Which statement best describes combustion?

• A. A chemical process of oxidation that occurs at a rate fast enough to produce heat and usually light in the form of a glow or a flame
• B. A physical process of dissolution
• C. A biological process of growth
• D. A chemical process of hydration

Answer: (A)

Combustion is a rapid exothermic oxidation that releases heat and usually light in the form of a glow or a flame. It’s a chemical change where a fuel reacts with an oxidizer (commonly oxygen) to produce heat and often light, with new products like carbon dioxide and water. The emphasis on "rapid enough" is important because oxidation can occur slowly (like rust) without noticeable heat or light, which is not considered combustion. The other options describe different processes: dissolution is a physical change, growth is a biological process, and hydration is a chemical change involving water but not the rapid, heat-and-light oxidation characteristic of combustion.