Liver can also be used as a catalyst for an interesting twist. When we use peroxide to sterlize a wound, the iron in our blood acts as the catalyst to cause the release of the oxygen. Iron in the liver acts the same way. Chemists almost always use Manganese, iron's nearest neighbor on the periodic table, to do this demonstration. The toothpick or splint will reignite because oxygen supports combustion.
Combustion is the chemical combination of a substance with oxygen.
An oxide is the product. Oxygen is lighter than air so it would escape if a lid or stopper were not used. If you are using glass bottles or jars, the containers should be wrapped with a cloth. Do not have open flames or sparks near gas production or storage area.