Describe the experiment conducted by Joseph L., Proust, which lead him to purpose law of constant proportions.

Explanation

1) Proust look two samples of copper carbonate, one from nature and another prepared in the lab.
2) These two samples are chemically decomposed to find percentage of copper ,carbon and oxygen.
3) The results obtained are given in the table.

4) From the above table we observe that the percentage of copper, carbon and oxygen atoms in two samples are same.
5) Bases on this observation Proust proposed the law of constant proportions as "A given chemical substances always contains the same elements combined in a fixed proportions by weight".