化工, or chemical engineering, is a branch of engineering that focuses on the design, optimization, and operation of processes that convert raw materials into valuable products. This field combines principles from chemistry, physics, mathematics, and biology to develop processes for producing chemicals, fuels, pharmaceuticals, and other materials. Chemical engineers work in various industries, including petrochemicals, food processing, and pharmaceuticals. They are involved in tasks such as process design, equipment selection, and safety management, ensuring that production is efficient, cost-effective, and environmentally friendly.