14.292 grams of Fe2O3 is formed when 10 gram of iron metal is burned.
Explanation:
The balanced equation for the reaction is to be known so that number of moles taking part can be known.
The balanced chemical equation is
4Fe + 3 ⇒ 2
⇒ 2 

From the given weight of iron to be used for the production of 
 , number of moles of Fe taking part in the reaction can be known by the formula:
, number of moles of Fe taking part in the reaction can be known by the formula:
Number of moles= mass ÷ Atomic mass of one mole of the element.
 (Atomic weight of Fe is 55.845 gm/mole)
   Putting the values in equation   
Number of moles =  10 gm  ÷ 55.845 gm/mole 
                                =  0.179 moles 
Applying the stoichiometry concept
4 moles of Fe gives 2 Moles of Fe2O3
0.179 moles will produce x moles of Fe2O3
  So,  2÷ 4 = x ÷ 0.179
      2/4 = x/ 0.179
     2 × 0.179 = 4x
      2 × 0.179 / 4 = x
   x = 0.0895 moles
So from 10 grams of iron metal 0.0895 moles of Fe2O3 is formed.
Now the formula used above will give the weight of Fe2O3 
weight = atomic weight × number of moles
             =  159.69 grams ×  0.0895
              =  14.292 grams of Fe2O3 formed.
 
        
             
        
        
        
1:1 They would have one of each per molecule