Combustion of Magnesium

Hazards

Magnesium burns extremely bright. Do not look directly at the flame.

Chemicals and Solutions

Magnesium

Materials

• Bunsen burner
• Matches
• Crystallization dish for magnesium
• Tweezers

Procedure

1. Hold the magnesium using tweezers, and light it in a bunsen burner.
2. Add burnt Mg ribbon to crystallizing dish containing water and phenolphthalein. Indicator turns pink.

Discussion

$2\mathrm{Mg}{\phantom{A}}_{(\mathrm{s})}+\mathrm{O}{\phantom{A}}_2{\phantom{A}}_{(\mathrm{g})}⟶2\mathrm{MgO}{\phantom{A}}_{(\mathrm{s})}\mathrm{\Delta }\mathrm{G}{\phantom{A}}_{\mathrm{Rxn}}^{\text{o}}=-1139\mathrm{KJ}/\mathrm{Mol}$

$\mathrm{MgO}+\mathrm{H}{\phantom{A}}_2\mathrm{O}⟶\mathrm{Mg}(\mathrm{OH}){\phantom{A}}_2\mathrm{\Delta }\mathrm{G}{\phantom{A}}_{\mathrm{Rxn}}^{\text{o}}=-27\mathrm{KJ}/\mathrm{Mol}$