384866998-Hukum-hukum-Dasar-Kimia.txt - The Fundamental...

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The Fundamental Laws of Chemistry As we have discussed, matter can be classified into different categories ba sed on directly observable properties, be they physical or chemical. Heterogeneous systems contain multiple phases and can be separated using fairl y standard techniques (e.g., filtration, separatory funnel, etc.) into a series of homogene ous systems. These homogeneous systems can be further classified according to whether they are solutions, containing multiple components, or pure substances. Solutions, themselves, can be further separated into their constituent components, although the techniques to achieve this separation (e.g., distillation, chromatography) are somewhat more complex than those required to separate heterogeneous systems. Pure Substances fall into one of two categories; those which are compounds and those which are elements. Compounds can be broken-down via some standard physical or chemical method, elemental substances cannot. This level of "separation" is significantly more difficult than required of the previous two levels of separation. Lavoisier used strong heating in the presence of Iron to break-down Water, and, thus, demonstrate its compound nature. Water can also be broken-down using electrolysis, where it is decompos ed directly into hydrogen and oxygen gases. It has been found there are ~115 chemically elemental substances; each represented in the Periodic Table of the Elements. At this point, we wish to consider the "rules," or Natural Laws, governing the reconstruction of Compounds from the Elements. These are the Fundamental Laws of Chemistry. Recall, Laws of Nature are broad statements to which there are no exceptions. The Laws we will discuss are the Fundamental Laws on which the science of chemistry is built . The central question we wish to answer is, how can such a limited number of elemental substances be combined such as to form the ~15 million known compounds? For concreteness, consider the combination of elemental Carbon and elemental Oxygen by direct chemical reaction. If the reaction is carried out in an excess of oxygen, in other words, in a furnace with adequate ventilation, the compound Carbonic Acid is formed: On the other hand, if the oxygen is fed into the furnace in limited amounts, via a Regulator , the compound Carbonic Oxide is formed: How do we know these gaseous products are indeed different compounds? The intensive physical properties of each gas are distinct: Carbonic Acid Carbonic Oxide Colorless Colorless Odorless Odorless sublimation pt. = -78o C melting pt. = -205oC boiling pt. = -191oC Soluble in Water Insoluble in Water Non-Combustible Combustible
Now, back to the question posed above. How can these two elements form two different compounds? The Fundamental Laws of Chemistry will provide an answer to this question.

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