EXERCISE 46 



HOW IS WATER DISTILLED, AND HOW MAY DISSOLVED SOLIDS BE SEPARATED 



FROM WATER? 



Materials. Apparatus of the preceding exercise ; a bent glass 

 tube ; test tube ; beaker or cup ; salt. 



Directions. Place about 100 cubic centimeters of water in a flask 

 and add 3 or 4 teaspoonfuls of salt. Shake it to hasten solution. Taste 

 the solution. Now connect a delivery tube as shown in the diagram, 

 and heat the solution to boiling. Keep the water in the beaker cold 

 by adding ice or snow. Observe what happens. After five minutes of 

 boiling remove the beaker and test tube, also the burner. Taste the 

 liquid that has distilled over into the receiver. This is called the 

 distillate. Is any salt present? 



Additional problems. Put ink or other colored liquid in a flask of water. 

 Determine whether the coloring material is present in the distillate. 

 How could you obtain fresh water from salt water or sea water ? 

 Of what commercial use is the process of distillation ? 



[62] 



