That drop can be transferred to the titrand by touching the drop against the

That drop can be transferred to the titrand by

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That drop can be transferred to the titrand by touching the drop against the side of the flask or raising the Erlenmeyer flask so the solution inside and the drop barely touch. Once a slight pink shade in the titrand has been achieved through several repetitions of careful and small drops, the final buret reading should be subtracted by the initial buret reading to get the amount of titrant used, in milliliters. Convert the amount of titrant used from milliliters to liters. Solve for the moles of HCl by using the molarity formula and plugging in 0.500 as the molarity and the amount of titrant used, in liters, as the liters. Convert the computed amount of moles of HCl to moles of sodium hydroxide using the chemical equation and stoichiometry. Lastly, divide the computed amount of moles of sodium hydroxide by the amount of 0.005L (5mL) to get the molarity of the sodium hydroxide. CONCLUSION: From the acid-base titration, we were able to find the molarity of the unknown concentration of HCl. SOURCES OF ERROR:
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There were many sources of error in our experiment. For example, while the metal stirrer and stir plate were in use, some of the titrand splashed up onto the walls of the Erlenmeyer flask. This tampered with the accuracy of the reaction, for the NaOH was not being dropped into the entire volume of HCl. Additionally, because a light shade of pink will ensure the most accurate standardization reading, the fact that we ended up with deeper shades of pink could have been another source of error. A lot of the time, we arrived at a faint pink shade, however adding a single drop turned this dull color to a vibrant one. Aside from experimental errors, we could have encountered analytical errors, such as reading the initial and final buret reading incorrectly. We might have not read it at eye level or had a measurement that was in between the indicated the volume markings. RECOMMENDATIONS: For anyone who wishes to redo the lab, I would recommend to be very careful with the magnetic stirrer and stir plate by placing it at a low setting initially. Sometimes, the flask was moved or the setting was turned to high, which resulted in the titrand splashing up to the sides of the flask, making the experiment inaccurate. Another recommendation is to have varying and reasonable (not too big or small) quantities of HCl so there is more diversity and accuracy. Lastly, I would recommend to apply the “half drop method,” where the stopcock will be turned to a point where a small drop collects at the tip and is deposited into the titrand by pushing the drop against the edge of the flask or carefully meeting the titrand to the drop, when the solution begins to become streaky with pink. REFERENCES: The Editors of Encyclopædia Britannica. “Burette.” Encyclopædia Britannica , Encyclopædia Britannica, Inc., 4 Oct. 2013, . Libretexts. “Indicators.” Chemistry LibreTexts , Libretexts, 9 Feb. 2017, chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Acids_and_Bases/Acid/Indicator s. “Definition of Endpoint Titration.” Sciencing , sciencing.com/definition-endpoint-titration-5172167.html.
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  • Winter '20
  • mol HCl

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