When a reaction occurs where does the energy to cross the activation energy comes from?My book states that it might look like there is violation of conservation of energy but the physics of small particles is different.
The energy to cross the activation energy doesn’t come out of nowhere. Many times it’s something like heat (which is basically how fast the particles are moving). For example, paper doesn’t combust to ash automatically. But heat it to 218 or so degrees centigrade, (including Fahrenheit 451) and it will auto ignite. This is due to the energy the heat provides.