The thermit rection used to weld iron rails in building a rail track, involves the following reaction
`Fe_(2)O_(3)+2AlrarrAl_(2)O_(3)+2Fe`
Calculate the mass of iron metal that can be prepared from 150 g of aluminium and 250 g of iron (iii) oxide.

Answer

175 g of Fe

Explanation

The thremit reaction is :
`underset(underset(=160g)(2xx56+3xx16))(Fe_(2)O_(3))+underset(underset(=54g)(2xx27))(2Al)rarr2Al_(2)O_(3)+underset(underset(=112g)(2xx56))(2Fe)`
From the available data, it is evident that 150 g of Al metal need `Fe_(2)O_(3)=((160g))/((54g))xx(150g)=444.4g`
But `Fe_(2)O_(3)` actually available = 250 g
This means `Fe_(2)O_(3)` is the limiting reactant.
The mass of Fe metal which can be prepared from 250 g of `Fe_(2)O_(3)=((112g))/((160g))xx(250g)=175g`.