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OXYGEN AND NITROGEN

Nitrogen is present in the earth's atmosphere in the greatest number reaching 78%. In nature, nitrogen is not as a free element, but forming a colorless and odorless diatom gas with the N2 molecule formula.

Nitrogen or lymph is a chemical element in the periodic table that has the N symbol and the atomic number 7. This is the lightest technique at room temperature. Usually found as a colorless gas, odorless, tasteless, and a diatomic gas, it is very difficult to react with other elements or compounds. Named a limp because this substance is lazy, inactive reacts with other elements. Nitrogen is a common element in the universe, thought to be the seventh element of total abundance in the Milky Way and the Solar System. On Earth, this element makes up about 78% of the Earth's atmosphere and is thus the most abundant free element. The nitrogen element was discovered as a component that could be separated from the air, by Scottish physicist Daniel Rutherford, in 1772.

In addition to filling 78.08 percent of Earth's atmosphere, nitrogen is present in many living tissues. Substances form many important compounds such as amino acids, ammonia, nitric acid, and cyanide.

The role of nitrogen in the industry is relatively large, and industries that use nitrogen as the basic ingredient are also referred to as the nitrogen industry. Air-derived nitrogen is a major component of fertilizer manufacturing and has greatly assisted in the intensification of food production worldwide. The development of the nitrogen fixation process has succeeded in clarifying the various principles of chemical processes, and high pressure processes and has contributed much to the development of chemical engineering.

Prior to the synthetic nitrogen fixation process, the main source of nitrogen for agricultural purposes is only waste material, and animal waste, the decomposition of these materials and ammonium sulphate obtained from the by-products of coking from coal. Materials such as these are not easily handled not to mention the insufficient amount of all the necessary needs.

Chilean salpeter, salpeter from animal urine, and humans, and ammonia collected from coke making have become important these days but are ultimately set aside again by synthetic ammonia, and nitrates. Ammonia is the base material for the manufacture of almost all types of products that use nitrogen.

HISTORY OF OXYGEN

Oxygen (O2) is the 3rd most abundant chemical element on earth. Oxygen is often called diatomic gas compound with the formula O2 is colorless, tasteless, and odorless. Diatomic oxygen gas fills 20.9% of the Earth's atmospheric volume, oxygen or acidic substances as well as parts of Chemistry. The oxygen in the order of the periodic table is at atomic number 8, is a catalytic element and can easily react with almost any other element. Oxygen separately was discovered by Carl Wilhelm Scheele at Uppsala in 1773 and Joseph Priestley in Wiltshire in 1774.

Priestley's findings are more famous because the publications are the first printed. In his findings Joseph Priestley directs sunlight on mercury (II) oxide so that it breaks down into mercury and oxygen gas. Priestley found that the candle flame was brighter in Oxygen gas than in ordinary air. Shortly after this discovery, Lavoiser discovered that the increasing mass of metal burned in the air is nothing else because it binds Oxygen. The name Oxygen itself is given by Lavoiser on the assumption that the element is present in all acids (Oxygen: acid-forming).

Research Articles On Chemistry Laerning

Harmful chemicals '' sulfuric acid ''

              Sulfuric acid or sulfuric acid is a strong acid with high corrosive properties. Sulfuric acid is easily soluble in water in various comparisons. Sulfuric acid is very dangerous when exposed to skin tissue due to its corrosive nature, with its corrosive nature will cause injuries like burns. The higher the concentration of sulfuric acid the greater the danger

Potential hazard : 

The corrosive sulfuric acid properties are exacerbated by its exothermic reaction with water. Burns due to sulfuric acid are potentially worse than burns due to other strong acids, this is due to additional tissue damage due to dehydration and thermal damage secondary to the release of heat by the reaction of sulfuric acid with water. In addition, concentrated sulfuric acid or commonly called oleum is dangerous. Oleum will produce highly reactive SO2 gas which, if inhaled, will damage the lungs. For first aid if inhaled, seek fresh air immediately and seek medical advice.

