4.1.1 Exothermic Reaction

1.Sodium peroxide (yellow powder) and zinc powder (gray powder in the bowl) are combined 2.Water is squirted in; the mixture ignites
Sodium peroxide (yellow powder) and zinc powder
(gray powder in the bowl) are combined		 Water is squirted in; the mixture ignites
3.Violent, strong exothermic reaction 4.Burning zinc powder
Violent, strong exothermic reaction Burning zinc powder
Animation of Experiment (GIF Format, 401 k)
Animation of Experiment (MPG Format, 405 k)
Photo 1:Experimental setup: 50 g zinc dust and 15 g sodium peroxide are mixed in a metal bowl.
Photo 2 - 4:Adding water ignites the mixture. Sodium peroxide is a strong oxidizing agent and reacts with the zinc powder according to:

Na2O2 + Zn        > 2 ZnO
 The surplus zinc powder reacts with atmospheric oxygen (combustion):

2 Zn + O2        > Na2O + ZnO
Both reactions are strongly exothermic, i.e. (heat) energy is set free.

The addition of water merely begins the reaction. Sodium peroxide reacts with water in an exothermic reaction according to:

Na2O2 + 2 H2O        > 2 NaOH + H2O2
The hydrogen peroxide produced decomposes into water and oxygen under the catalyzing influence of sodium hydroxide in a reaction that is likewise exothermic. The high temperatures produced then serve to ignite the reactant mixture (zinc and sodium peroxide).
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