law of conservation of mass, lavoisier

Law of conservation of mass was introduced by Antoine Lavoisier

The matter can neither be created , nor distroyed. But one form of the matter can be convert to another form


The law of conservation of mass, or principle of mass conservation, states that for any system closed to all transfers of matter andenergy(both of which have mass),themassof the system must remain constant over time, as system mass cannot change quantity if it is not added or removed. Hence, the quantity of mass is "conserved" over time. The law implies that mass can neither be created nor destroyed, although it may be rearranged in space, or the entities associated with it may be changed in form, asfor example when light orphysicalworkis transformed into particles that contribute the same mass to the system as the light or work had contributed. The law implies (requires) that during anychemical reaction,nuclear reaction, orradioactive decayin an isolated system, the total massof the reactants or starting materials must be equal to the mass of the products.

law of multiple proportion, john dalton

Law of multiple proportion introduced by,                             JOHN DALTON

   


In chemistry, thelaw of multiple proportionsis one of the basiclawsofstoichiometryused to establish theatomic theory, alongside thelaw of conservation of mass(matter) and thelaw of definite proportions. It is sometimes calledDalton's Lawafter its discoverer, theBritishchemistJohn Dalton,who published it in the first part of the first volume of his "New System ofChemical Philosophy" (1808).The statement of the law is:

If twoelementsform more than onecompoundbetween them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of smallwhole numbers.

law of definite proportion,joseph proust

        Introduced by,joseph proust

 Law of definite proportions

Inchemistry, thelaw of definite proportions, sometimes calledProust's LaworThe Law of Definite Composition, states that achemical compoundalways contains exactly the same proportion ofelementsby mass. An equivalent statement is thelawof constant composition, which states that all samples of a given chemical compound have the same elemental composition by mass. For example,oxygenmakesup about8/9of the mass of any sample of purewater, whilehydrogenmakes up the remaining1/9of the mass. Along with thelaw of multiple proportions, the law of definite proportions forms the basis ofstoichiometry.

                    History

This observation was first made by theFrenchchemistJoseph Proust, based on several experiments conducted between 1798 and 1804.[2]Based on such observations, Proust made statements like this one, in 1806: