Hello, I'm making a question on the explosion of hydrogen/oxygen. All the things you need to know are the following. The formation of H-radicals in the H2-O2 mixture are responsible for ignition of the explosion. This means the H-radicals need to be formed faster than they are destructed to let the mixture explode. One of the 'termination' reaction in which H-radicals are removed is through collisions with the vessel wall. H + wall --> removal with rate constant k_1 The question now is: "Textbooks state that the rate constant k1 can be written as: k_1 = k_d / P with P the total pressure and k_d another rate constant. Assuming that the vessel is spherical with radius R, and d is the diameter of a hydrogen atom, and m its mass. Derive now the following equation: k1 = (12/ R^2) * ((kb*T ) / (Pi*d^2 * P * Srqt(2) ))* Sqrt( 8*kb*T / Pi*m) How do I do this? It has something to do with determining the collion rate to the wall and the last Sqrt-term will be from the boltzmann velocity, but I just can't see where all the terms come from.