Magnesium oxide does not readily decompose into magnesium and oxygen. The reaction is shown. MgO times s plus 601 point 7 kJ rightarrow Mg times s plus 1 half cap o sub 2 g Which factor plays the most important role in allowing this reaction to occur?

The reaction has 601.7 kJ on the reactant side, so it must absorb energy to decompose magnesium oxide. Raising the temperature supplies thermal energy and helps the reaction occur. Therefore, temperature is the most important factor; surface area, concentration, and pressure do not provide the required energy.

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