Chemical changes occur when a substance combines with another to form a new substance, called synthesis or, alternatively, decomposes into two or more different substances.
(Chemical changes; occur; T:when a substance combines with another to form a new substance,) (a substance; combines; with another; to form a new substance) (a new substance; called alternatively; synthesis)
Chemical changes a substance a new substance
occur combines called alternatively
T:when a substance combines with another to form a new substance,
with another to form a new substance
synthesis