CHEMICAL REACTION

CHEMICAL REACTION

A chemical reaction is a natural process that always produces antarubahan chemical compounds. 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. 

CHEMICAL REACTION EQUALIZATION
 The basis for equalizing the chemical reaction is the law of mass eternity filed by Lavoiser, and stated "In a reaction, the mass of substances before reacting equal to the mass of the substance after reacting". This suggests to us that there is no mass loss during the ongoing reaction.In a chemical equation, there are two areas, the area where the substance before reacting to the left of the arrow and the area where the substance has reacted in the right arrows.In both these areas, we will get the information that the substances before and after the reaction is the same, the same can be shown to equal the number of atoms, or the number of masses. The example below can explain what information we can from the equationC + O2 → CO2This equation is true if the number of carbon atoms on the left arrow (before reaction) equal to the number of atoms right arrows (after reaction). Similarly, the oxygen atom before and after the reaction is the same.It appears that the number of C atoms on the left and right are the same, as many as 1 piece. Similarly, for the same number of O atoms is 2 pieces. Thus the equation is correct.Other information is the amount of Carbon and Oxygen mass before and after the reaction is the same, for example, there are 12 grams of carbon and 32 grams of oxygen before reacting, based on the equality of the number of atoms of the same, then automatically the amount of a substance that occurs has the same mass composition. CO2 compounds, containing 12 grams 32 grams C and O.Generally rudimentary written equation, where the number of atoms before and after the reaction has not been the same as:N2 + H2 → NH3The number of atoms N as left arrows 1 piece, right arrows 1 piece, so that the arrows on the right multiplied by 2. As a result of multiplying the number of H atoms next to it into 6 pieces, while on the left there are 2 pieces. To balance the H atom, the H atom left multiplied by 3. Figures multiplier used to menyetarakanan reaction, then entered into the equation. 

GROUPING CHEMICAL REACTION
 The diversity of chemical reactions and approaches taken in the study resulted in many ways to classify these reactions, which often overlap. Below are examples of classification of chemical reactions that are normally used.Four basic reaction 
Synthesis 
In direct combination or synthesis reaction, two or more simple compounds combine to form a new, more complex compound. Two or more reactants react to produce a product that is also one way to find out if it is the synthesis reaction. An example of this is the reaction of hydrogen gas with oxygen gas combine the result is water.Another example is nitrogen gas combine with hydrogen gas to form ammonia, by the equation:N2 + 3 H2 → 2 NH3 
Dekomposisisi 
Decomposition reaction is the opposite of analysis or synthesis reactions. A more complex compounds are broken down into simpler compounds. Examples are water molecules are split into hydrogen gas and oxygen gas, with the equation:2 H2O → 2 H2 + O2 
Single replacement 
In a single replacement or substitution reaction, a single element of a single element replaces another in a compound. Examples are sodium metal reacts with hydrochloric acid will produce sodium chloride or table salt, the reaction persamaaan:2 Na (s) + 2 HCl (aq) → 2 NaCl (aq) + H2 (g) 
Replacement double 
In a double replacement reaction, two compounds or ions change each bond to form new compounds are different. This occurs when the cations and anions of two different compounds each move, and form two new compounds. The general formula of this reaction is:AB + CD → AD + CBAn example of a double replacement reaction is lead (II) nitrate reacts with potassium iodide to form lead (II) iodide and potassium nitrate, with the equation:Pb (NO3) 2 + 2 KI → PbI2 + 2 KNO3Another example is sodium chloride (table salt) reacts with silver nitrate to form sodium nitrate and silver chloride, the reaction equation:NaCl (aq) + AgNO3 (aq) → NaNO3 (aq) + AgCl (s) 

CHARACTERISTICS OF CHEMICAL REACTION 
1. Colour Change Happen In a chemical reaction, reactants are converted into products. Changes may occur due to the termination of the bonds of the reactants and the formation antaratom ties bru that make up the product. Energy required to break the tie. To form a new bond, released some energy. Thus, the chemical reaction energy changes.Chemical reactions that produce energy in the form of heat is called exothermic reactions. Reactions that absorb heat energy called endothermic reactions.Example: Fire can warm up a cold and when hot breath in the body due to exercise so that the body becomes cold expelled.
2. Temperature changes occurIn a chemical reaction, reactants are converted into products. Changes may occur due to the termination of ties antaratom reagents and formation of new bonds that make up the product. Energy required to break the tie.Chemical reactions that produce energy in the form of heat is called exothermic reaction, while the reaction absorbs heat energy called endothermic reactions.A chemical reaction occurs in a space that we call dbngan system, places outside the system is called the surroundings.In exothermic reactions, heat transfer occurs from sisitem to the environment.In endothermic reactions occur transfer heat energy from the environment to the system.
3. Sediment formation occursWhen two solutions react in a test tube, sometimes forming an insoluble sneyawa, solid, and separated from the solution. The solid is called the precipitate (precipitate)
4. Gas Formation occursSimply put, the chemical reaction created a gas which indicated the presence of bubbles in solution reacted. The gas can be determined from the typical smell, like sour sulfide (H2S) and ammonia (NH3), which stinks.