Which term best describes this reaction? 2 carbons double bonded to each other, with CH 3 above the left C and H above the right C and below both. A lowercase n appears next to the left C. Right arrow. StartBracket across single bond to 2 carbons single bonded to each other, and C H 3 above the left C and H above the right C and below both; single bond from C across EndBracket; lowercase n beside the EndBracket. condensation polymerization addition polymerization hydrohalogenation hydration

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.