|Sodium peroxide (yellow powder) and zinc powder
(gray powder in the bowl) are combined
|Water is squirted in; the mixture ignites|
|Violent, strong exothermic reaction||Burning zinc powder|
|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 + ZnOBoth 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 + H2O2The 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).