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H-7
Then, proceed to add the base dropwise for the rest of the titration until the indicator changes color
on one drop of titrant. In these last two or three titrations try to obtain values for the molar mass
of the unknown acid that agree within one or two percent. If your results are good (
for each run are less than 0.001 of each other are consider good results), two titrations with the
correct indicator should be sufficient. If not, you may wish to do a third titration. It is important
to work quickly, but accurately. If you do not, you may not be allowed to finish all the titrations
you need to perform.
Before leaving the laboratory, check to make sure that all of your equipment is clean and back in
your drawer. It is important that the pH electrode has been washed and is stored in storage buffer
of pH 4.
When you have finished all of your titrations, and have disposed of all of the wastes properly,
wash your burets with hot
tap water (four times) and rinse once with deionized water. Leave
them at your work station filled with deionized water.
