Why does oil have to be processed or change before it can be used?

Oil must be processed or refined to remove impurities, separate different hydrocarbon components, and convert them into usable products like gasoline, diesel, and jet fuel. Raw crude oil contains various substances, including sulfur, heavy metals, and other contaminants that can be harmful or inefficient in engines. Refining transforms crude oil into a range of valuable products through processes such as distillation, cracking, and reforming, ensuring that the final fuels meet regulatory standards and performance requirements.