Alex saw a rusty old car in an abandoned lot. because he had recently read about chemical reactions, he began to wonder how the rust formed. what happened to cause the rust on the steel car? a. a decomposition chemical reaction took place when the iron in the steel mixed with oxygen to form rust. b. oxygen in the air reacted with the paint on the car and formed rust c. a physical change took place in the steel of the car to form rust d. oxygen in the air chemically combined with iron in the steel to form rust.

The answere is A

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.