Simple chemical reactions involve a single change in the identity or composition of a substance, resulting from a reaction between two or more different molecules. Full definition
All of them tend to form by simple chemical reactions between smaller components or through the activity of radicals and neutral molecules on the surface of floating dust grains. (discovermagazine.com)
One way to do this is to store the hydrogen in safe materials that release the hydrogen on demand via simple chemical reactions. (pnnl.gov)
Fuel cells rely on a relatively simple chemical reaction to generate energy. (peakoil.net)