Physics and chemistry of mining and mine ventilation; a practical handbook for vocational schools, and for those qualifying for mine foreman and mine inspector certificates - Tapa blanda

Sinopsis

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1918 Excerpt: ...tube and the rubber connection of any pure air they might have contained. The stopcock i is again opened and the leveling bottle lowered to the lowest division on the burette. The stopcock i is then closed and the gas in the burette is measured at atmospheric pressure by holding the leveling bottle in such a position that the surface of the water in the bottle is on line with the water in the burette. About two minutes is allowed for drainage of water down the sides of the burette before the measurement is taken, in order to guard against a small error which would otherwise ensue. After measurement the sample is passed into pipette a several times by raising and lowering the level bottle; this operation removes the carbon dioxide, the solution in a is then brought exactly to the mark on the capillary stem, and after waiting the required time for drainage in the burette the sample is measured. The loss in volume shows the amount of carbon dioxide absorbed by the potassium hydroxide solution. The sample is then passed into the pipette b for the removal of oxygen. The sample is passed back and forth several times between burette and pipette in the same manner as when determining carbon dioxide. The alkaline pyrogallate solution does not, however, remove the oxygen from a gas mixture as rapidly as the potassium hydroxide solution removes carbon dioxide, therefore the sample must be kept in contact with the solution for a longer time. After the contraction in volume due to the absorption of oxygen has been noted the sample is then passed into pipette c for the removal of carbon monoxide. If after several passages of the sample in any pipette no difference in volume is observed the absorption of the gas may be considered complete. Each gas should be completely re...

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