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РЕГИСТРАЦИЯ ЭКСКУРСИЯ

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Прочтите текст про себя (контрольное время чтения — 2 минуты). Fundamentals of the Analytical Balance

Of great importance in the laboratory is the analytical balancc, one of the most common laboratory tools. Its usefulness increases when the chcmist understands its operation well enough to utilize the full capabilities and to realize the limitations of the balancc.

Some chcmistry students do not become proficient in the use of the balancc, understandably, they arc concerned with so many other and complex instruments and problems. The balancc is taken for granted. It may be that, because balances have been used for so many centuries, intuitive knowledge about them is assumed. At the other extreme are those who know there is something precise and presumably delicate about a balancc, and so they avoid using one if possible. This is unfortunate bccausc mass, along with length and time, is a fundamental measurement. An example is the use of the balancc to prepare standards for the calibration of more specialized instruments. Another important thing about a balancc is its high ratio of capacity to sensitivity. Few measurements will yield as many significant figures as weighing on an


analytical balancc. Results to six significant and cxact figures arc ordinary.

Those who have learned about balances by an intuitive process tend to think of them as tectcr-tottcrs. Actually a balancc is a compound pendulum with complications. The essentials of the operation can be understood easily, however, by visualizing an upright wheel free to turn on a fixed axle...


19.01.2015; 02:01
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Гуманитарные науки
лингвистика и языки
литературный английский
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