Sample not dry
If a sample has not been thoroughly dried, the mass displayed
by the balance will be the mass of the substance plus the mass
of any liquid on it.
If the sample is a product of a reaction, one indication that
it may be wet is if the percent yield of the reaction is greater
than one hundred.
Another sign of a wet sample is that the mass displayed on
the balance gradually falls. This happens because the liquid is
Solids collected by suction filtration are often moist. After
suction filtration, to further dry the sample, place it on a large
piece of filter paper. Crush the sample with another piece of
filter paper using your thumb (be sure to wear gloves if the liquid
is hazardous), and allow the sample to dry in the air for several
minutes before remeasuring its mass.
Video: Wet samples ( 5.72 M )
Copyright © 1995-1996 NT Curriculum Project, UW-Madison