What is the Law of definite proportions?

Law of definite proportions, statement that every chemical compound contains fixed and constant proportions (by mass) of its constituent elements. read more

The law of definite proportions might seem obvious to the modern chemist, inherent in the very definition of a chemical compound. At the end of the 18th century, however, when the concept of a chemical compound had not yet been fully developed, the law was novel. read more

The law of definite proportions is also known as Proust's law or the law of constant composition. Law of Definite Proportions Definition. The law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. read more