Steps to be taken if exposed to sulfuric acid are, flush parts of the body exposed to sulfuric acid with water flowing for 10-15 minutes. Examples of sulfuric acid burning skin It aims to cool the tissue around the acid burns, and to prevent secondary damage. Clothes exposed to sulfuric acid should also be released immediately, and flush with water exposed skin sulfuric acid through the clothes.If exposed to sulfuric acid in the eyes, immediately flush your eyes with warm water for 20 minutes, and immediately go to the doctor. 

Prudence is essential in dealing with sulfuric acid. It is advisable to use security equipment Essentially, sulfuric acid itself is one of the main ingredients in a wide variety of chemical industries. Some chemical industries that utilize sulfuric acid chemicals include the processing of chemical synthesis, mineral ores, oil refineries, and are also often used for wastewater treatment.

Although it has many benefits, especially in the chemical industry, sulfuric acid or H2SO4 is one type of harmful chemical compounds and belongs to a group of harsh and corrosive chemicals. Making direct contact with these sulfuric acid chemicals can cause various health problems in our body. What are the dangers of exposure to sulfuric acid? Here are some of them:

A. Pain in the skin

Having direct contact with sulfuric acid in small amounts, such as accidental exposure to droplets from sulfuric acid in very small amounts can cause the skin to feel very sore and sore. This is the same as what we feel when we are in contact with other hard acidic compounds, such as caustic soda, commonly used to fade paint. This pain usually feels like being pierced by a very sharp needle, and will last long enough, but will soon subside after washing with clean running water.

A number of other things that can cause skin irritation condition are:

a.side effect of eyebrow embroidery

b. the danger of liposuction

c. the dangers of skinny pants

2. Skin that burns

       Other hazards when the skin and also our body are in direct contact with sulfuric acid in the absence of a safety device is that it can cause heat and burning sensation on the skin. This happens when we make direct contact with sulfuric acid in greater quantities, more than one drop. Usually the burning and burning sensation will last very long, and has a much higher pain intensity, than when we just get a little bit of it.

To overcome it, still the same as before, that is by washing the skin affected by sulfuric acid by using clean running water.

Other conditions that can cause skin burn is due to:

• the dangers of mosquito coils

• the danger of ultraviolet light

• too many x-rays

3. Peeling skin

The dangerous effect of sulfuric acid that you should notice is that it can damage skin tissue and make skin peel. This happens when you are in contact with a very large amount of sulfuric acid. Several cases have been revealed, where an act of crime is done by pouring sulfuric acid to the victim.

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Exposed to sulfuric acid in large quantities, even almost all parts of the body will make the network of skin cells become damaged and also die. This will impact on the exfoliation of the skin, which causes the skin as burned out by a very great fire. Plastic and other healing operations are medically very, very, very necessary to overcome the adverse effects of sulfuric acid in large quantities, which affect the exfoliation of the skin.

Here are some conditions that result in exfoliation of the skin: • dirty blood symptoms • causes of skin allergies • danger of bathing in a public swimming pool 4. If exposed to eyes, may cause irritation Not only exposed to sulfuric acid directly, but also aerosol alias steam from sulfuric acid is also very dangerous. When the aerosol from sulfuric acid is exposed to the eye, this will cause irritation to the eye and may cause the eye to become very sore and sore. Long-term effects are the eyes become red and may decrease from the ability of vision. How to prevent it, if our eyes are exposed to steam or aerosols from sulfuric acid is to directly clean the maata by using clean running water. Causes of eye irritation can also be caused by: • the danger of rubbing the eyes • the dangers of mosquito coils • the dangers of passive smoking 5. Causes respiratory problems Sponsors Link Aerosols or vapors from sulfuric acid not only give harmful effects to the eyes and skin, but also have adverse effects as well as harm to your breathing. Yes, the aerosols or vapors of the inhaled sulfuric acid will cause the appearance of respiratory distress. This can be a cause of chest shortness of breath and is not likely to have infections and also irritation of the respiratory organs such as the lungs.

