Question: what happens when iron reacts with oxygen and water?
Answer: Rust

Rust is another name for iron oxide , which occurs when iron or an alloy that contains iron , like steel , is exposed to oxygen and moisture for a long period of time . Over time , the oxygen combines with the metal at an atomic level , forming a new compound called an oxide and weakening the bonds of the metal itself . Although some people refer to rust generally as '' oxidation '' , that term is much more general ; although rust forms when iron undergoes oxidation , not all oxidation forms rust . Only iron or alloys that contain iron can rust , but other metals can corrode in similar ways .