Answer to Question #267076 in General Chemistry for jho

Question

1. Thermite reaction is necessary to produce molten iron. This reaction involves Fe3O4 and Al and is

described by:

8 Al + 3 Fe3O4 9 Fe + 4 Al2O3

If 198.5 g Al and 365.5 g Fe3O4 are used, what mass of the excess reagent remains unused at the

end of the reaction?

Answer 1

To calculate either the excess or limiting reagent.

We use stoichiometry

If 216g of Al reacts with 232g of Fe3O4

198g of Al ...................Xg of Fe3O4

X=212.67g

Therefore Fe3O4 is the excess

To get the excess well subtract 212.67 from 365.5

Therefore the mass of the excess reagent that remains is 153g