Respiratory disorders are also caused by several conditions such as: • dangers of smoking • the danger of obesity • consumption of analgesic drugs Prioritize your safety if you have to do work that allows exposure to sulfuric acid. Use standardized rubber gloves, as well as laboratory glasses and also use a mask to prevent air or vapor from sulfuric acid from being inhaled.

Other Sulfuric Acid Hazards

In addition to harm to the health of the body, there are at least two other harmful effects of sulfuric acid. Here is another danger of sulfuric acid:

A. May cause fire

Sulfuric acid that is not stored properly and properly will cause a great fire. Therefore, the storage of these chemicals and other types of chemicals should follow the procedure. The sure thing is to stay away from sources of fire and also excessive heat, and store in a secure closed container from the hands is not responsible.

B. Can cause rust on iron

The hazard effect exposed to sulfuric acid can also lead to the appearance of rust on iron, so it is advisable to avoid and also keep these chemicals away from non-stainlees.

These are some of the dangerous effects of sulfuric acid. Hopefully this article can add insight to you all and hopefully you are more careful in making contact with dangerous chemicals.

Using english to show cause and effect

Show cause and effect

For it is a matter expressed in order to establish a factual opinion which then actually occurs
Something which is the end or result of an event (deed, decision); Requirements or circumstances preceding it

Chemical change is a change that produces new substances. New substances produced there are those who can return to their original form and some are not able.

• Causes of chemical reactions:

1. Occurs due to burning.

2. Occurs due to mixing of substances.

3. Occurs due to the flow of electricity.

The chemical reaction equation is written as follows:

A and B reactants

C and D reaction products.

In the reaction equation there is a symbol of the form of substance: s (solid), aq (aqueous), l (liquid) and g (gas).

• Characteristics of chemical reactions:

A. Making gas

B. Formation of precipitate

C. Discoloration

D. Temperature changes

• Various kinds of chemical reactions:

1. Decomposition

2. Oxidation

3. Reduction

4. Neutralization

5. Precipitation

6. Exchange

7. Fermentation

• How to control the speed of the reaction can be done by changing:

A. Reaction temperature

B. Concentrations of reagents

C. Touch surface area

D. Catalyst

C. Chemical Reactions in Everyday Life

1. Corrosion

2. Decomposition of food

3. Fireworks

• Division of Material Nature

Based on the ability of substance

1. Physical properties: properties that can be observed without changing the identity of the substance.

Example: melting point, boiling point, heat conductivity, electric conductivity, density, hardness level etc.

2. Chemical properties: properties related to the ability of the substance to react to form other substances.

Example: the ability of a substance to react with oxygen, water, acid etc.

 Decay

       If food and drink are left too long, after a certain period of time the food and beverages will decay which is usually characterized by a change in appearance, such as discoloration and the appearance of a foul odor. The emergence of discoloration and foul smell indicates that there are new substances that were not present in the food and drink. Thus, decay is one example of chemical change

Unprocessed foods will worsen, when stored and consequently ingested. Butter, cheese, bacon, dried fruits and some traditional food products are derived from various processing processes to make excessive use of food. Regardless of the conversion from food examination to a more permanent form, however, a large amount of food is still losing every year as a consequence Of various types of food rot. It has been estimated that between 10 and 20 percent more food has been fully available if the mushrooms can be completely prevented.

Drying, decomposition, contamination with dirt from chemicals and damage by animals or insect pests occur when they all become part of food rot. In many cases, this short decay can be avoided if care is taken in transporting and storing food. The occurrence of unwanted chemical reactions, such as oxidation, also causes decay. The most important cause of food decay, however, is the attack of micro-organisms with or Such as yeasts and bacteria.

CORROSION

In general, corrosion is the destruction of metal objects due to environmental influences. The corrosion process can be explained electrochemically, for example in the process of ironing which forms iron oxide (F2O3.nH2O). Electrochemically, the process of ironing is an iron oxidation event of iron by oxygen from the air.

A. CORROSION OF DEFINITION

 Corrosion in iron due to conta with water. In the iron there is anode and there is a cathode.

