 M 8.05 pH 8) Calculations 9) Titration curve picture for each expt.
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