CHEMICAL REACTION

CHEMICAL REACTION

        A chemical reaction is a natural process that always results in inter-change kimia.Senyawa compound or compounds early in the reaction is referred to as the reactants. Chemical reactions are usually characterized by a chemical change, and will produce one or more products that typically have characteristics that are different from the reactants. Classically, chemical reactions involve changes involving the movement of electrons in the forming and breaking of chemical bonds, although the general concept is basically a chemical reaction can also be applied to the transformation of elementary particles such as the nuclear reaction.

       Reactions with different chemical used in chemical synthesis to produce the desired compound. In biochemistry, series of chemical reactions catalyzed by enzymes form metabolic pathways, in which the synthesis and decomposition is usually not possible in the cell do.
 The reaction of two or more elements together results in the formation of chemical bonds between atoms and formation of chemical compounds (see Module Chemical Bonding us). But why chemicals react together? The reason has to do with the configuration of the atomic electrons participate '(see our Periodic Table of Elements module).
     In the late 1890s, Scottish chemist Sir William Ramsay discovered the element helium, neon, argon, krypton, and xenon. These elements, along with radon, placed in group VIIIA of the periodic table and called inert (or noble) gases because of their tendency to not react with other elements (see pages our periodic table). The tendency for the noble gases do not react with other elements to do with their electron configuration. All noble gases have a full valence shell, this configuration is a stable configuration and one of the other elements are trying to achieve by reacting together. In other words, the reason atoms react with each other is to reach a state where they are filled valence shell.
Let's look at the reaction of sodium with chlorine. In the countries of their atoms, sodium has one valence electron and chlorine has seven.sodium-E configuration with chlorineSodium Chlorine
Chlorine, with seven valence electrons, needs one extra electron to complete the valence shell with eight electrons. Sodium is a bit tricky. At first it seemed that the sodium needed seven additional electrons to complete its valence shell. But this will give sodium -7 electric charge and makes it very balanced in terms of the number of electrons (negative charge) relative to the number of protons (positive charge). Apparently, it is much easier to give the sodium valence electrons and become ions +1. Thus, the sodium atom emptying third electron shell and now the outer shell containing electrons, the second shell, filled - agrees with our previous statement that atoms react as they try to fill their valence shell.sodium chloride - Sodium Chloride
Sodium Chloride
This trait, the tendency to lose electrons when entering a chemical reaction, it is common for all metals. The number of electrons of metal atoms will lose (and they will take the charge) is equal to the number of electrons in the valence shell of atoms. For all the elements in Group A of the periodic table, the number of valence electrons is equal to the number of groups (see pages our periodic table).
Nonmetals, by comparison, tend to gain electrons (or share) to complete their valence shells. For all nonmetals except hydrogen and helium, they are complete with eight valence shell electrons. Therefore, nonmetals gain electrons in accordance with the formula = 8 - (group #). Chlorine, in a group of 7, will get 8-7 = 1 electron to form -1 ions.
Hydrogen and helium have only electron in their first electron shell. The capacity of this shell is two. So helium, with two electrons, already has a full valence shell and crashed into a group of elements that are less likely to react with others, noble gases. Hydrogen, with one valence electron, will gain one electron when forming negative ions. However, hydrogen and metalloid elements on the periodic table labeled, can actually be a positive or negative ions are formed in accordance with the number of valence electrons they have. So hydrogen will form +1 ions when it loses one electron and ion -1 when gains one electron.Reaction energy
All chemical reactions are accompanied by energy changes. Some reactions release energy to their surroundings (usually in the form of heat) and is called exothermic. For example, sodium and chlorine react so hard that the fire can be seen as an exothermic reaction give off heat. On the other hand, some reactions need to absorb heat from their environment to continue. These reactions are called endothermic. A good example of an endothermic reaction is occurring in an instant '"cold pack." Commercial cold packs usually consist of two compounds - urea and ammonium chloride in a separate container in a plastic bag. When the bag is bent and damaged containers in two compounds mix together and begin to react. Because endothermic, absorbing heat from the surrounding environment and the bags get cold.
The reaction was followed immediately when the two substances are mixed together (like the reaction of sodium with chlorine or urea with ammonium chloride) is called a spontaneous reaction. Not all reactions proceed spontaneously. For example, think about the game. When you strike a match you cause a reaction between the chemicals in the match head and the oxygen in the air. The match will not ignite spontaneously, though. You must first input of energy, called the activation energy of the reaction. In the case of a match, you supply the activation energy in the form of heat to light a match in the match, after activation energy is absorbed and the reaction starts, the reaction continues until you either extinguish the fire or you run out of material to react.