Anode: Fe (s) → Fe2 + (aq) + 2e- Eo = +0,44 V

Codes: O2 (g) + 2H2O (l) + 4e- → 4OH- (aq) Eo = +0.40

---------------------------------- +

Cell reaction: 2Fe (s) + O2 (g) + 2H2O (l) → 2Fe2 + (aq) + 4OH- (aq) Eo = +0.84 V

The Fe2 + ion then undergoes further oxidation by reaction:

4Fe2 + (aq) + O2 (g) + (4 + 2n) H2O (l) → 2Fe2O3.nH2O + 8H + (aq)

Based on the potential value of the reaction, iron is an easily corrosive metal. Other metals with electrode potential values ​​greater than 0.4 V will be difficult to corrosive, since they will produce Eoreact <0 (negative) when in contact with oxygen in the air. The metals of silver, platinum, and gold have electrode potentials greater than 0.4 V so it is difficult to experience corrosion.

B. CORROSION / CORROSTING CAUSE FACTORS

1. Water and air humidity Judging from the reaction that occurs in the corrosion process, water is one important factor for the ongoing corrosion. Humid air that contains moisture will accelerate the process of corrosion.

2. Electrolyte Electrolyte (acid or salt) is a good medium for the transfer of charge. This results in the electrons being more easily attached to the oxygen in the air. Rain water contains acid, while salt water contains salt. Therefore rainwater and seawater are the main causes of corrosion. 3. Uneven metal surfaces Uneven metal surfaces facilitate the occurrence of poles of charge, which will eventually act as anode and cathode. Smooth and clean metal surfaces will cause difficult corrosion, because the poles that will act as anode and cathode are difficult to form.

4. The formation of electrochemical cells If two different metals are potentially tangent to the aqueous or moist environment, electrochemical cells may form directly. The lower potential metal will immediately release the electrons when in contact with a higher potential metal and will be oxidized by oxygen (O2) from the air. This results in faster corrosion occurring in potentially low metals, while potentially high metals are even more durable. For example, a rivet made of copper to connect iron would cause the iron around the rivet to rust more quickly.

 

C. HOW TO PREVENT CORROSIONS Corrosion events are difficult to prevent, but can be inhibited in the following ways: 1. Controlling the atmosphere to keep it from moisture and plenty of oxygen, for example by making the air environment free of oxygen by passing CO2 gas. 2. Prevent metals intersect with oxygen in the air as well as water. Prevention is done in the following way. A. Paint it The paint layer prevents direct iron contact with oxygen and water. Only if the paint is scratched or peeling, then corrosion begins to occur and can spread under the paint that is still intact. Examples that use this technique are on boats, bridges and cars. B. Gives oil, oil or fat The oil and grease layers prevent direct contact of iron with oxygen and water and should be applied periodically. Examples that use this technique are on the moving parts of the machine, like a car engine. C. Gives a plastic coating The plastic layer prevents direct iron contact with oxygen and water. Only if the plastic is peeling off, corrosion begins to occur. Examples that use this technique are on kitchen items, such as dryer racks.

The neutralization reaction is a reaction in which acids and bases react in an aqueous solution to produce salt and water. The liquid sodium chloride produced in the reaction is called salt. A salt is an ionic compound comprising a cation of a base and an anion of an acid. A salt is essentially any ionic compound that is neither an acid nor a base.

C. Reaction of Strong-Acidic Acid

When equal amounts of strong acids such as hydrochloric acid are mixed with strong bases such as sodium hydroxide, the result is a neutral solution. The reaction product does not have either acidic or alkaline characteristics. Here is the equation of the molecular balance reaction.

HCl (aq) + NaOH (aq) → NaCl (aq) + H2O (l)

The chemical reaction occurring in a water solution is more accurately represented by the net ion ion equation. The complete ionic equation for neutralizing hydrochloric acid with sodium hydroxide is written as follows:

H + + Cl- + Na + + OH- → Na + + Cl- + H2O

Since both acid and base are strong, they are fully ionized and so on written as ions, as NaCl is formed as a product. Sodium ions and chloride ions are the spectator ions in the reaction, thus producing the following reskai as a clean ionic reaction.

