Organic compounds are carbon-based compounds. Organic compounds contain carbon bonds in which at least one carbon atom is covalently linked to an atom of another type (usually hydrogen, oxygen or nitrogen). Most polymers are organic compounds.
The name "organic" is a historical name from the 19th century.
People believed that only living things could make organic compounds and "dead" things (such as minerals) could make inorganic compounds. However, Friedrich Wöhler proved this wrong by synthesizing urea, a well-known organic compound.
There are natural organic compounds, and synthetic ones. Their structure may be described by using names, and making diagrams.
One way of showing the molecule is by drawing its structural formula. Because molecules can have complicated structures, people have made ways to show them in simple language. One way is to use line diagrams. Each atom is shown by a letter, and connected by a line to each atom with which it is has a covalent bond. One line means a single bond, two lines means a double bond and so on.
Because there is in an infinite number of possible organic compounds, language is needed to give a unique name to each one. The International Union of Pure and Applied Chemistry, or IUPAC, made a system for doing this. Although an IUPAC name makes every single possible molecule unique, the names are often long and complicated, so in everyday life, "trivial" names--unofficial but widely understood names--are used, such as the trivial names Paracetamol, Tylenol, and Acetaminophen, which are used for a compound whose IUPAC name is "N-(4-hydroxyphenyl) acetamide". Some of these trivial names are trademarks.
Natural compounds are compounds made by living beings. These could also be made in a lab, but many of these compounds are taken from nature because it is easier and less expensive to do it that way. For example, every year people grow and eat huge amounts of natural sugar and starch. Other common natural compounds are: amino acids, proteins, carbohydrates, many antibiotics like Penicillin and Amoxicillin.
Synthetic compounds are those made by people. Sometimes, this is done by taking something natural and changing the molecule in a small way, such as making glycerin from vegetable oils. Other compounds are synthesized in long, complicated reactions with many steps. Plastics are sometimes mostly natural, and other kinds are manufactured.
Since a compound is often first discovered in nature instead of being made on purpose in a lab, people may know the compound exists, and even know what it does sometimes, but not know exactly what atoms it is made of and how it is arranged. There are several ways of taking an unknown compound and finding out this structure:
Coal
Coal is a hard rock which can be burned as a solid fossil fuel. It is mostly carbon but also contains hydrogen, sulphur, oxygen and nitrogen. It is a sedimentary rock formed from peat, by the pressure of rocks laid down later on top.
Peat, and therefore coal, is formed from the remains of plants which lived millions of years ago in tropical wetlands (coal swamps), such as those of the late Carboniferous period (the Pennsylvanian). Also wood heated in an airless space can make charcoal, which is like coal.
Coal can be burned for energy or heat. About two-thirds of the coal mined today is burned in power stations to make electricity. Like oil, when coal is burned its carbon joins with oxygen in the air and makes a lot of carbon dioxide, which causes climate change. Because of that and other air pollution from coal most countries are turning to new sources of energy, such as solar power. But new coal power plants are still being built in some parts of the world, such as China.
Coal can be roasted (heated very hot in a place where there is no oxygen) to produce coke. Coke can be used in smelting to reduce metals from their ores.
Coal was the most important fuel of the Industrial Revolution. Coal was an important part of rail freight in the UK in the 20th century, forming the greater part of several companies' freight volume. Early in the 21st century most coal fired power stations in the United Kingdom and several other countries were closed to reduce greenhouse gas emissions.
Under suitable conditions, plant material is transformed step by step into
Diamond is commonly believed to be the end result of this process, but this is not true. Diamond is carbon but is not formed from coal.
Coal contains impurities. The particular impurities determine the use. Coking coal has little ash or sulfur or phosphorus. Those would spoil the iron made by the blast furnace.
Coal, when burnt, gives off almost a third more carbon dioxide per unit of energy than oil, and 80% more than natural gas. Almost half of the carbon dioxide from people is because of burning coal so it is the biggest single cause of global warming. Coal contributes to acid rain and smog, especially when burned without scrubbers. Burning coal releases toxic chemicals, including soot, mercury, and carbon monoxide, which contribute to diseases such as cancer and asthma in both humans and wild animals. Coal mining, especially mountaintop removal mining, can damage large areas of land and destroy natural habitats. Higher grades of coal burn more cleanly than lower grades, although they still pollute more than other fuels. In addition to air pollution, burning coal produces toxic coal ash, which can cause water pollution if it is accidentally released into the environment. There are several underground mine fires burning throughout the world. These underground fires release toxic smoke into the air, and can also cause the ground above to collapse. The city of Centralia, Pennsylvania was evacuated and is now abandoned due to an underground coal mine fire.
It is difficult to give exact figures for the effects of coal on health. It is claimed that because of coal every year over 800,000 people die early and millions of people get ill. Coal miners often get pneumoconiosis (black lung disease) from exposure to coal dust.
Opposition to coal pollution was one of the main reasons the modern environmental movement started in the 19th century.
Peak coal means the year in which most coal is mined or burned. Many countries have already passed their peak coal years, for example Germany in 1985 and the United States in 2008. Now those countries are mining and burning less coal. But China still mines a lot of coal and is helping a few countries, like Pakistan, mine more coal and build more coal-fired power stations. So the peak coal year for the world "may" have passed.
Compared to other non-renewable sources of energy, coal is inefficient and produces high amounts of greenhouse gases. Coal is commonly found and cheap.
The world's top coal producer is China, which produces about 4 billions tonnes each year, followed in order by India, United States, Australia, Indonesia and Russia with less than a billion tonnes each. The largest exporter by far is Australia and the largest importers are China, India and Japan.
In some cultures, Santa Claus brings coal to misbehaved children for Christmas. This legend comes from Victorian times when it was common to burn coal in the fireplace, rather than wood. Children who did not receive toys would at least get coal to stay warm.
Petroleum
Petroleum, (from Greek πέτρα - rock and έλαιο - oil) also called crude oil, is a thick and black liquid. It is a natural material mainly made of hydrocarbons. Most petroleum is found by drilling down through rocks on land or off-shore on the continental shelf. Major producers are in the Middle East, the Americas, and Russia. It is the most important world fuel source. It supplies 38% of the world's energy and is also used to make petrochemicals.