If 56.98 g of iron filings ..

the balanced chemical equation is 2Fe + 3Cu2SO4= 2FeCu3 + 3SO4

This is a joke, right!

Firstly, there is no such thing as copper(I) sulphate. Copper(I) is only stable in certain circumstances such as in the solid state (e.g. copper(I) oxide) and in solution in the presence of certain ligands such as NH3.

Secondly, there is no such thing as SO4. This implies sulphur in oxidation state +8 but the maximum for sulphur is +6. If you meant SO4虏藟 (i.e. sulphate ion) then the equation is not balanced as you have excess charge on the right hand side.

There is an alloy which crystallises with the formula FeCu3 but it is not formed in this way.