How to use a Crucible?

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How to use a Crucible?

• By Anthoney Tetreault

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Using the Crucible

• Hold small amounts of chemicals
• Heating at high temperatures
• The lid covers the bowl so nothing escapes
• Keep oxygen out of the reaction

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Techniques for using Crucibles

• The cover can be tilted slightly to let hot gases
  escape easily
• The crucible should be heated slowly
• With the Bunsen burner held at a distance at
  first
• Then brought in closer as the crucible gets
  warmer
• The crucible can be heated until it is red hot
• Bunsen burner is centered underneath the crucible
• The flame is turned up high and comes in contact
  with the bottom of the crucible

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Techniques for using Crucibles Cont.

• Place hot crucible on wire gauze
• A cold surface may crack the crucible
• It will ruin your experiment
• Dirt, and paint, are easily fused onto the hot
  porcelain, changing its mass.

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About Crucible

• Crucibles are very hot when you first put them on
  the wire
• Let them cool down to room temperature before
  weighing
• See if it is safe to weigh by bringing your hand
  over the crucible
• Feel for the heat to rise at first
• The crucible will be cool enough when you can let
  your hand barely touch the lid

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Cleaning a Crucible

• Step 1
• GENTLY SCRAPE RESIDUE LEFT THE MATERIALS USED IN
  YOUR EXPERIMENT FROM THE CRUCIBLE
• Step 2
• FILL YOUR PORCELAIN CRUCIBLE WITH POTASSIUM
  BICARBONATE YOU SHOULD HAVE ENOUGH BICARBONATE
  IN THE CRUCIBLE TO FILL PAST THE LINE OF THE
  REMAINING MATERIAL FROM YOUR EXPERIMENTS

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Cleaning a Crucible

• Step 3
• PLACE CRUCIBLE ON A BURNER. HEAT THE CRUCIBLE
  UNTIL THE BICARBONATE MELTS. HEAT IT UNTIL A
  LAYER OF RED POTASSIUM SALT APPEARS ON THE
  SURFACE. USING A MIXING ROD, STIR THE MELT A FEW
  TIMES. THE ENTIRE MELTING PROCEDURE SHOULD TAKE
  ABOUT ONE MINUTE.
• Step 4
• REMOVE YOUR CRUCIBLE FROM THE FLAME. POUR OUT
  THE MELT.
• Step 5
• RINSE THE CRUCIBLE IN HOT WATER. FOR PORCELAIN
  CRUCIBLES, USE A CLEAN CLOTH TO DRY THE SURFACE.

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Works Cited

• http//www.files.chem.vt.edu/RVGS/ACT/lab/Experime
  nts/crucible.html
• http//www.ehow.com/how_5045728_clean-crucibles.ht
  ml
• http//wiki.answers.com/Q/What_is_a_crucible_and_h
  ow_is_it_used_in_a_laboratory