Question

How does aluminum react with ferric oxide?

Answer 1

`Fe_2O_3 + 2Al rarr 2Fe + Al_2O_3 + Delta`

Explanation:

The stoichiometric equation is balanced as it must be, and it dictates 2:1 molar equivalence between aluminum and iron oxide.

`"Moles of aluminum"` `=` `(40.5*g)/(27.0*g*mol^-1)` `=` `1.5*mol`

And, clearly, given the stoichiometry, `0.75*mol` of ferric oxide are required for equivalence, i.e. `0.75*molxx159.69*g*mol^-1` `~=120*g`.