42 



LABOKATOKY MANUAL 



6. Number of calories used in boiling away water 

 (calculated). 



7. Number of calories required to boil away 1 c.c. 

 of water (calculated). 



8. Did the temperature rise during boiling? 



9. What became of the heat? 



Exercise 19. Effect of Pressure on Boiling- Point. 

 Object: To show the effect of lowering the pressure 

 on the boiling point of water. 



Apparatus 



Air pump 

 Flask 



Thermometer 

 Bun sen burner 

 Ring stand 



Wire gauze 

 Belljar 

 Vaseline 

 Rubber stopper 

 Beaker 



Fig. 15. 



Directions : A. Half fill a flask with Avater and place 

 it on a ring stand over the flame of a Bunsen burner. 



