In a compound the elements are always presents in definite proportions by___

The correct answer is Mass.

Key Points

• In a compound, the elements are chemically combined in a fixed proportion by mass.
• The Law of definite proportions states that a compound will always contain the same proportion of elements by mass.
• It was given by Proust.
• Lavoisier discovered the role of oxygen in combustion.
• Democritus was a Greek Mathematician.
• Dalton gave the atomic theory which states that the atom of different size varies in size and mass.