I conducted an experiment, 2 lots of 25ml of water was Pipetted and added into a Burette. The resultant volume isn’t 50ml, but 49.5 why?
- Trevor HLv 71 year ago
I have never trusted a 50mL burette to deliver exactly 50.00 mL of solution when allowed to drain fully. It is not designed to do this. Therefore I would not expect a 50mL burette to read exactly 0.00mL when the empty burette is filled with 2 x 25 mL of water from a pipette. There are techniques in using a pipette that I think cannot be rigidly adhered to when using the pipette to fill a burette - such as allowing the pipette to discharge at 45° to the horizontal and then touching the pipette tip briefly onto the surface of the discharged liquid. How you would do this ( especially with the 1st 25mL) I do not know. I suggest that you repeat the (interesting) experiment by filling the burette to exactly the 25mL mark . Then add 25mL from a pipette , if possible in accordance with the " best practice" techniques of using such equipment . Then see what you get. Hopefully the burette will read 0.00mL.
- Anonymous1 year ago
Some of the water must have vaporated.
- YYYZZ 2Lv 71 year ago
Some of the water is still in the pipettes. (adhering to the sides).
- pisgahchemistLv 71 year ago
Mixing water .....
The volumes of some liquids are not additive, but that's not the case for two quantities of otherwise, pure water. You might wonder about the calibration of the buret vs the pipette, or you could have missed the park on the pipette, and just need to work on your technique.