using English the result of a chemical reaction

using english the result of a chemical reaction 

Chemical reaction is a process that always produce between chemical bahansenyawa. Compound or compounds early involved in the reaction is referred to as reactants. Chemical reactions are usually characterized by chemical changes, and will produce one or more products that typically have characteristics that are different from the reactants. Classically, chemical reactions involve changes that involve the movement of electrons in a chemical bond formation and termination, although basically the concept of common chemical reactions can also be applied on the transformation of the particles element as in the nuclear reaction.

Chemical reactions are used together in different chemical synthesis to produce the desired compound. In biochemistry, a series of chemical reactions that are dikatalis by enzymes form metabolic pathways, at which synthesis and decomposition which is normally not likely to occur in the cell do.

 

The chemical reaction is another term of chemical changes. In a chemical reaction, is always changing from the original substance (reactant or reactants) into a new substance (reaction results or product). In the process of brewing of cassava into tape, cassava and yeast is pereaksinya, while the tape was the product of the reaction. Apart from the occurrence of a new substance, chemical changes can still be distinguished from physical changes based on the traits that can accompany it.

There are four things that characterize or guidance has the chemical reaction, i.e.

1. The occurrence of a change in color

The color change occurs the existence of a chemical reaction that involves the process of changing the structure or the arrangement  .

Example: If we burn wood or paper, then paper or wood before and after it is burned will differ.

2. The occurrence of temperature changes

A chemical reaction can occur with an accompanying the release or absorption of heat. In a chemical reaction that took off the heat, the temperature of a substance reacts will increase, while the chemical reaction that accompanied the heat absorption can we know with a decrease in the temperature of a substance that reacts.

 

3. Formation of sediment

Deposition is a solid that does not dissolve in the liquid and formed from the reaction between two solution. The resulting precipitate in a chemical reaction, usually have a specific color. The color of the sediment is not always the same as the color of the substances that react and not all chemical reactions between two solution can result in deposition. Substances soluble in water typically has a great tendency to form sediment than substance soluble. Some chemical substances which are soluble in water i.e. AgCl, PbCl2, PbI2, BaSO4, PbSO4, CaCO3 and much more. If the two pieces of the solution is reacted and the resulting reactions from substances which are soluble in water, then most likely it will precipitate out.

4. the gas is formed

As with the sediment, in chemical reactions can also be produced gas. The resulting gas can form hydrogen gas, oxygen, carbon dioxide, or other gases. The formation of gas from a chemical reaction are characterized by the presence of bubbles of gas, the smell or other characteristics.

Corrosion in metals results from interaction between the metals and the environment that are corrosive, humid environments i.e. (containing water vapor) and induced by the presence of O2, CO2, gas or H2S. Corrosion can also occur due to high temperature. Corrosion on metals can also be viewed as the process returns to its original state of metal, namely metal ores. For example, corrosion on the iron becomes iron oxide or iron carbonate.

4fe (s) + 3O2 (g) + 2nH2O (l) → 2Fe2O3. nH2O (s)

Fe (s) + CO2 (g) + H2O (l) → Fe2CO3 (s) + H2 (g)

Because corrosion can change the structure and properties of metal corrosion then tends to be detrimental. Approximately 20% of metal damaged by corrode on each year.

Because iron is the main ingredient for a variety of construction then the corrosion control becomes very important. To be able to control the corrosion of course have to understand how the mechanisms of corrosion in steel. Corrosion electrochemical process belongs to, as shown in Figure 1.

The iron has a surface not smooth due to the imperfect composition, also due to the difference in surface tension that creates potential on certain areas higher than other areas. In the area of anodik (the surface area in contact with the water) occurs dissolving iron atoms accompanied the release of electrons to form Fe2 + ions are soluble in water.

Fe (s) → Fe2 + (aq) + 2e –

The electrons flow through the iron is released, as electrons flow through an external circuit in the volta cell cathodic areas to happen toward the reduction of oxygen gas from the air:

O2 (g) + 2H2O (g) + 2e – → 4OH-(aq)

Fe2 + ions are soluble in water droplets move towards area as cathodic ions pass through the salt bridge in volta cell and reacts with OH ions – form Fe (OH) 2. Fe (OH) 2 is formed is oxidized by oxygen to form rust.

FE2 + (aq) + 4OH-(aq) → Fe (OH) 2 (s)

2Fe (OH) 2 (s) + O2 (g) → Fe2O3. nH2O (s)

The overall reaction on corrosion of iron are as follows (see the mechanism in Figure 2):

4fe (s) + 3O2 (g) n + H2O (l)→2Fe2O3. nH2O (s)

Due to the migration of ions and electrons, rust is often formed in the area some distance from the surface of the iron that corrode (holes). The color of rust on a variety ranging from yellow to red-brown and even black. The color depends on the amount of H2O molecules bound to rust.

The iron has a surface not smooth due to the imperfect composition, also due to the difference in surface tension that creates potential on certain areas higher than other areas. In the area of anodik (the surface area in contact with the water) occurs dissolving iron atoms accompanied the release of electrons to form Fe2 + ions are soluble in water.

Fe (s) → Fe2 + (aq) + 2e –

The electrons flow through the iron is released, as electrons flow through an external circuit in the volta cell cathodic areas to happen toward the reduction of oxygen gas from the air:

O2 (g) + 2H2O (g) + 2e – → 4OH-(aq)

Fe2 + ions are soluble in water droplets move towards area as cathodic ions pass through the salt bridge in volta cell and reacts with OH ions – form Fe (OH) 2. Fe (OH) 2 is formed is oxidized by oxygen to form rust.

FE2 + (aq) + 4OH-(aq) → Fe (OH) 2 (s)

2Fe (OH) 2 (s) + O2 (g) → Fe2O3. nH2O (s)

The overall reaction on corrosion of iron are as follows (see the mechanism in Figure 2):

4fe (s) + 3O2 (g) n + H2O (l)→2Fe2O3. nH2O (s)

Due to the migration of ions and electrons, rust is often formed in the area some distance from the surface of the iron that corrode (holes). The color of rust on a variety ranging from yellow to red-brown and even black. The color depends on the amount of H2O molecules bound to rust.