whta important contribution did lavoisier make to dalton's atomic theory of matter?

Answer 1

In 1802, John Dalton proposed the "modern form" of the atomic hypothesis. However, 58 years later the best chemists in the world still thought that the correct molecular formula for water was "HO". Some questions should be stated:

How do we know the molecular formula of any compound - such as H2O?
What gives us the right to say that one atom of carbon (C) is approximately 12 times as heavy as one atom of hydrogen (H)?
How are atomic numbers for the elements obtained?
Why do the atoms with the same atomic number but different atomic weights (isotopes) have (nearly) the same chemical properties?
How do we know that the negative charges in an tom are on the "outside" and that most of the mass of the atom is compressed into a tiny dense nucleus of positive charge?
What do we mean by the "radius" of an atom? Should not the size of the atom be as difficult to measure as its mass (weight)?
What laboratory measurements can be related to such "microscopic" parameters?
As Alexander Smith alluded to above, how do we know that atoms exist at all? As mentioned previously, even the alchemists had a "reductionist" view of matter as being ultimately composed of Air, Earth, Fire, and Water. It turns out that Antoine Lavosier and John Dalton (among others) demonstrated that the fundamental units in chemical reactions are atoms.