请输入您要查询的英文单词:

 

单词 marsh test
释义

Marsh test


Marsh test,

method for the detection of arsenicarsenic
, a semimetallic chemical element; symbol As; at. no. 33; at. wt. 74.92160; m.p. 817&degC; (at 28 atmospheres pressure); sublimation point 613&degC;; sp. gr. (stable form) 5.73; valence −3, 0, +3, or +5.
..... Click the link for more information.
, so sensitive that it can be used to detect minute amounts of arsenic in foods (the residue of fruit spray) or in stomach contents. The sample is placed in a flask with arsenic-free zinc and sulfuric acid. Arsine gas (also hydrogen) forms and is led through a drying tube to a hard glass tube in which it is heated. The arsenic is deposited as a "mirror" just beyond the heated area and on any cold surface held in the burning gas emanating from the jet. Antimony gives a similar test, but the deposit is insoluble in sodium hypochlorite, whereas arsenic will dissolve. The test was named for its inventor, the English chemist James Marsh.

Marsh test

[′märsh ‚test] (analytical chemistry) A test for the presence of arsenic in a compound; the substance to be tested is mixed with granular zinc, and dilute hydrochloric acid is added to the mixture; gaseous arsine forms, which decomposes to a black deposit of arsenic, when the gas is passed through a heated glass tube. Also known as Marsh-Berzelius test.

Marsh test


Marsh test

(marsh) [James Marsh, Brit. chemist, 1789–1846] A test to detect the presence of arsenic.

Marsh,

James, English chemist, 1789-1846. Marsh test - for detection of arsenic.
随便看

 

英语词典包含2567994条英英释义在线翻译词条,基本涵盖了全部常用单词的英英翻译及用法,是英语学习的有利工具。

 

Copyright © 2004-2022 Newdu.com All Rights Reserved
更新时间:2024/12/23 21:26:10