9 2 ANSWERS TO PRACTICAL QUESTIONS 



Our muscles, as well as the food from which they are 

 formed, consist of complex molecules, and the tension of 

 the forces is very great. When they oxidize, the potential 

 force becomes a dynamic one. 



26. Does the plant PRODUCE force'! 



(See Chemistry, page 100.) 



It only gathers up the solar force. 



27. If 'we burn an organic body in a stove,, it gives off 

 heat ; in the body it produces also motion. Explain. 



The force set free by the oxidation of the muscles, and 

 food within the body is, by the principle of the correla- 

 tion of forces, converted into muscular energy. 



28. In preparing N a thin, white cloud remains in the 

 Jar for a long time. What is it ? 



Probably an antozone cloud. 



49. i. How could you detect any free O in ajar 0fN ? 



By passing into the jar a bubble of NO, and watching 

 for the production of the red fumes of NO 2 . 



2. How would you remove the product of the test? 

 By letting the jar stand over water. 



3. In the experiment shown in Fig. 1 1, why is the gas red 

 in the flask, but colorless when it bubbles up into the jar ? 



Because the NO 2 formed by the air present in the flask 

 is absorbed by the H 2 O in the pneumatic tub. 



4. How much H 3 N can be obtained from 3 Ibs. of sal- 

 ammoniac ? 



