PASCO PS-2147 High Resolution pH-ORP-ISE Amplifier - Manual (Page 2)

DataStudio/DS Lite Tasks: Procedure:
Open the Setup window: On the main toolbar, click the Setup button.
Change measurements: In the Setup window, go to the ISE Sensor box
and click to place a check in the box(es) next to
the desired measurement(s).
Change the sample rate: In the ISE Sensor box, click on the down-arrow
next to the sample rate and select a new unit. Use
the Plus and Minus buttons to increase/decrease
the rate.
Measure the temp. change: Click on the Smart Tool and drag the cross hairs
to a data point. When the delta appears, click and
drag to measure the change.
Equipment required: PS-2147 High Resolution pH/ORP/ISE Sensor, pH electrode, Fast
Response Temperature Probe, DataStudio software (ver. 1.8.5 or later), ring stand, clamp for
pH probe, stirring machine, stir bar, calorimeter (part no. 650-02976 or two styrofoam cups
stacked together), 1 mL pipette, citric acid powder, balance to measure +/- 0.01 g, 100 mL
graduated cylinder, deionized water. (Optional): vinegar solution for stable pH, 0.1 M NaOH
solution
Procedure:
1. Set out chemicals a few hours before the experiment to allows the chemicals time to
equilibrate to room temperature.
2a. Add 100 mL of deionized water to the calorimeter and stir until the temperature is stable.
(Note: Without buffer, the pH is not stable or predictable. See the step 2b option.)
OR
2b. Prepare 0.6 mM acetic acid by adding 0.5 mL vinegar to 1.00 L of deionized water and
adjusting to pH 7.0 with drops of 0.1 M NaOH. Add 100 mL of this 0.6 mM acetic acid to
the calorimeter and stir until the temperature is stable.
3. Place the temperature probe and pH probe into the solution. In DataStudio’s Experiment
menu, select “Monitor data.” Stir until the solution comes to a steady temperature.
4. Weigh 10 millimoles (about 1.9 g) of citric acid powder.
5. When the temperature is steady, stop the monitoring run by pressing the Stop button.
6. Click the Start button and wait one minute to establish a baseline. Then add the citric
acid powder to the stirring solution.
7. After about two minutes, the temperature and pH should become level, and you can stop
the experiment.
8. (Optional): To find the amount of heat absorbed by the calorimeter, stir bar, and pH
electrode, repeat steps 1-5. In place of step 6, add a fixed volume of water that is slightly
cooled; follow the cooling curve after mixing the known amount of cool water. Combining
this information with the above data can allow a description of the heat absorbed per mole
citrate.
9. (Optional): Use the DataStudio calculator to convert pH to [H + ]. Use a graph display to
show the temperature change per mole of acid dissolved.
CARD 1B Enthalpy of Neutralization with pH Measurement
Activity: Enthalpy of Neutralization
with pH Measurement