Law of Chemical Combinations

The law of conversation of mass may bechange in the mass of the substances being
demonstrated by the union of hydrogen (H2) andchanged. For example, in iron (Fe) increase in
oxygen (O2) to form water. If the H2 and O2weight on rusting in because of its combination
are weighted before they unite it will be foundwith oxygen from the air and the increase in
their combined weight is equal to the weight ofweight is exactly equal to the weight of oxygen
water (H2O) formed.combined. The French chemist Lavosier, (1785)
Chemistry deals with the matter and the changestired to learn about chemical changes by weighing
occurring in it, chemists are particularly interestedthe quantities of substances used in chemical
in these changes, where one or more substancesreaction. He found that when a chemical reaction
are changed in to quite different substances. Theywas carried out in a closed system, the total
had found that these chemical changes areweight of the system was not changed. The
governed by some empirical laws known as lawsmost important reaction that Lavosier performed
of chemical combinations.was the decomposition of the red oxide of
These laws are:mercury to from metallic mercury and and a gas,
1. Law of conservation of mass.he named this gas as oxygen. Lavosier
2. Law of constant composition (or) Law ofsummarised his finding by formulating a law, which
definite proportionsis known as law of conversation mass. It states
3. Law of multiple proportionsthat mass is neither created nor destroyed during
4. Law of reciprocal proportions.a reaction. In other words, in any chemical
Matter under goes changes. However, it has beenreaction the initial weight of reacting substances is
found that in all chemical changes, there is noequal to the final weight of the products.