Observations of Chemical Reactions Are Summarized in Certain Generalizations Called the Laws of Chemical Change

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Observations of chemical reactions are summarized in certain generalizations called the laws of chemical change.  The three laws of chemical change are; 1)  Law of Conservation of Mass
2)  Law of Constant Composition
3)  Law of Multiple Proportions
Law of Conservation of Mass
* States that during a chemical reaction, matter is neither created or destroyed Mass of reactants = mass of products
Law of Constant Composition
* The percentage composition by mass in particular compounds never varies * In other words, in the formation of a compound, the mass of 1 element needed to combine with a given mass of another is always the same * E.g. 39.37% Na : 60.73% Cl for compound NaCl

Law of Multiple Proportions
* Atoms of 2 elements can combine in more than 1 way
e.g.   elements H & O can form water (H2O) and hydrogen peroxide                               (H2O2) —both have different physical and chemical properties despite containing the same atoms i.e. H2O2 bleaches most dyes while H2O does not * When the proportions (by mass) in which 2 elements combine to form 2 different compounds are divided by each other, the result is a fraction composed of small whole numbers Or in other words…..

* When 2 elements, A and B, form more than one compound, the mass of element A divided by the mass of element B in one compound, compared with mass of A divided by the mass of B in the second compound gives a ratio of small whole numbers

“EL FILIBUSTERISMO”

“NOLI ME TANGERE”

Ipinasa ni:
Patirck Jasper A.
Mendoza
III-SSC

John Lester D. Mones III-SSC

Aeron R. Mojica
III-SSC
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