Which arrow represents the change of state described above?
The diagram shows changes of state between solid,
liquid, and gas. The atoms of a substance lose energy
during a change of state. Before the change, the atoms
are close together but are able to slide past one
another
M
N
gas
M
zo
Р
molid
liquid

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.