Which of the following best describes the process of cracking?

The process of cracking is best described as breaking larger molecules into smaller ones. This process is integral to refining crude oil as it transforms heavy hydrocarbon fractions, which are less desirable, into lighter, more valuable products like gasoline, diesel fuel, and other chemicals.

Cracking occurs through various methods, including thermal cracking, where high temperatures are used to cause the breakdown of large molecules, and catalytic cracking, which uses a catalyst to facilitate the process at lower temperatures and pressures. The ability to break down heavy oils and feedstocks into lighter hydrocarbons allows refineries to maximize their yield of more valuable products from the raw materials they process.

While restructuring of molecules can occur during processes like isomerization, the primary focus of cracking is on the physical breaking down of molecular chains rather than just altering their structure or configuration. Removing contaminants and separating fractions are essential steps in the refining process, but they relate more to treating and purifying crude oil rather than the specific action described by cracking.