Assemble the Drop Dispenser
Figure 1. The complete Drop Dispenser, consisting of the syringe, two
stopcocks, and the drop tip, connected to the syringe holder.
1. Remove the plunger from the syringe. Remove the
protective white plastic caps from the stopcock valves.
2. Connect the two stopcocks together. Connect the
stopcocks to the end of the syringe.
3. Connect the drop tip to the bottom of the stopcocks.
4. Attach the Drop Dispenser (syringe, two stopcocks, and
drop tip) to the support rod using the syringe rod, as shown
in Figure 1.
Calibrating the Drop Counter
The Drop Dispenser has two stopcocks. The bottom stopcock is
used to regulate flow rate, and the top stopcock is used to turn
the flow on and off. The top stopcock should always be in either
the completely open (handle vertical) position or the completely
closed (handle vertical) position.
NOTE: If you are using PASCO standard
equipment, calibration of the sensor is rarely
required. However, if you are using third-party
equipment, it is recommended that you take the
following calibration steps.
The following two methods illustrate the calibration procedure:
Calibration using PASCO Capstone
1. Attach the Drop Dispenser to a support rod if you have not
already done so.
2. Fill the syringe with titrant. Place a beaker under the Drop
Dispenser to catch the titrant.
3. Open both stopcock valves and adjust the valve on the
bottom stopcock so that the drops fall at a rate of about 1
drop per second. Close the top valve after the rate is
achieved. Discard the titrant in the beaker as directed by
the instructor.
4. Mount the Wireless Drop Counter to the same support rod
as the Drop Dispenser, between the Dispenser and the
base.
5. Align the drop tip with the rectangular window in the
Wireless Drop Counter. Place a graduated 10 mL cylinder
under the Drop Counter window so it can catch drops from
the drop tip and give you a measure of the volume.
6. Start Capstone. Connect the Wireless Drop Counter
wirelessly to the computer with the following steps:
a. In Capstone, open the "Hardware Setup" window.
b. Turn on the Wireless Drop Counter.
c. Click the Drop Counter with the Device ID that
matches the Device ID number (XXX-XXX) printed on
your sensor.
7. In Capstone, click the "Calibration" icon in the Tools panel
to open the Calibration window. In Step 1, select the
Volume measurement and click "Next". In Step 2, the
"Wireless Drop Counter Sensor" is picked by default. In
Step 3, the default choice for type of calibration is "One
Standard (1 point slope)". Click "Next" to open Step 4.
8. Open the top stopcock valve to let the titrant begin dripping
into the cylinder. Note that Capstone will automatically
begin recording the number of drops (you do not need to
click "Record").
9. After about 5 mL of titrant is collected in the graduated
cylinder, close the top stopcock. Carefully measure the
exact volume of titrant in the graduated cylinder.
Product Guide | 012-16026B
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