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CHEM 1&2 Lab Manual & worksheets pg 152

CHEM 1&2 Lab Manual & worksheets pg 152 -...

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Experiment 13: Molecular Mass of an Acid General Chemistry I and II Lab Manual Dakota State University page 152 of 232 Titration of the Acid: Measure out about 0.1 gram of the unknown acid (you do not need exactly 0.1 g, but you do need to know exactly how much you have and you must have at least 0.1 g to have as many significant figures as possible). If your lab instructor requests you to do so, add a couple of drops of phenolphthaliene. Titrate the sample either to the endpoint, or using the Pasco system to collect data as your lab instructor requests. Perform at least three titrations; if any of the runs are off by more than 0.04 mL from any other run, perform a fourth titration and discard the titration that seems to most significantly disagree with the other runs.
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Unformatted text preview: Determine the molar mass of the acid from this step. Calculations: Standardization: KHP is a monoprotic acid, so the reaction can be simplified as KHP (aq) + NaOH (aq) & KNaP (aq) + H 2 O (l) Using standard stoichiometric techniques, calculate the molarity of NaOH for each run. Take the average and determine the standard deviation. Molecular Mass: The acid is monoprotic, so again, we can write HA (aq) + NaOH (aq) & NaA (aq) + H 2 O (l) Use standard stoichiometric techniques to calculate the moles of acid for each run, then, for each run, divide the mass of the acid by the moles of the acid to determine the molecular mass. Take the average and determine the standard deviation....
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