H + + OH- → H2O

All strong acid neutralization reactions with strong bases are clean ionic reactions of hydrogen ions combined with hydroxide ions to produce water.

What if the acid is a diprotic acid such as sulfuric acid? The equilibrium equation of molecules now involves a ratio of 1: 2 between acid and base.

H2SO4 (aq) + 2NaOH (aq) → Na2SO4 + 2H2O (l)

In order for the reaction to be fully neutralized, twice as much NaOH mole should react with H2SO4. The soluble sodium sulfate salt, and so on the same clean ionic reactions. Different mole ratios occur due to other polyprotic acids or bases with some hydroxides such as Ca (OH) 2.

D. Fermentation is the process of energy production in cells in anaerobic state (without oxygen). In general, fermentation is one form of anaerobic respiration, however, there is a clearer definition that defines fermentation as respiration in an anaerobic environment with no external electron acceptor.

Sugar is a common ingredient in fermentation. Some examples of fermented products are ethanol, lactic acid, and hydrogen. However, some other components may also be produced from fermentation such as butyric acid and acetone. Yeast is known as a material commonly used in fermentation to produce ethanol in beer, wine and other alcoholic beverages. Anaerobic respiration in the mammalian muscle during hard work (which has no external electron acceptor), can be categorized as a form of fermentation that produces lactic acid as a by-product. Accumulation of lactic acid is what plays a role in causing fatigue in the muscle.

. Alcohol fermentation

Alcohol fermentation is a reaction of conversion of glucose to ethanol (ethyl alcohol) and carbon dioxide. Organisms that play the role of Saccharomyces cerevisiae (yeast) for the manufacture of tape, bread or liquor. Chemical reaction:

C6H12O6 → 2C2H5OH + 2CO2 + 2 ATP

2. Fermentation of lactic acid

Lactic acid fermentation is a respiration that occurs in animal or human cells, when oxygen demand is inadequate due to overwork

Inside the lactic acid muscle cells can cause symptoms of cramps and fatigue. Lactates that accumulate as waste products can cause tired and painful muscles, but are slowly transported by blood to the liver to be converted back into pyruvate. Glucose is broken down into 2 pyruvic acid molecules through glycolysis, forming 2 ATP and 2 NADH.

3 Vinegar fermentation

It is an example of a fermentation that takes place in aerobic state. This fermentation is done by acetic acid bacteria (acetobacter aceti) with ethanol substrate. The energy produced is 5 times greater than the energy produced by anaerobic alcoholic fermentation.

Using english to Compare the element

The Elemennt

Any element or compound contained in the sea or in air has distinctive properties that are different from other elements or compounds. Trends that occur due to the physical and chemical properties between elements in a group or period table

1. Understanding the elements

The element is a single substance that can not be decomposed into other substances simpler through ordinary chemical reactions. The smallest part of an element is an atom. Some examples of elements are gold, silver, aluminum, copper, sulfur, carbon, and so on. Up to now has been known for more than 112 elements, was found in a free state, such as gold and diamonds, but most of the elements found in a bound state as a compound. Elements can be grouped into metals, non-metals, and metalloids / metal.

2. The element emblem

To simplify the name of the element, the scientists provide the element symbol. Coat of elements used until now made by Jons Jacob Berzelius. Here is a way of writing the symbol of the elements proposed by Jons Jacob Berzallius.

Is a chemical element that can not be subdivided into smaller substance, or can not be converted into other chemical substances using ordinary chemical methods. The smallest particle of an element is an atom. An atom consists of a nucleus of an atom (nucleus) surrounded by electrons. Atom consists of a nucleus of protons and neutrons. Until now there are approximately 117 known elements in the world.

The chemical compound is a single substance which is formed of several elements by chemical reaction and these compounds can also be broken down into its constituent elements by the chemical reaction. For example, dihydrogen monoxide (water, H2O) is a compound composed of two hydrogen atoms for every oxygen atom.

