This is one of the most fundamental laws of
chemistry and is credited to Antoine Lavoisier who is often
called the father of modern chemistry. His experiments in the
late 1700's led him to this conclusion without any understanding
of atoms or other particles we now take for granted.
Lavoisier's concept is important because it
suggested to later scientists that the particles one starts with
in a reaction are the same as the those one ends up with.
To us that means that only the arrangement of particles changes
during a chemical reaction.
