Author: Julius William Sturmer

Publisher:

Published: 2015-07-03

Total Pages: 98

ISBN-13: 9781330631874

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Excerpt from Elementary Course in Quantitative Chemical Analysis: With Special Reference 1. The balance should rest on a perfect level, and should be adjusted so that the right and left arms exactly counterpoise. 2. A small wide-mouthed bottle, half filled with concentrated sulphuric acid (or recently ignited potassium carbonate) should be placed in the balance case, for the purpose of keeping the air in the case practically free from moisture. 3. Substances or vessels should never be weighed while hot. And to prevent the deposition of moisture on them, they should be cooled in dried air, - i. e., in a desiccator over sulphuric acid or calcium chloride. 4. Volatile substances, as well as very hygroscopic substances, should be weighed in closed containers. The method of weighing by difference should be employed. This consists simply in weighing a quantity of the substance in the container, removing a convenient quantity for analysis, and again weighing the container with the remainder of the substance. The difference between the two readings is the amount of substance taken. 5. The substance to be weighed should never be placed upon the bare balance pan; weighing glasses should always be used. 6. The substance to be weighed should always be placed upon the left balance pan, and the weights upon the right. 7. In transferring the container with the substance from the desiccator to the balance, forceps should be used, and not the fingers. Neither should weights ever be handled with the fingers. 8. The swinging of the balance beam should always be arrested before placing weights, or articles to be weighed, upon the balance pans, and before removing the same from the balance pans. 9. In weighing, the weights should be tried systematically, beginning with the large ones and working downward. 10. The doors of the balance case should not be allowed to remain open longer than necessary. The case must be closed when the final adjustment is made with the rider. When the pointer swings to an equal distance on either side of the central line (or zero-point), the balance is in equilibrium. 11. In reading weights, but two units should be used, - grammes and milligrammes. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Download or read book Elementary Course in Quantitative Chemical Analysis written by Julius William Sturmer and published by . This book was released on 2015-07-03 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Elementary Course in Quantitative Chemical Analysis: With Special Reference 1. The balance should rest on a perfect level, and should be adjusted so that the right and left arms exactly counterpoise. 2. A small wide-mouthed bottle, half filled with concentrated sulphuric acid (or recently ignited potassium carbonate) should be placed in the balance case, for the purpose of keeping the air in the case practically free from moisture. 3. Substances or vessels should never be weighed while hot. And to prevent the deposition of moisture on them, they should be cooled in dried air, - i. e., in a desiccator over sulphuric acid or calcium chloride. 4. Volatile substances, as well as very hygroscopic substances, should be weighed in closed containers. The method of weighing by difference should be employed. This consists simply in weighing a quantity of the substance in the container, removing a convenient quantity for analysis, and again weighing the container with the remainder of the substance. The difference between the two readings is the amount of substance taken. 5. The substance to be weighed should never be placed upon the bare balance pan; weighing glasses should always be used. 6. The substance to be weighed should always be placed upon the left balance pan, and the weights upon the right. 7. In transferring the container with the substance from the desiccator to the balance, forceps should be used, and not the fingers. Neither should weights ever be handled with the fingers. 8. The swinging of the balance beam should always be arrested before placing weights, or articles to be weighed, upon the balance pans, and before removing the same from the balance pans. 9. In weighing, the weights should be tried systematically, beginning with the large ones and working downward. 10. The doors of the balance case should not be allowed to remain open longer than necessary. The case must be closed when the final adjustment is made with the rider. When the pointer swings to an equal distance on either side of the central line (or zero-point), the balance is in equilibrium. 11. In reading weights, but two units should be used, - grammes and milligrammes. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.