#cracking  the process whereby heavy molecules of naphtha or petroleum are broken down into hydrocarbons of lower molecular weight (especially in the oil-refining process)
  supertype:  chemical_process__chemical_change__chemical_action  any process determined by the atomic and molecular composition and structure of the substances involved
  subtype:  hydrocracking  the process whereby hydrocarbon molecules of petroleum are broken down into kerosene and gasolene by the addition of hydrogen under high pressure in the presence of a catalyst

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