In general, this fixed ratio must be fixed due to the nature of physics, not a selected ratio of men. Therefore, materials such as brass, the superconductor YBCO, the semiconductor &aluminum gallium arsenide&, or chocolate are considered mixtures or alloys rather than compounds.

The characteristics that distinguish compound is that it has a chemical formula. The chemical formula gives the ratio of atoms in a substance, and the number of atoms in a single molecule (thus the formula for ethene is C2H4 and not CH2. The formula does not mention whether the compound is composed of molecules; for example, sodium chloride (common salt, NaCl is an ionic compound ,

The compound can form in several phases. Most of the compounds can be in the form of solids. Molecular compound may also be a liquid or a gas. All compounds will decompose to smaller compounds or individual atoms if heated to a certain temperature (called the decomposition temperature).

A. Halogen

a. Halogen Chemical Properties

1) Halogen is highly reactive groups in accepting electrons and acts as a strong oxidizing agent in one group. Growing up, the stronger the oxidizing agent.

2) halogen Electronegativities the Group increasingly greater upward. The most electronegative element than any other element in the periodic system is fluorine (note the data electronegativity).

3) The radius of the halogen atom in the group getting to the top of the smaller (note data). This means getting to the top of the smaller molecular size, then the attractive force between molecules (Van der Waals forces) will become smaller. Note also the boiling point and melting point, the more up vanishingly small.

Noble gas elements in the periodic system occupies a Group VIII A of the element Helium (He), Neon (Ne), Argon (Ar), krypton (Kr), Xenon (Xe) and radon (Rn). The structure of the outer electron octet noble gas (8) (except helium duplet (2)) is the most stable structure, therefore it is difficult noble gases react with other elements, so-called inert gas (slow). In 1962 Neil Bartlett succeeded in synthesizing a noble gas compound that is XePtF6. In the short time that other chemists showed that xenon can react directly with Fluor forming XeF2, XeF4, and XeF6. Since then the term inert is no longer appropriate and chemists began referring to the group of noble gases.

Alkaline earth metal element (IIA) is composed of Be, Mg, Ca, Sr, Ba, and Ra. This class has properties similar to the class IA. The difference is that it has a group IIA ns2 electron configuration and is a strong reducing agent. Although tougher than class IA, class IIA but is still relatively soft, shiny silver, and has a melting point and a higher density.

The elements in the third period consists of metal elements (Na, Mg, Al), metalloids (Si), non-metallic (P, S, Cl), and a rare gas (Ar). Electronegativities elements of the third period the greater the further right due to their atomic radius which is getting to the right is getting smaller. Antaratom in metal bonding strength increases (from Na to Al). This relates to the gain valence electrons. Silicon is a semiconductor / insulator because

including metalloid. This element has a very large covalent bonds, as well as phosphorus, sulfur, and chlorine which is an insulator because it includes non-metals (Source: http: //www.chem-is-try.org).

1. Nature of Transition Metals

All the elements of the transition is a metal, which is a soft, shiny, and electrically and heat. Silver is a transition element that has the highest electrical conductivity at room temperature and copper in second place. Compared with class IA and IIA, transition metal elements harder, has a melting point, boiling point, and higher density. This is because the transition elements share electrons in the skin d and s, so the bond is getting stronger.

2. Oxidation Numbers

Unlike class IA and IIA only has the oxidation number of +1 and +2, transition metal elements have several oxidation numbers. As vanadium has the oxidation number of +2, +3, and +4.

3. Nature of Magnetism

Every atom and molecule has magnetic properties, that is paramagnetic, in which atoms, molecules, or ions bit can be pulled by magnetic fields because there is an unpaired electron in the orbital and diamagnetic, in which atoms, molecules, or ions can be rejected by a magnetic field because all electrons in orbit in pairs. While in general the transition elements are paramagnetic because they have unpaired electrons in the d orbitals her. Paramagnetic properties of this would be stronger if the number of unpaired electrons in the orbital more. Metals Sc, Ti, V, Cr, and Mn is paramagnetic, while Cu and Zn is diamagnetic. For Fe, Co, and Ni are ferromagnetic, ie the same conditions as paramagnetic only in the solid state.

