KEROSENE OR COAL OILS 



I2S 



tilled, and the two main products of the distillation are kerosene 

 and gasoline. 



We can easily separate petroleum into some of its constitu- 

 ents in a simple manner in the laboratory. Partly fill a hard 

 glass tube with petroleum and attach it to two U-tubes as in 

 Figure 51. Let the first U-tube A rest in a beaker of boiling 

 water, and the second U-tube B rest in a beaker of cold water. 

 Heat the petroleum gently and notice the vapors or fumes 

 which rise from it and pass into the U-shaped tubes A and E. 

 The components of pe- 

 troleum which have a 

 low boiling point are 

 driven through A into B, 

 where they are chilled 

 and condensed. When 

 the petroleum is heated 

 more strongly, compo- 

 nents which have a higher 

 boiling point are driven 

 off as vapors into A. 



FIG. 51. Distillation of petroleum. 



Although the temperature of A is high, it is still low enough 

 to condense these very hot vapors. Various vapors then 

 condense and collect in A. When we pour the contents 

 of A and B into evaporating dishes and examine them, we 

 are reminded of kerosene, benzine, and gasoline. Since differ- 

 ent vapors (that is, all vapors condensing at about the same 

 temperature) condensed in A, the distillates which collect 

 there are really a mixture of several substances. The same 

 is true of the distillates in B. Benzine vapor, for example, 

 condenses if the temperature is less than 120 C., kerosene 

 condenses if the temperature is less than 150 C., and hence 

 in B we may find both kerosene and benzine. If we wish to 

 separate the distillates, we can do it by adding more U-tubes 



