QUESTIONS. 97 



plants? Name the non-metallic elements. The metals. What 

 other elements are sometimes present? 



19. What is said of oxygen ? How prepared ? What should 

 be mixed with the potassium chlorate ? 



20. Properties of oxygen ? What is combustion ? Give ex- 

 amples. 



21. With what elements does oxygen unite? What are 

 these compounds called? How named? What is potash? 

 What is lime? 



22. Give cases of oxidation without light and intense heat? 

 What happens in breathing? Can animals live without oxy- 

 gen ? Can plants ? 



23. What is said of hydrogen? How is it prepared ? 



24. Properties of hydrogen ? Result of its combustion ? 



25. How is water formed? What does it form when con- 

 densed in the air? Where do natural waters get the mineral mat- 

 ter contained in them ? What kind of water is the purest? Why? 



26. Where is nitrogen found ? How much is in the air ? 

 How is it prepared ? 



27. Properties of nitrogen? Is it poisonous? How can 

 oxygen, hydrogen, and nitrogen, be distinguished ? 



28. What is ammonia? How made? How much does 

 water absorb ? What is hartshorn ? Why is ammonia called 

 an alkali ? 



29. How is ammonia formed naturally? How does it get 

 into plants ? 



30. What is nitric acid ? What does it form with metals ? 

 What is nitre? Chili saltpetre? How used? 



31. In what forms does carbon exist? Is it abundant in 

 plants ? What per cent, in sugar ? In turpentine ? What 

 makes smoke black ? 



32. What is carbon dioxide ? Where found ? What are its 

 properties ? 



33. What is silicon ? Is it necessary to plants ? Where 

 is it found ? 



