10.5 Mock Sun

Chemical Concept Demonstrated: Chemistry of phosphorus

Demonstration:

A flask is filled with O2, and phosphorus is ignited and immersed in the flask (picture #2).

Observations:

    The phosphorus lights up brightly.  As the flask fills with smoke, the entire flask gives off a uniform glow.

Explanation:

    Phosphorus reacts with oxygen in an exothermic reaction:

    P₄ (s) + O₂ (g) --> P₄O₁₀ (s)

    This reaction produces so much light that it is nicknamed the "Mock Sun."