QUANTITATIVE ANALYSIS 421 tube be removed from the furnace, nor must any attempt be made to crack open the capillary end by means of a file, etc ., even when the tube is still in position. To release the pressure, first gently warm the capillary end of the Carius tube (which projects just beyond the mouth of the iron tube) with a small smoky Bunsen flame. The extreme end of the cold capillary will always contain some condensed liquid, which under the influence of this preliminary warming will be forced back into the wider portion of the tube: this step is particularly necessary in the estimation of sulphur (p. 423). Finally increase the heating of the extreme tip of the capillary until softening of the glass finally allows the compressed gases to blow out. Now remove the tube from the furnace and make a deep file-mark completely round the tube about 15 cm. from the bottom: then wash the outside of the tube to remove any powdered glass from the file-mark, and also all traces of charred paper,
This is the end of the preview. Sign up
access the rest of the document.
This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.