COMPOSITION OF LIFELESS AND LIVING THINGS 7 



the oxygen begins to be given off. Fill three or four bottles with 

 water, cover each with a piece of glass or cardboard, and invert the 

 first one over the mouth of the delivery tube, removing the cover 

 when the mouth is under water. Continue to heat the mixture 

 until the bottle is full of oxygen, then cover it under water with the 

 glass plate or cardboard, and stand it right side up on the table. 

 In the same way fill as many jars as are needed for the experiments 

 with oxygen. (Fig. 1.) 



FIG. 1. Preparation of oxygen. 



Prepare several bottles of oxygen as directed and allow them to 

 stand until all fumes have settled, before answering the following 

 questions. 



1. Examine a bottle of oxygen. 



a. State what you have done. 



b. Do you find oxygen to be a solid, a liquid, or a gas ? 



c. State whether or not oxygen has color. 



2. Heat some charcoal (carbon) till it glows and thrust it 



into a bottle of oxygen. 



a. Tell what was done and describe what happens. 

 6. Does carbon burn better in air (which is a mixture of 



oxygen and other gases) or in pure oxygen ? 



3. State the three characteristics of oxygen which you have 



learned. 



11. Carbon dioxid (formula, CO 2 ). Laboratory Study 

 No. 3. Demonstration. 



