Why cooking gas has a typical smell

In the derivation of rrkm theory, a factor of 1/2 is introduced when equalizing the rates of formation and decomposition of activated complex as keal-hr) = ko this is clearly against the assumption of transition state theory that states all the activated complex in the transition state iss going to the product. find the reason why this factor is introduced here.

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.

Explain why electric current cannot exist if a current doesn't have a voltage source.