The chemistry of plant and animal life . utiously to the flame should be moved from time to time, and not allowed tostrike just one part of the test-tube, otherwise the glass will melt,and the test-tube collapse. As soon as bubbles of gas are given oflEfreely from the water, place the end of the delivery tube so thatthe gas is collected in one of the cylinders. When a cylinderis filled, cover it with one of the glass plates, while the mouth ofthe cylinder is still under water. It can then be placed uprightupon the desk, and another cylinder filled with O. After collect-ing three
The chemistry of plant and animal life . utiously to the flame should be moved from time to time, and not allowed tostrike just one part of the test-tube, otherwise the glass will melt,and the test-tube collapse. As soon as bubbles of gas are given oflEfreely from the water, place the end of the delivery tube so thatthe gas is collected in one of the cylinders. When a cylinderis filled, cover it with one of the glass plates, while the mouth ofthe cylinder is still under water. It can then be placed uprightupon the desk, and another cylinder filled with O. After collect-ing three or four cylinders of gas, remove the end of the deliverytube from the water, and then remove the flame. Do not removethe flame while the end of the delivery tube is under water, or avacuum will be formed, and the water will rush back into the test-tube. Tests should be made with the O as follows : (i) Light a splinter and place it for a moment in one of the cyl-inders of oxygen (see Fig. 15) ; remove it ; extinguish the flame, OXYGEN 33. and while the splinter is still glowing, thrust it into the cylinderagain. Observe the result in each case. (2) Put a small piece ofsulfur, a little larger than a grain of wheat, into the iron or defla-gration spoon ; ignite in the flame, andthen thrust into another cylinder of the result. (3) Take a piece ofbright fine iron wire or watch-spring, andmake it into a spiral with a loop at oneend. Warm the wire by holding it nearthe flame, then hold the loop for an in-stant in the flame and dip it into somesulfur which has been placed on a pieceof paper. Hold again in the flame for amoment and then place at once in thethird cylinder of O. In order to insurethe success of this experiment, the wireshould be very fine, free from rust, andheld in the flame only long enough tostart ignition, and then placed in thecylinder. Questions, (i) Where does the O in the cylinder come from ?(2) What caused it to separate from the compound ? (3) What ist
Size: 1196px × 2088px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublishernewyorklondonthema
