Answer:
12 moles of MgO
1.8 moles of Oâ‚‚
5.5 moles of Mg
Explanation:
These questions are all related and they involve comparing the number of moles of reactant to products.
Here we use molar relationship because they express what happens in a reaction much more better.
Problem 1:
           2Mg   +   O₂   →   2MgO
We work from the known to the unknown;
       The known is oxygen gas;  which is 6moles
            Unknown is MgO;
          1 mole of O₂ produced 2 mole of MgO
          6 moles of O₂ will produce  (6 x 2) moles of MgO
                                  = 12 moles of MgO
Problem 2:
        2Mg   +   O₂   →   2MgO
      Known;  3.6 moles of Magnesium
      Unknown;  number of moles of oxygen;
      2 moles of Mg reacted with 1 mole of O₂
     3.6 moles of Mg will react with  [tex]\frac{3.6}{2}[/tex]  = 1.8 moles of O₂
Problem 3:
       2Mg   +   O₂   →   2MgO
      Known: number of of moles of MgO  = 5.5moles
      Unknown: number of moles of Mg = ?
     2 moles of MgO will be produced from 2 moles of Mg
     5.5 moles of MgO will be produced from [tex]\frac{5.5 x 2}{2}[/tex]  = 5.5 moles of Mg
