Carbon as a Compound
Nina Yang, Period 2 Chem H, Wellnitz
A Biography of Carbon the Element
Carbon is the basis for organic chemistry, as it occurs in all living things. Interestingly enough, carbon can take the form of one of the hardest substances on earth (diamond) as well as one of the softest (graphite). It was discovered an amazing 5760 years ago, around 3750 BCE. Because it was discovered in prehistoric times in the form of charcoal, we don't know who exactly discovered it. Carbon is made in the interiors of stars (as we learned from the Chemmatters readings), and pure carbon exists freely in nature. Carbon as a compound exists in a great variety of things.
Common Uses:
-Foods (starch, sugar, fats, vitamins, proteins)
-Fuels (wood, coal, alcohol, petrol- methane, ethane, propane, butane, ethylene, ethanol)
-Household and commercial articles (paper, soap, cosmetics, oils, paints)
-Textile fabrics (cotton, wool, silk, linen, rayon, nylon)
-Drugs/disinfectants (penicillin, quinine, aspirin, sulfa drugs)
-Poisons (opium, strychnine)
-Perfumes (vanillin, camphor)
-Explosives (nitroglycerine, dynamite, picric acid, TNT)
-Dyes (indigo, congo red, malachite green)
-War gases (mustard gas, chloropicrin, lewisite)
Electron configuration: 1s2 2s2 2p2 = [He] 2s2 2p2
-Electrical Charge = 4-
Chemical reactions:
-With air: when solid carbon compounds are burned, they make carbon dioxide
-With water: doesn't react usually
-With halogens: fluorine reacts with graphite -> CF4, C2F6, C5F12
-With acids: graphite + nitric acid -> C6(CO2H)6
Physical properties:
Melting/freezing point: varied (-78°C - 3500°C)
Boiling point: 4,827°C
Sublimation point: 3800°C
Density: 2.2670 g/cm3
Color: varied (ex. diamond = clear, graphite = black)
Physical state at 25°C: varied (ex. CO2 = gas, diamond = solid)
Health hazards
Carbon as an element has very low toxicity. Chronic inhalation of carbon can result in temporary or permanent damage to lungs and heart. Other conditions include pneumoconiosis, skin conditions, carcinogenity, etc. However, some simple carbon compounds can be very harmful (such as carbon monoxide or cyanide).
Environmental effects
Carbon as an element has no detrimental effects. However, one huge environmental impact has to do with carbon compounds. The carbon footprint is one way to measure the environment effect of your lifestyle. Measured in tons of CO2, it indicates the amount of carbon dioxide and other greenhouse gases produced as a result of your daily activities.
(Below: Spectrum of Carbon in its Energy State)
Everywhere on Earth... AND in Space!
Looking to create your own compound? Well, the element carbon might be the thing you're looking for to hold your compound together! As far as we know, it is one of the most versatile elements on the Periodic Table. It can be found in countless different chemical compounds, and it is able to form a variety of structures based on its unique properties. In fact, Carbon is the basic building block of almost all of organic chemistry, and almost 20 million known molecules contain the element carbon!
Carbon can form three types of bonds: single, double, and triple. It also forms three main structures when connected to other carbon atoms: chains, branches, and rings. Even the length of these structures can differ as C-C bonds have great strength; as a result, carbon chains can be of phenomenal lengths! Not sold yet? Carbon even has four valence electrons, so it can form 4 identical covalent bonds to other atoms. Part of the reason why carbon is such a diverse element is that it can form bonds with a wide range of other elements, including Nitrogen, Sulfur, Oxygen, Chlorine, Bromine, Phosphorus, and of course, other Carbon atoms!
And which element is the most important to life on Earth? Carbon, of course!
Carbon is the second most abundant element in living organisms, and is part of all four of the major macromolecules of life: carbohydates, lipids, proteins, and nucleic acids!
Carbohydrates are the main source of energy of most cells. This chemical energy is dispensed when needed. The functional group in carbohydrates is generally a carbonyl. Carbohydrates also help with cell structure- they make up the cell walls of plant cells and the exoskeletons of some animals! Carbohydrates are generally linear, but some form rings too.
Lipids are the a good source of stored energy as well. Three main categories of lipids are fats, phospholipids, and steroids. Fatty acids generally consist of a nonpolar hydrocarbon backbone (hydrophobic) with a polar carboxyl group (hydrophilic) attached. Phospholipis are the main components of cell membranes- they consist of a polar head of glycerol, phosphate, and choline, along with two hydrophobic fatty acid tails. Finally, steroids have a carbon skeleton consisting of four fused rings.
Proteins have a great variety of functions. All proteins consist of some combination of various amino acids, of which there are 20. Each amino acid has a central carbon bonded to a hydrogen, a carboxyl group, an amino group, and a R-group. The thing that differs between amino acids is the R group. Proteins consist of amino acids joined together by peptide bonds (type of covalent bond).
Finally, there are two types of nucleic acids: DNA and RNA. DNA is responsible for storing genetic information for the synthesis of specific proteins, while RNA (three kinds: mRNA, tRNA, and rRNA) is crucial during protein synthesis. Nucleic acids consist of many nucleotides- adjacent nucleotides are joined by phosphodiester linkages (another type of covalent bond between pentose of one nucleotide and phosphate group of another), while base pairs are connected by hydrogen bonding. Each nucleotide has three parts: a nitrogenous base (A, T, G, C, or U), a pentose or five-carbon sugar (deoxyribose for DNA and ribose for RNA), and a phosphate group.
Some of its most common allotropes:
Diamond
Diamonds are colorless, transparent, and sparkly, making them perfect in items of jewelry! However, they are also extremely hard and have a high melting point, making them ideal in cutting tools! They are insoluble and water and do not conduct electricity. In diamond, all four covalent bonds leave no free electrons and no ions, giving diamond no charge as a result.
Graphite
Graphite forms in layers, and is black, shiny, and opaque. As the layers are weakly held together, graphite is very slippery, great for use in pencil leads and as lubricants. It also has a high melting point and is insoluble in water, although unlike diamond, it is a good conductor of electricity. In graphite, each carbon atom has three covalent bonds, leaving one free electron.
Fullerene
Fullerences, aka "buckyballs," consist of balls or tubes of carbon. There are many types of fullerene, including Buckminster, which is a black spherical solid that appears deep red when in solution in petrol. The tube fullerenes, called nanotubes, are great as conductors of electricity- they are often used as semiconductors in electrical circuits. They are also especially good for reinforcing structures, as their bonds are especially strong.
CARBON- GUARANTEED TO BOND RIGHT!
References
1. Website of the British Broadcasting Corporation, http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway_pre_2011/chemical/nanochemistryrev1.shtml. Accessed May 8, 2013. "Nanochemistry."
2. Website of Matthew James from the University of Bristol, http://www.chm.bris.ac.uk/webprojects2002/mjames/carbon.html. Updated June 15, 2002. Accessed May 8, 2013. "Carbon."
3. AP Biology textbook. Reece, Jane B., Urry, Lisa A., Cain, Michael L., Wasserman, Steven A., Minorsky, Peter V., & Jackson, Robert B. "5. The Structure and Function of Large Biological Molecules." Campbell Biology: Ninth Edition. Ninth Edition ed. Boston: Benjamin Cummings, 2012. 68-90. Print.