Drop Counter Calibration

Use the procedure below to calibrate drops so that a precise volume of titrant is recorded in units of milliliters.

Calibrating Your Drop Counter

1. After the Drop Counter has been set up, choose Calibrate > DIG 1: Drop Counter from the Experiment menu.
2. Select Automatic.
3. Place a 10 mL graduated cylinder directly below the slot on the Drop Counter, lining it up with the tip of the reagent reservoir.
4. Open the bottom valve on the reagent reservoir (vertical). Keep the top valve closed (horizontal).
5. Slowly open the top valve of the reagent reservoir so that drops are released at a slow rate (~1 drop every two seconds). You should see the drops being counted on the computer screen.
6. When the volume of titrant in the graduated cylinder is between 9 and 10 mL, close the bottom valve of the reagent reservoir.
7. Enter the precise volume of titrant (read to the nearest 0.1 mL) in the edit box. You may want to record the number of Drops/mL displayed on the screen for possible future use.
8. Click OK. Discard the titrant in the graduated cylinder as indicated by your instructor and set the graduated cylinder aside.