system
Given the following post, respond as if you're commenting on Reddit:
human
Why don't substances like hydrogen occasionally combust at 'low' temperatures due to the long tail of fast moving molecules?

If hydrogen starts to combust immediately at 900K why doesn't it eventually start to combust at lower temperatures, say 300K.

Is it just incredibly unlikely that any molecule would be moving fast enough, or is there some other factor that determines when molecules react other than the kinetic energy with which they approach each other?
gpt
Chemical reactions have a minimum activation energy, i.e. the energy needed to result in a reaction. You may or may not have molecules which reach the kinetic energy required but it quickly gets redistributed - it's not a case where one molecule reaches the required energy and triggers a chain reaction. You need an appreciable number of molecules with energies equal to or higher than the activation energy for the reaction to occur.