<span>remember that all elements want to have no valence electrons, they want to be like the noble gases. Oxygen has six valence electrons, which means that it needs to gain two to become stable. it takes much more energy for oxygen to lose its 6 valence electrons than it would be to gain 2. >>When atoms form compounds, they become stable
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2.5 mole O2 should react (2 * 2.5) = 5.0 mole H2 but there is 6.0 mole H2. H2 remain in excess. O2 is the limiting reactant. mole of H2O formed = 2 * 2.5 = 5.0 mole.
