How many moles of vanadium atoms, V, are needed to combine with 0.725 mol of O atoms to make vanadium pentoxide,V2O5?

Answer 1

4V + 5O2 ==> 2V2O5
0.725 mol O x (4 mols V/10 mols O) = ?

Answer 2

4.34 How many moles of vanadium atoms, V, are needed to combine with 0.565 mol of O atoms to make vanadium pentoxide, V,0,?