posted by Danny .
Magnesium reacts with oxygen to form magnesium oxide according to the following equation:
2Mg(s) + O2(g) ==> 2MGO(s)
If 0.81 grams of magnesium oxide are formed, how many grams of oxygen reacted?
MGO and MgO are not the same.
1. You have the balanced equation.
2. Convert 0.81 grams MgO to moles. moles = grams/molar mass.
3. Using the coefficients in the balanced equation, convert moles MgO to moles O2.
4. Convert moles O2 to grams. g = mols x molar mass.