Question

The rusting of iron is represented by the equation 4Fe+3O2=2Fe2O. A 1.45-mol sample of iron, how many moles of Fe2O3 will there be after rusting has completed.

Answer 1

I think you meant to state the chemical reaction is actually:
4Fe + 3O2=2Fe2O3

That being the case, 4 moles of iron provides 2 moles of Fe2O3. Using this ratio, the amount of Fe2O3 after rusting has completed can be calculated as:
1.45*2/4=0.725 moles Fe2O3.