166 APPLIED SCIENCE 



chemical solution, instantly available, makes a large supply 

 of water unnecessary. 



Questions 



1. Why is a knowledge of the chemistry of common industrial 

 substances desirable? 



2. What is the meaning of the expression "carbon has four 

 allotropic forms"? 



3. Why do people prefer crystalline to powdered forms of 

 substances? 



4. Describe the importance of the different forms of carbon. 



5. Explain the formation of the oxides of carbon. 



6. Draw a sketch of an ordinary yellow gas flame and explain 

 why it is luminous (bright) compared to the blue flame of the gas 

 stove. Which is hotter? 



7. What is an alcohol? Carbohydrate? Fat? Soap? Oil? 

 Give an example of each kind. 



8. What is sand? 



9. Describe briefly the following: a dye; clay; gunpowder; 

 bleaching; bick; mortar; cement; porcelain. 



10. What is spontaneous combustion? 



11. Explain the action of the chemical solutions used in fire 

 extinguishers. 



