Al₂O  has a higher percentage of aluminium. 
Explanation:
To solve this problem, we have to compare the molar mass of the aluminium in each compound to one another as percentage of the whole compound: 
Molar mass of Al₂O = 2(27) + 16 = 70g/mol
Molar mass of Al(NO₃)₃ = 27 + 3[14 + 3(16)] = 213g/mol
Percentage by mass of Al in Al₂O =  x 100 = 77%
 x 100 = 77%
Percentage by mass of Al in  Al(NO₃)₃ =  x 100 = 12.7%
 x 100 = 12.7%
Al₂O  has a higher percentage of aluminium. 
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I believe that #1 is the lie, but I'm not great at this subject. 
 
        
             
        
        
        
The substance would be referred to as a compound substance.
        
             
        
        
        
The five main branches of chemistry are organic chemistry, inorganic chemistry, analytical chemistry, physical chemistry and biochemistry. Chemistry can be further divided into many sub-branches that may fall under more than one of the main branches.