2 what are we measuring with the pasco system dakota

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Unformatted text preview: pe “0” in for the volume added; click “read” to read the initial pH. (6) Add 1 to 3 drops of hydrochloric acid and give the solution a couple of minutes to equilibrate (using the pH probe to carefully stir the solution will help). Read the volume of the buret and input this for the “volume added” and click “read”. (7) Continue in this procedure, adding one to three drops at a time (8) Write the data points in your notebook. Do not count on being able to save these tables as they may be accidentally erased. (9) As soon as your data collection and transcription is completed, repeat the experiment with a new table and graph for the next sample. Calculations: On a graph of pH versus volume of acid, you will notice a rapid drop in pH at some point of the curve. At this point, all of the antacid is gone (it is called the equivalence point). Use this as the neutralization volume of the antacid. Divide the cost of the antacid by this volume to get cost per mL. Dakota State University page 1 58 of 232 Experiment 14: Titration of Antacids General Chemistry I and II Lab Manual Observations: Initial information: Antacid Brand Form Dosage Cost Cost/Dose Observations : Titration Brand Volume run 1 Volume run 2 Volume run 3 Average volume Cost/volume Observations: Dakota State University page 1 59 of 232 Experiment 14: Titration of Antacids General Chemistry I and II Lab Manual Pre-Lab Questions: 1. What is the approximate concentration of stomach acid? 2. What are we measuring with the Pasco system? Dakota State University page 1 60 of 232 Experiment 14: Titration of Antacids General Chemistry I and II Lab Manual Post-Lab Question: 1. Look at the graphs you’ve generated; where is the “endpoint” (that point where you run out of antacid” indicated? 2. Measure the volume of acid neutralized for each run, and find the average volume for each antacid. 3. Calculate the volume of acid neutralized per gram of antacid, the volume of acid neutralized per dose of antacid, and $/mL of acid neutralized. Dakota State University page 1 61 of 232 Experiment 15: Titration of Vinegar General Chemistry I and II Lab Manual Experiment 15: Titration of Vinegar Purpose: To determine the concentration of acetic acid in vinegar Purrrr-fect: Something Cat-woman used to say just before doing something villainous Background: See “Using the Pasco System” and “Basic Laboratory Procedures”; pipettes, burets, balance Introduction: Commercial vinegar is typically about 5% acetic acid (CH3 COOH). This is a classic titration in which we will determine the exact concentration of acetic acid in storebought vinegar. Procedure: You will want to set up the Pasco system for manual data collection using the pH probe. You will want to have it plot pH as a function of volume of base added. Set up a buret (see general procedures) for a titration. Standardization of the Base: Follow this procedure IF the base solution provided has not already been standardized. If the base has been standardized for you, write down the exact...
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