EXERCISE 8 (Continued) 



4. What are some of the compounds you have studied so far ? 



NOTE 3. By burning some hydrogen in air we can easily show that hydrogen com- 

 bines with oxygen to form water. Pour dilute hydrochloric acid into a flask containing 

 some small pieces of zinc covered with water. After all the air is out of the flask bring 

 a lighted match to the nozzle, and then hold a clean, dry bottle or test tube over the flame. 



CAUTION. If a flame is brought near the gas outlet while there is still 

 air in the apparatus, there is danger of a serious explosion. 



5. What proportions do you suppose you would have to use if you were to combine volumes of 

 hydrogen and oxygen for producing water ? 



TJ 



6. The chemist uses a shorthand way of writing water : TT ^> O, or H 2 O. Give whatever reasons 

 you can think of for the use of either or both of these methods of representing water. 



