Chemical changes are also called chemical reactions; when
this occurs substances are changed into different substances and its
composition is completely different from its original state. Wood burning is a
chemical change or process. When heat is applied on wood through the form of
fire, the wood transforms into carbon dioxide, water vapor, and ash.
The other examples mentioned in the choices are called
Physical Changes. This refers to the changes in matter from one phase to
another. Examples are when solids turn into liquids, liquids turn to gas, and
gas turns to liquids.