PIPETS and PIPETTING
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In this experiment you will need to measure very accurately three different materials:
  1. KHP..... you will use an Analytical Balance.
  2. NaOH Solution.... you will use a Buret
  3. Vinegar.... you will use a Pipet.

You have used a pipet before.
In the
Density experiment you measured out and weighed exactly 10.00 mL of you liquid UNKNOWN to determine its density.
In the
Solvay process, you measured out exactly 5.00 mL of Sodium Bicarbonate solution and then precipitated any Chloride impurity as Silver Chloride. The cloudiness of the resulting solution was measured using the spectrometer.

5 mL PIPETS

Pictured on the left are the two 5 mL pipets in your locker.
On the left is a
Graduated Pipet and on the right is a Volumetric Pipet.
Both can measure out 5.00 mL of solution.

The Volumetric Pipet is filled to the mark and allowed to empty to deliver 5.00 mL.

HOWEVER.... the Graduated Pipet must be filled to 0.0 mark and then emptied only to the 5.0 mark. The very botton of this pipet is not calibrated so this liquid must remain in the pipet!

Also note the construction of all accurate volumetric equipment. There is always a narrow part and this is where the volume is actually measured. This part of the glassware is narrow so if you make a small error in adjusting the meniscus to that mark, the actual volume error will still be small.
HOWEVER this should not be an invitation to be sloppy!

  RWK  6/8/98