Glow chip sample
In chemistry, the term glow chip sample denotes a qualitative detection of oxygen (O 2 ).
If you hold a piece of wood , the flame of which has been extinguished after igniting the glowing embers, in a vessel with the gas to be checked , the smoldering piece of wood flames up in the presence of higher concentrations of oxygen and burns again.
The glow chip sample is often used for demonstrations, as it is easy to demonstrate the formation of oxygen in a chemical reaction , provided that the presence of nitrous oxide can be excluded. The evidence is based on the fact that the burning of the smoldering chip is limited by the transport of oxygen. If the oxygen concentration increases, the rate of the exothermic reaction increases . The resulting heat of reaction causes the wood chips to flare up again and the transport of oxygen is supported by the rising warm gases.
Glowing wood chip (Glimmspan)
Electrolytically obtained oxygen, which escapes from the collecting vessel, ignites a flame on the glowing wood chips
Smoldering wood chips that ignite brightly in pure oxygen
Uniqueness
Also nitrous oxide (N 2 O, "laughing gas") shows a similar fire-promoting effect as O 2 , so the glowing splint is no clear detection method for oxygen.