In petroleum geology and chemistry , cracking is the process whereby complex organic molecules such as kerogens or heavy hydrocarbons are broken down into simpler molecules -LRB- e.g. light hydrocarbons -RRB- by the breaking of carbon-carbon bonds in the precursors .

In chemistry terms , cracking is a process by which complicated organic molecules -LRB- such as kerogens or heavy hydrocarbons -RRB- are broken down into simpler molecules -LRB- e.g. light hydrocarbons -RRB- by breaking their carbon-carbon bonds .
