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A School Chemistry; Intended for Use in High Schools and in Elementary Classes in Colleges
A School Chemistry Intended for Use in High Schools and in Elementary Classes in Colleges Author:John Waddell General Books publication date: 2009 Original publication date: 1900 Original Publisher: The Macmillan Company Subjects: Chemistry Science / Chemistry / General Notes: This is a black and white OCR reprint of the original. It has no illustrations and there may be typos or missing text. When you buy the General Books edition of this book ... more »you get free trial access to Million-Books.com where you can select from more than a million books for free. Excerpt: CHAPTER III OXYGEN We have seen that when water is electrolysed oxygen as well as hydrogen is produced, and a good deal of oxygen is now made in this way ; but in laboratories not supplied with electrical power other methods are used. We saw that hydrogen can be obtained from water by the action of substances which take away oxygen, and it might be possible to produce oxygen from water by the action of something which would take away the hydrogen. There is no convenient substance for doing this, however. If steam is heated to a sufficiently high temperature it is decomposed into oxygen and hydrogen, but it is not easy to separate the two gases, though it is not impossible to do so. We found that oxygen exists in the air, but in this case also it is difficult to separate the other constituents which are with it in the atmosphere. Oxygen obtained from Compounds by Heat. -- There are some substances containing oxygen which decompose on being heated, yielding oxygen gas. In 1772 the Swedish chemist Scheele obtained it by heating nitre, a substance which is often called saltpetre, and which chemists now call potassium nitrate. Scheele named the gas " fire air," because of the great readiness with which many substances burn in it. The name oxygen was not given till some time afterward. In 1774 an Englishman, Priestley, not knowing of Scheele's work, discovered the gas by heating red lead, a substance used in the manufacture of some red paints. Priestley later on used " red precipitate " or " calcined mercury...« less