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Unformatted text preview: s per container, and the active ingredients. Weigh 1 dose of the antacid as per the
instructions. If the antacid is a solid, grind it using a mortar and pestle, and place the powdered
antacid into a flask. If the antacid is a liquid, measure out a dose of the antacid directly into the
flask. Whether the sample is solid or liquid, add about 100 mL of water. Work with one sample
at a time; you will want to perform three trials of each antacid you chose. Since you only have
two flasks, one lab partner can be cleaning a flask and preparing the next sample while another
lab partner is performing the titration. Each lab partner should perform approximately the same
number of titrations.
Calibration of Pasco Systems:
Most probes for the Pasco system start off basically analog voltages. We must start by
telling the system what voltages correspond to what pH levels. In so doing, we will use buffer
solutions that are at very well known (and stable) pH.
Start the computer, and the Pasco software. Choose the “pH probe” sensor. Be sure that
you select position “A” and that you have the temperature probe plugged into this port.
Dakota State University page 1 57 of 232 Experiment 14: Titration of Antacids General Chemistry I and II Lab Manual 2.
Choose “calibrate”; put some of the higher pH buffer to your small cup. Put the pH
probe into the buffer and allow a few minutes to equilibrate. Type the correct value into the
“high pH” space (for example, if it is the pH 10.00 buffer solution, type 10.00 into this space).
As soon as the reading seems to have stabilized, click “read”. Return the buffer solution into the
correct “used buffer” container.
For the low pH calibration, refill your little cup with the low pH buffer solution. Empty
out your calorimeter. Put the pH probe into the buffer and allow a few minutes to equilibrate.
Type the correct value into the “low pH” space (for example, if it is the pH 2.00 buffer solution,
type 2.00 into this space). As soon as the reading seems to have stabilized, click “read”. Return
the buffer solution into the correct “used buffer” container.
If you followed these instructions carefully, your Pasco system should be ready.
In the front of the room you will find 0.1M hydrochloric acid. Choose one bottle and
record the bottle number; this is the same acid you will use for the entire experiment, so use it
sparingly. Fill the buret (NEVER fill a buret above your head), and set up the Pasco box to
manually collect your data for you. To do so, you will want to collect data as follows;
If you have not already done so, close the calibration window by clicking OK.
Click on “sampling options”. Select “keyboard sampling”; under units put “volume of
Open “table” and “graph” by dragging the appropriate icons over the pH probe icon.
Place the pH probe into the beaker with calcium carbonate; give it a couple of minutes to
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