17. According to the inorganic theery in which form does the petrolcum is found under the earth's crust 18- A comples misture of aromatic and heterocyclic compounds is 19. is the unit used to measure the dynamic viscosity 21= is used aviation fucl cold-weather performance 22 contains small amounts of hydrogen sulfide and carbon dioxide 23. the lowest temperature at which it can vaporize to form an ignitable mixture in air