Laboratory exercises in physical chemistry - Frederick Hutton Getman, Paperback

• Release Date   5/21/2012
• ISBN-13   9781236422552 | 978-1-236-42255-2
• ISBN   1236422554 | 1-236-42255-4
• Format   Paperback
• Author(s)   Frederick Hutton Getman
• 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. 1908 Excerpt: ... run smoothly, the thermometer is inserted and the stirrer set in motion. As soon as the different parts of the calorimeter system have assumed a common temperature, which usually requires two or three minutes, the mercury will begin to rise at a uniform rate, and the readings of the 'initial' or precombustion period may begin." "The room temperature may have changed so much since the apparatus was last used that the thermometer must be reset. In that event the water should be stirred a little after the insertion of the bomb and its temperature determined with an ordinary thermometer, so that the actual temperature to which the zero of the reset thermometer corresponds may be known within half a degree." Temperature Changes in the System.--" If the calorimeter system were absolutely insulated thermally, only two temperature observations would be necessary for the determination of the heat of combustion of the substance. One of these could be made at any time after the system had come to internal temperature equilibrium after the insertion of the bomb, and before the ignition of the substance, for the temperature would remain absolutely constant during this interval of time whatever might be its length. This observation would give the initial temperature of the system. The second observation, that of the final temperature, could be made at any time after the heat from the combustion had distributed itself uniformly throughout the system, for then the temperature would again remain constant." "But it is of course impossible to insulate the system completely and, consequently, external influences are continually affecting its temperature. The most obvious and doubtless the most important of these external influences is the tempera...