CARBOX 67 



Preparation and test for carbon dioxide. Carbon 

 dioxide may be supplied in many ways, but the sim- 

 plest method for class use is to place a few pieces of 



Fig-. 29. The action of the hydrochloric acid on the pieces of 

 marble in the test tube decomposes them, releasing carbon dioxide. 

 The gas escapes through the bent tube into the bottle. 



marble in a test tube, and pour hydrochloric acid on it. 

 In the chemical action which takes place between the 

 marble and the hydrochloric acid, carbon dioxide is 

 given off and a salt (calcium chloride) and water are 

 left in the tube. 



If a bottle of this gas is collected it will be found 

 to be colorless, with little taste or odor. It is about 

 I l /2 times as heavy as air and thus can be collected 