4. Ion Color

The energy levels of electrons in the transition elements are almost the same cause of color in transition metal ions. This happens because electrons can move to a higher level by absorbing visible light. In the transition class, the 3d subshell is not fully charged causes the electrons in the subshell it absorbs light energy, so that electrons are excited and emit light energy with a color that matches the color of light that can be reflected upon returning to the ground state. For example, purple Ti2 +, Ti4 + colorless, pink Co2 +, Co3 + blue, and so forth.

Using english to Classify matter

The composition of matter in chemistry

Each material consists of small grains or particles. Particles are the smallest part of matter that still has the same properties with the material.

Basic postulates of Dalton's atomic theory:

1. Any material consists of particles called atoms.

2. The element is composed of similar material atoms.

3. Atoms of an element are identical but different from the atoms of other elements.

4. The compound is a material consisting of two or more kinds of atoms with a fixed ratio.

5. Atoms can not be destroyed or created and can not be converted to another atom through a chemical reaction. Chemical reactions are rearrangement of atoms.

Objects that are frequently encountered in everyday life such as television, telephone, computer, and also watches everything including material. The atom is the basic constituents of matter that is invisible to our eyes. In every atom nuclei are composed of protons and neutrons cedar. Atomic nucleus surrounded by electrons speeding.

   1.  ATOM is the smallest part of an element that still has the properties of elements. The smallest part of a compound which still has the properties of compounds called molecules or ions. Molecule is a combination of two or more atoms (either similar or different types) are neutral. If an aggregate of atoms of the same type as it is called Molecular Elements, for example: O2, H2, O3, S8. If an aggregate of atoms of different elements kind then called Molecule Compounds, for example: H2O, CO2, C2H5

          2. ELEMENTS is a particle that could be the atomic / molecular elements. The elements of the particles in the form of atoms, that means that it can stand alone or simply contains one atom, the writing written with the chemical symbol, such as C (carbon), He (Helium). When the particle form of the molecule it means that these elements formed from a combination of atoms the same type, he can not stand on its own, the elements are written with a chemical symbol is accompanied by the number of constituent atoms. For example: O2, H2. Thus the oxygen element is never written only the letter O alone, but added the number 2 as meaning that the element is formed of two atoms of oxygen.

 NATURE ELEMENT

 Until now it has known no less than 114 kinds of elements consisting of 92 elements of natural and artificial elements 22. By its nature, the elements can be classified into metals, non-metals and metal elements. Examples of the metal elements of which are iron, zinc, and copper. Examples of non-metals of which are carbon, nitrogen, and oxygen. Silicon and germanium classified as metal. Try to look for some examples of the metallic element, the element of nonmetal and metal elements! How the properties of metals and non-metals? Try it you observe the nature of iron! How to form iron? Solid, liquid, or gas? How violent nature, hard or soft? Can iron conduct electricity or heat? Whether the metal can be hammered into thin? Whether iron can be made into a wire? How did the nature of the non-metallic elements? Sulfur, classified as non-metallic elements. Try to find examples of other non-metallic elements! Then compare the nature.

  HISTORY OF MOLECULAR

Although the existence of molecules have been accepted by many chemists since the beginning of the 19th century, there is some disagreement among physicists such as Mach, Boltzmann, Maxwell, and Gibbs, who saw molecules merely as a mathematical conception. Perrin works on Brownian motion (1911) is regarded as the final convincing evidence of the existence of the molecules scientists The earliest definitions defined molecules as the smallest particles of chemicals that still retains its composition and chemical properties This definition is often not applicable because many resource materials such as rocks, salt, and metals are composed of networks of atoms and ions that are bound chemically and not composed of discrete molecules

 3. MOLECULE

The smallest particle of a compound composed of two or more atoms, generally composed of different atoms, but some molecules are composed of the same atoms.

à The molecules are composed of the same atoms called molecules of elements (elements of diatomic and polyatomic)

à molecule consisting of different atoms called molecules of compounds

examples of compound molecules.

