Hidrokarbon

Hydrocarbons are the simplest alkane, a hydrocarbon that contains only single covalent bonds. Hydrocarbons are compounds whose molecular structure consists of hydrogen and carbon. The simplest molecule of the alkane is methane. Methane is a gas at standard temperature and pressure, is a major component of natural gas (Wilbraham, 1992).

Hydrocarbons can be classified according to a variety of carbon-carbon bonds they contain. Hydrocarbons with carbon-carbon single bond has called saturated hydrocarbons. Hydrocarbons with two or more carbon atoms having two or three bonds called unsaturated hydrocarbons (Fessenden, 1997).

Hydrogen and its compounds, generally divided into three major groups, namely:

1. Hydrogen consists of aliphatic carbon chain that does not cover cyclic wake. This group is often referred to as the open-chain hydrocarbons or cyclic hydrocarbons. Examples of aliphatic hydrocarbons, namely:

C2H6 (ethane) CH3CH2CH2CH2CH3 (pentane)

2. Alicyclic hydrocarbon or cyclic hydrocarbon composed of carbon atoms arranged in a ring or more.

3. Aromatic hydrocarbons are a special class of cyclic compounds that are usually described as a ring of six with a single bond and a double bond bersilih changed. The group is classified separately from acyclic and aliphatic hydrocarbons because of its unique physical and chemical properties (Shukri, 1999).

For saturated hydrocarbons, all of the carbon atoms in the alkane has four single bonds and no lone pairs. The electrons are bound strongly by both atoms. Consequently, these compounds are quite stable and is also called paraffin which means less reactive (Wilbraham, 1992).

Carbon-carbon of a hydrocarbon can come together as a chain or a ring. Saturated hydrocarbons with the atoms together in a straight chain or branched chain alkanes are classified as. A mean of each straight-chain carbon atoms of alkanes is tied to no more than two other carbon atoms. A branched-chain alkanes containing at least one carbon atom bonded to three other carbon atoms or more (Fessenden, 1997).

Straight-chain alkanes:

CH3 - CH2 - CH3


Branched-chain alkanes:


CH3 - CH - CH2 - CH3

CH3


Compounds of low molecular weight gaseous and liquid, high-molecular-weight substances are solid. Alkanes are nonpolar substance, a substance that is not soluble in water with a liquid density of less than 1.0 g / ml. In addition there is also alkanes alkenes are hydrocarbons which have one or more double bond carbon-carbon. The compound is said to be saturated because it does not have the maximum number of atoms that actually can fit any carbon (Pettruci, 1987).

Aliphatic hydrocarbons derived from petroleum, while aromatic hydrocarbons from coal. All hydrocarbons, aliphatic and aromatic have three general properties, which are not soluble in water, is lighter than water and burns in air (Wilbraham, 1992)



Merupkan alkane hydrocarbons from unsaturated aldehyde can be reacted with acetaldehyde, Zn metal in acid and added H2SO4, following the addition of H2SO4 then changes color changes to dark brown, dense metal that Zn as for being late due to the influence of H2SO4. This reaction is called reduction Clemensen, while the reaction is as follows:


O


CH3 - C - H Zn + H2SO4 C2H6


Zn metal were to act as a reductant, whereas concentrated H2SO4 serves as an oxidant. This is what causes the color change. Acetaldehyde is a group of easily reduced to aldehyde compounds with the same number of atoms number. Zinc metal is added to function as a reductant (oxidized), whereas concentrated H2SO4 solution as an oxidant (is reduced).








gas missions that have an influence on human health and global warming is often not a priority in any policy made by many countries in the world. How badly actual consequences gas emissions can we trace below.

Indeed, gas emissions from the offerings in human activity is a consequence of everyday life on planet earth. Emissions that occurred, was not solely derived from human activities, but also of the natural process. For example, the leaf respiration, volcanic eruption, the natural life in the woods, spontaneous fires in the woods, and the biochemical processes that occur in the swamp. The gas emitted naturally, according to Dr. dr. SKM Purwaka Rachmadhi School of Public Health, University of Indonesia, Jakarta, is part of the recycling process that always occurs dynamically in order to equilibrium naturally.


"For the amount of emissions that the offerings are still within the limits of the natural ability to recycle re-reschedule, gas emissions will not significantly disrupt life on Earth. However, if the gas resulting from human activity has been beyond kepasitas natural recycling, of course cause a buildup of gas, not only on the micro-environment, but also has led to faltering balance of the macro environment, which are in the form of global warming that does not directly result in public health , "said Rachmadhi.

In addition to the indirect effects of the gas, the gas content types that emissions of any potential direct effect on public health.

The presence of several components that form gas emissions from motor vehicles (carbon monoxide, nitrogen gas, and the gas nitrogen oxide gases and gas-hydrocarbons) and this is a xenobiotic substance (substances foreign to the human body), also cause a variety of health problems in humans directly. Carbon monoxide, for example, will cause interference with the transport of oxygen in the body system. Nitrogen oxide gases are gases that potentially lower the body's immunity, and hydrocarbon gases, obviously it can cause irritation, body system disorders and cancer.

