PREFATORY NOTE. These laboratory exercises form a part of the "Essentials of Chemistry," and contain specific directions for laboratory work. All the exercises are intended for the student, and are so arranged that they may be used in schools having either one-hour or two-hour laboratory periods. The experiments require only common materials and simple apparatus. The quantities of materials have been stated definitely and accurately. Where possible, the directions call for fractional parts of a test tube, so that unnecessary weighing may be avoided. The test tube meant is the ordinary 5X inch tube found in most laboratories. In the revised edition of the laboratory exercises the order of the experiments has been altered to bring it into harmony with the revised text. Many of the experiments have been rewritten, and several new ones have been added. The quantitative exercises are not numerous. They have been selected for their importance in showing the weight relations of chemical reactions. All have been thoroughly tested, and have succeeded in the hands of average students. For the earlier quantitative experiments the object of the experiment and the method used have been described briefly at the beginning of the exercise, so that the student may have a better appreciation of the directions he is to follow and of the result sought. |