10.5 Mock Sun

Chemical Concept Demonstrated: Chemistry of phosphorus


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


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


    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."