Perhaps you have noticed the dull, white substance that appears on an aluminum screen door. This substance is aluminum oxide, Al2O3, and it forms from the reaction of aluminum metal, Al, and oxygen, O2. Which of these chemical equations is correct for this reaction? A. Al + O2 → Al2O3
B. 2 Al + O2 → Al2O3
C. 2 Al + 3 O → Al2O3
D. 4 Al + 3 O2 → 2 Al2O3

Which of the following warnings would an agricultural chemist tell a farmer who wants to recycle his or her own ammonia? recycling ammonia is a difficult process that sometimes takes weeks. recycling ammonia requires a degree in biochemistry or a related field. recycling ammonia can be harmful because it is highly flammable and toxic. recycling ammonia costs too much money considering the price of the necessary chemicals.