  Each one water molecule composed of one atom of oxygen and two hydrogen atoms

Figure 2 shows the oxygen molecules and water molecules

Atoms and complexes connected by non-covalent (ex, bound by hydrogen bonds and ionic bonds) is generally not regarded as a single molecule

4.      COMPOUND is a combination of two or more elements through a chemical reaction so that a new substance that has different properties from the elements constituent. The compound can be found easily in our daily lives, for example, only one

Compounds most frequently encountered are water (H2O), which is a combination of elements of Hydrogen and Oxygen.

The Cirri characteristics of the compound are as follows:

The characteristics of compound:

1.composed of two or more elements through chemical reactions.

2. The compounds have different properties from their constituent elements.

3. Can be decomposed into constituent elements only by ordinary chemical reaction.

4. Comparison of the mass of constituent elements always remain.

5. Can be described chemically, but not physically.

               NATURE OF COMPOUNDS

Whether water can be broken down into simpler substances that again? Yes, you can try it out by means of electrolysis of water. Water forming elements are oxygen and hydrogen. So, water is composed of oxygen gas and hydrogen gas are joined through a chemical reaction. Water with the chemical formula H2O, have different properties with its constituent elements, namely in the form of H2 and O2 gases. Water can be broken down into its constituent elements, so-called

compound. The hydrogen and oxygen are called elements. Thus, the compound is a substance formed from the elements with a certain ratio and fixed through a chemical reaction. Thus, the nature of the compound is not equal to the nature of its constituent elements. The compound can be separated into the elements or into simpler compounds through chemical reactions.

Within each compound constituent elements have a fixed mass ratio and specific. For example,

a. Water (H2O), the ratio of the mass of its constituent elements, namely

Hydrogen: Oxygen is 1: 8

b. Sugar (C12 H22 O11), the ratio of the mass of constituent elements

namely Carbon: Oxygen: Hydrogen is 72: 88: 11

c. Ethanol (C2 H5OH), the ratio of the mass of constituent elements

namely Carbon: Oxygen: Hydrogen is 12: 8: 3

5.      MIX is a combination of two or more types of substances. The mixture has different properties to the compound. In a mixture of component properties are not lost. When the salt is dissolved in water, the substance was not compounded, but mixed

The taste of salt before and after mixed remain salty, so does the water. Water before and after mixed mixed still be able to extinguish the fire. Then also the salt with water can be mixed in various compositions as desired. Not so with compounding. The compound has a specific composition. Water as an example, is composed of hydrogen and oxygen with the atomic ratio of 2: 1, we can state that fused to form new substances (lasting chemically), while mixed not form new substances

MIXED PROPERTIES

Try you pick up a handful of soil! Pay special attention to what is found in a handful of soil again? is

No sand, plastic, wood, and gravel?

Land classified in the mixture, the mixture

a wide range of elements and compounds. The original properties of substances forming

the mixture is still visible, so that the components of the mixture

can be identified and can be separated again. Comparison

constituent substances do not necessarily like the compound.

There are two kinds of mixtures,  a homogeneous mixture and mix heterogeneous.

a. Homogeneous mix

Observe carefully syrup glass of water. Whether clear or cloudy? Does sugar or syrup can be mixed? When the syrup clear water and mixed evenly, can be classified as a homogeneous mixture. This homogeneous mixture is commonly called a solution. In solution, each part of the same structure. So in the solution of the syrup are two constituent solution, namely water and sugar. Air-called solvent, while sugar is called the solute. Examples of other homogeneous mixture is soft drinks (soft drinks) and floor cleaning solution.

b. Heterogeneous mix

Observe glass of water mixed with sand. What lies at the bottom of the glass? What is floating? Does the color of the crystal clear water? Is it a mixture of sand and water evenly? If

constituent substances mixed unevenly and this mixture each part is not the same structure, it is called a heterogeneous mix (please see Figure 3.8). Another example is a heterogeneous mixture of coffee water (liquid form) and a mixture of flour with

water (solid form).