Petroleum Refining Cracking -converts high molecular weight hydrocarbons to more useful,low molecular weight ones Reforming -increases branching of hydrocarbon chains branched hydrocarbons have better burning characteristics for automobile enginesCollege Petroleum Refining of Science ❖Cracking ◼converts high molecular weight hydrocarbons to more useful, low molecular weight ones ❖Reforming ◼increases branching of hydrocarbon chains branched hydrocarbons have better burning characteristics for automobile engines