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| Karst limestone landscape in the Burren, Co. Clare, Ireland. Limestone is a sedimentary rock composed of carbon amongst other elements. © Eugene Brennan |
1. Carbon is an Element
Unlike water which is a compound and can be broken down into hydrogen and oxygen, Carbon is an element which means it can’t be broken down into simpler substances. It has an atomic number of six which means it has six protons in its nucleus. Carbon also has an atomic mass of 12 which means it has 12 particles in its nucleus. Since a nucleus is composed of protons and neutrons, this means that there are six protons and six neutrons in the carbon nucleus. Also since the number of protons equals the number of electrons in an uncharged atom, there are six electrons in the orbitals of a carbon atom.
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| The periodic table of the elements. Carbon has an atomic number of six and is represented by the symbol “C”. Geralt, public domain image via Pixabay. |
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| A carbon atom. It has six positively charged protons and six neutrons in its central nucleus and six electrons in its outer shells. © Eugene Brennan |
2. It’s an Abundant Element in the Universe
Carbon is the 4th most comment element in space after hydrogen, helium and oxygen. On Earth it’s not so common and only the 15th most common element in the Earth’s crust.
3. Carbon Has Several Allotropes
The element doesn’t just exist in one form. It can take several forms, with radically different appearances and different mechanical properties. These different forms are called allotropes. Allotropes have different uses and we’ll find out about those later.
4. It Reacts With Other Elements and Compounds to Form Familiar Substances
Carbon reacts with other elements and compounds to form new compounds. A compound is a substance made from two or more different elements. A lot of these compounds are familiar to us. They include:
- Carbon dioxide. This has the formula CO2. A carbon dioxide molecule is made from one carbon atom and two oxygen atoms.
- Methane. Natural gas is primarily composed of methane. Its formula is CH4 so its molecule consists of one carbon atom and four hydrogen atoms.
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| Carbon dioxide (CO2) molecule Jynto (talk), Creative Commons CC0 1.0 Universal Public Domain Dedication via Wikimedia Commons |
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| Methane (CH4) molecule. Benjah-bmm27, Public domain, via Wikimedia Commons |
5. It Can be Used as a Heating Fuel
Charcoal and anthracite are two fossil fuels that have a high percentage of carbon. Charcoal is effectively boiled and charred organic material such as wood. The process to make it drives off water and volatile organic compounds to leave behind a high carbon mass. Anthracite is a type of coal low in tars. Both burn relatively cleanly and generate a lot of energy for heating homes and cooking.
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| Charcoal on a barbecue. Public domain image by llhan llhan via Pexels. |
6. Allotropes of Carbon Have Lots of Uses
Carbon has several allotropes:
- Amporphous carbon is a soft, black material. Soot is primarily composed of amorphous carbon. Its uses include toner for printers, as a pigment in inks and paints, and in the form of carbon black, added to tyres to improve wear resistance.
- Graphite is familiar to us all as the material used to make pencil lead. Graphite is a slippery material, so it’s also a useful lubricant. Another use is in nuclear reactors because of its ability to withstand high temperatures and being able to moderate (control) the flow of neutrons. Brushes in electric motors are made of graphite.
- Diamond is a white or pale yellow material. It’s the hardest known substance with several uses. Diamonds are used in jewellery making, but the hardness of diamond is what makes it really useful. A diamond tool can be used for scratching glass, enabling it to be snapped and cut. Diamond powder is used to coat cutting wheels, helping them to abrade and cut through steel and concrete more easily. Diamond bearings are used in critical machine applications because of their low friction and resistance to wear.
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| Allotropes of carbon: Diamond, graphite pencil lead and soot on hands which is essentially amorphous carbon. Top two images public domain via Pixabay, bottom image © Eugene Brennan |
7. Carbon is an Electrical Conductor
Copper and aluminium are two metals widely used in the form of cables for conducting electricity, but carbon is also a conductor. However its conductivity or ability to conduct electricity is several hundreds times less. Carbon rod electrodes are used in arc lights, and graphite brushes conduct electricity to the armature (the rotating part) inside electric motors. Again, graphite’s property of being slippy and having low friction makes it suitable for this application. Volume controls on audio and video appliances are connected internally to electronic components called potentiometers. The potentiometers use tracks made of carbon. Nowadays, tungsten filaments are used in incandescent lightbulbs — originally, carbon filaments were used.
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| Arc light search lights from WW2. Arc lights were also used for film projection in cinemas. Imperiial War Museum London. Public domain image via Wikimedia Commons |
8. Carbon is Essential for Life
Along with hydrogen, oxygen, nitrogen and sulphur, carbon is one of the essential elements for life. All life on planet earth, both animal and plant is carbon based. Silicon is in the same column in the periodic table of the elements and a topic of discussion is whether life on other planets could be carbon based. Plants also use carbon in the form of carbon dioxide. They absorb it and using a biological process called photosynthesis, turn it into oxygen, structural materials to build the plant and stored food resources. All the wood in a large tree comes from carbon dioxide extracted from the air, as does the starch and sugars stored for future use (e.g. potatoes and sugar in cane sugar).
9. Burning it Creates Greenhouse Gasses
We mentioned previously that carbon combines with oxygen to form CO2. All materials that contain carbon in their molecular makeup create CO2 when burned, not just pure carbon. These include hydrocarbon fossil fuels such as oil and gas but also non-fossil, carbon-neutral fuels like wood. Plastics and sugars produced by plants are also combustible and generate carbon dioxide when burned. CO2 is actually necessary and without it, the temperature of the surface of the Earth would be too low for plants and animals to survive. However, since it absorbs radiation coming from the Sun and also radiation reflected back from Earth towards space, too much of it isn’t good. This is known as a greenhouse effect and causes the air and sea temperatures to rise. The greenhouse effect results in faster rate of melting of polar ice caps, rises in sea levels, more intense storms, higher rainfall and migration of species northwards to avoid the heat or take advantage of the warmer environmental conditions.
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| The greenhouse effect. Efbrazil, CC BY SA 4.0 international via Wikimedia Commons |
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| Absorption of solar radiation by the Earth’s atmosphere. The black curve represents ideal black body radiation. The yellow area is solar radiation at the top of the atmosphere and red is that at sea level. Robert A. Rohde, CC SA 3.0 Unported via Wikimedia Commoms. this is a screenshot of the original SVG |
10. Carbon Based Charcoal is Used in Water Filters and Gas Masks
Charcoal is an effective filter. Its sponge-like structure is such that it acts as a material with a huge internal surface area. Imagine a sponge with lots of tiny holes. The sponge has an external surface area, but the area of the internal walls of all the tiny holes put together far surmounts this. Poisonous gases passing through a gas mask or chlorine in water can be absorbed by the solid mass of the charcoal, but they can also be adsorbed and stick to these internal surfaces, removing the contaminants.
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| Gas masks. SweetMellowChill, public domain image via Pixabay |
References
Electrical conductivity – elements and other materials. Engineering ToolBox. (n.d.).
Basics of climate change. US EPA – U.S. Environmental Protection Agency. (n.d.).
Disclaimer
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualised advice from a qualified professional.
© 2023 Eugene Brennan
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