Global Warming
According Rachmadhi, global warming began to be realized when at about the decade of the 1960s to the 1970s, experts are faced with data regarding the cessation of cooling air. Previously, the earth cools at a rate of half a degree every year. However, the process of global warming when it is detected in the northern hemisphere, causing the cooling of the earth stalled. Since then, conditions continued to global warming which leads to an increase in air temperature.

The experts who are members of the body of the National Oceanographic and Atmospheric Administration in the United States, and believes that global warming caused by the buildup of carbon dioxide in the upper atmosphere as a result of human activities offering. The presence of carbon dioxide in large quantities is like to be a shock for the degree of reflection or albedo of the earth to the sun which allows the earth to avoid overheating. Reflection of the earth to the sun was due to the reflection of sunlight by dust particles, clouds, water, snow, and ice.

In addition to carbon dioxide, some other gases are also known to contribute to global warming. The gases in question, among other things, gas ozone found in lower layers of the atmosphere, methane, chlorofluorocarbon gases, nitrogen oxide gases, and water vapor. Clouds are a deterrent sunlight heating the Earth, it also blocks the release of the reflected heat of the earth so that played a role in the process of global warming.

According Rachmadhi, it is known that carbon dioxide has the largest contribution in its effect on global warming, which is as much as 49 percent, while only 18 per cent methane, chlorofluorocarbon gases by 14 percent, nitrogen oxide gases 6 percent, and other gases by 13 percent. Thus, it can be said that of all kinds of gases causing global warming, carbon dioxide is the most dangerous gases. Conversely, global warming by greenhouse gases such as carbon dioxide through effect, it is a precondition for human life and most animals. If this process does not occur, the average air temperature at the earth's surface is minus 20 degrees Celsius.

However, in the recent period, the earth gets redundant supply of the gases. The burning of forests and fossil fuels, industry, power generation and motor vehicle emissions contribute to greenhouse gas carbon dioxide and other gases into the atmosphere. "The supply of these gases occur in excess and concentrated in certain places," he said.


Due to presence of Increased Number of People and Development
An increasing number of people and the accompanying development aselerasi, give rise to the availability of foodstuffs multiplied many times compared to the past. Traditional farming patterns no longer able to meet the food needs of the world's insistence, so that agricultural patterns through a revolution that forced the felling of forest for the purpose of farming land and shelter.

With the opening of farmland that causes tearing down forests absorbing carbon dioxide through the process of assimilation, increased levels of carbon dioxide in the atmosphere becomes uncontrollable. Under ordinary circumstances the forest and vegetation in general is one of the elements that contribute to transform carbon dioxide into ingredients for growth for plants in the recycling of carbon. "According to estimates, if the other conditions to support, required plant 20 billion trees every year to be able to absorb 67 percent of annual emissions of carbon dioxide gas in the United States," he said.

In addition to carbon dioxide, chlorofluorocarbon gases, which are a group of man-made gas, also have an influence on global warming. Chlorofluorocarbon gases emissions are not the result of human activity offerings. Gas group was created for several purposes, among them, as the refrigerant (or Freon dichlorodifluoromethane), solvents in industry, detergent electronic components, an additive in paint volatile materials, manufacture of rubber plastic foam (polyurethane foam rubber), and aerosol spray tube. "Although the amount of chlorofluorocarbon gases is much less than the amount of carbon dioxide, chlorofluorocarbon each molecule potential greenhouse gas effect by 10 thousand times in comparison with the molecules carbon dioxide gas," he said.

Once entered into the atmosphere, gases chlorofluorocarbons can last between 75 years up to 110 years. While there, the gas will act to eliminate ozone gas Earth's protective shield against excessive sunlight. Due to excess sun's effect on the incidence of changes in climate, animal life and flora. Phytoplankton and algae food for fish killed by excessive sun this. As a result, gas absorption kardon dioxide by the amount of water that dead flora also participated reduced.

Global warming is also a process over which poses some environmental factors effects on human life, such as the possibility of melting icebergs that will submerge some parts of the land, climate change resulting in food shortages population. Continued to take into account is the result of the migration of the population of the earth as it did in the ancient ice age with the potential for social unrest mankind globally.

Increasing the temperature of the Earth would result in a very extreme climate changes on Earth. This can lead to disruption of forests and other ecosystems, thereby reducing its ability to absorb carbon dioxide in the atmosphere. Global warming resulting in the melting of icebergs in the polar regions that could lead to rising sea levels. The greenhouse effect will also lead to rising sea temperatures that sea water expands and sea level rise occurred which resulted in the island nation will have a huge influence.

According to the simulation calculations, the greenhouse effect has increased the Earth's average temperature 1-5 ° C. If the trend of increasing greenhouse gases remain as it will lead to an increase in global warming between 1.5 to 4.5 ° C around the year 2030. With increasing concentration of CO2 in the atmosphere, the more heat waves reflected from the Earth's surface is absorbed the atmosphere. This will result in earth's surface temperature to rise.