INTRODUCTORY EXERCISES 



23 



into its two parts, hydrogen and oxygen.) Is this exercise 

 synthesis or analysis? 



XI. — Properties of Hydrogen (Optional). 



Apparatus. — Granulated zinc or pieces of sheet zinc, dilute sul- 

 phuric acid,^ bottle with two-holed stopper, thistle tube, glass and 

 rubber connecting tubing, pneumatic trough, large-mouthed bottle, 

 test tubes. 



Directions. — Set up the apparatus as in the diagram. 

 Place a handful of zinc in the bottle and pour on enough 

 dilute sulphuric acid through the thistle tube to cover the 

 zinc. (Caution! Keep all _ 

 flames away from the ap- 

 paratus until the gas is col- 

 lected.) Let this gas escape 

 until it is bubbling freely 

 from the delivery tube ; then 

 collect the large bottle full 

 through water as in Ex. 

 VIII.2 



A. By the method of Ex. 

 II, B, take some of the gas 

 in a test tube and examine it, holding the test tube mouth 

 downward. Has it any color? odor? taste? 



B. Collect a second test tube full and hold mouth down- 

 ward as before. Tie a match to a wire, Hght the match, and 

 thrust it up into the tube. Does the match continue to 



Fig. 10. 



^ To dilute sulphuric acid, pour slowly one part of acid into five or six parts 

 of water. Stir while pouring. 



2 The gas will be freer of impurities if passed through a wash bottle con- 

 taining permanganate solution. 



