2007-07-25 08:18:24 · 3 answers · asked by Drogba 2 in Science & Mathematics ➔ Chemistry
The previous answerer is right. Rinse with deionized water after washing. But then dry for an hour or more in a 200C oven. Cool in a dessicator. Then it is ready for the first weighing to determine the tare.
2007-07-25 08:23:39 · answer #1 · answered by steve_geo1 7 · 1⤊ 0⤋
Porcelain crucibles are hygroscopic, i. e. they absorb a bit of weighable moisture from the air. For this reason, the porcelain crucible and lid is also pre-fired (pre-heating to high temperature) to constant mass before the pre-weighing. This determines the mass of the completely dry crucible and lid. At least two firings, coolings, and weighings resulting in exactly the same mass are needed to confirm constant (completely dry) mass of the crucible and lid.
ref: http://en.wikipedia.org/wiki/Crucible
2007-07-25 08:29:19 · answer #2 · answered by Dr Dave P 7 · 0⤊ 0⤋
Wash with DI water?
2007-07-25 08:21:07 · answer #3 · answered by Anonymous · 0⤊ 0⤋