Question

Over the years, the thermjte reaction has been used for welding railroads, in incendiary bombs, and to ignite solid fuel rocket monitors. The reaction is Fe2O3(s) + Al(s) ---> 2Fe(l) + AI2O3(s). What mass of iron (iii) oxide(rust) must be used to produce 15.0g of molten iron.

Answer 1

Fe2O3(s) + 2Al(s) = 2Fe(l) + Al2O3(s)

n(Fe) = 15.0g/55.8g/mol = 0.269 mol
n(Fe2O3) = 0.269mol/2 = 0.135 mol
m(Fe2O3) = 0.135mol*159.7g/mol = 21.6 g