Isotope 14 of carbon, what is it, and how does it works?
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Joker gives a pretty good answer; though be it cut and paste, not that there is anything wrong with that.\nI would just like to bring to your attention that Carbon 14 dating is by no means accurate!\n"Dr. Libby, the discoverer of the C14 method, which won for him a Nobel prize, expressed his shock that human artifacts extended back only 5000 years, a finding totally in conflict with any evolutionary concept. Older dates were found to be very unreliable (CRSQ , 1972, 9:3, p.157). By this time tens of thousands of C14 dates have been published from tests performed by various laboratories around the world. In the annual volumes in which the dates are published, concerns have been expressed about many relatively young dates that violate established geological age notions. One example given was Ice-Age materials that were dated by C14 to fall within the Christian era (CRSQ , 1969, 6:2, p.114). In his book on prehistoric America, Ceram notes a classic case of the difficulties that befall C14 dating. Bones 30,000 years old were found lying above wood dated at 16,000 years (Ceram, 1971, p.257-259). "\nTake a look at this dinosaur bone (Illium bone of an Acrocanthosarus) dated at 19,000 years old.\nhttp://www.bible.ca/tracks/dating-acrocanthosarus-illium-bone.jpg\nTake a look at the source web site.  On that page if you scroll down a bit it will give you a list of carbon 14 as well at other dating methods possibly worth mentioning in your assignment. Have fun!
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Shanna and Geo06 have got this just about right.  The only thing I can add is that radiocarbon dating can not be used for more than about 70,000 years ago, and is more accurate for living things that died within the last 8,000 years.\n\nMost geologists measure rock ages in millions, or even billions, of years, so the age of the earth and the age of almost all igneous rocks is well beyond the range of carbon dating.  On top of that, igneous rocks contain very little if any carbon,  so carbon dating is not applicable here.  \n\nSo the only thing carbon 14 can be used for is to determine the time that an exchange of carbon with the atmosphere stopped, ie, the death of a living thing - the third item on your list of choices for your homework.\n\nThe half life of C-14, the radioactive isotope of carbon, is about 5730 years.  Therefore, if you know the ratio between C-14 and C-12 in the atmosphere when the organism died, and you know the ratio now, the difference in the ratio can be calculated backwards, using the half life, to estimate when the organism died. \n\nAtmospheric C-14 has not been in a constant ratio with C-12, as previously thought, so there are some serious problems with the accuracy of C-14 dating.  The problem is that the natural ratio of the carbon isotopes in the atmosphere (carbon dioxide) varies because cosmic ray bombardment of the outer atmosphere produces C-14 but not C-12.  The ratio can be predicted accurately using the ratios in old trees, where the tree rings can be used to accurately determine the age of each ring with its annual ratio, with a maximum of about 8,000 years -that's how old the oldest trees are which can establish a reference ratio.\n\nDating of artifacts is a best guess, the best method is to measure the amount of lichens growing on them, or the age of carbon in ashes found in the same spot.
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Percent abundance is relative abundance written in percent form.  i.e., If the relative abundance of isotope A is 0.45, then its percent abundance is 45%.\n\nAbundance is the fraction of atoms of a particular isotope in a naturally-occuring sample of an element.\n\ne.g., If you had 100 atoms of carbon, you'd find that it is made up of 2 isotopes: carbon-12 and carbon-13.  The relative abundance of each is 0.99 and 0.01, respectively (or 99% carbon-12 and 1% carbon-13).\n\nThe average atomic mass or weighted average atomic mass or atomic weight (see the slight mutation in terms... in this case, "weight" doesn't refer to force due to gravity, but "weighted average") is the sum of the products of mass number and relative abundance, respectively (whew!).\n\nOr, \n\natomic weight = \n(mass number of isotope A)*(relative abundance of isotope A) \n+ (mass number of isotope B)*(relative abundance of isotope B)\n+ (mass number of isotope C)*(relative abundance of isotope C)\n+ ...\n\nfor an atom with isotopes A, B, C, ...\n\nFor carbon, we can check my earlier numbers (which stomp all over significant figures and play fast and easy with mass numbers in amu's...)\n\nAtomic Weight = (12)*(0.99) + (13)*(0.01)\n= 12.01\n\nChecking the periodic table, we see that carbon's atomic weight is 12.01 amu.\n\nIf you haven't lost all interest altogether, there's an analogy to how you calculate your grade point average.  Each letter grade is a different isotope (A = 4, B = 3, etc.).  You calculate your GPA by determining the abundance of each grade and multiplying it by its weight.  Straight A's is a simple case (it always helps to be optimistic -- straight F's is an equally simple, if not depressing case): 100% A's or 1.0 relative abundance multiplied by 4 or GPA = 4.0.  But wait, you might cry... that's not how you, err, your buddy, calculates GPA.  He counts up his A's, multiplies by 4 and then divides by the number of grades (courses).  Mathwise, we can do the first and last steps out of order (since this is multiplication and division, and therefore order doesn't matter), and ... we get abundance (part/whole) again.\n\nLast digression --- in college, not all classes are equal, therefore not all grades are equal.  It's again a weighted average situation.  Let's say you get an A in Band (1 credit) and a C in Chemistry (4 credits) for a total of 5 credits.  Your GPA is then (1*4 + 4*2)/5 = 2.4.  Your buddy can barely carry a tune in a bucket, but is a chem whiz, so he gets a C in Band and an A in chemistry.  HIS GPA is (1*2 + 4*4)/5 = 3.6.  A surface reading of the situation would say "hey, this isn't fair... you both got 1 A and 1 C."  But, since colleges in their wisdom have decreed that Chemistry is 4 times harder than Band, note that 1/5 or 20% of your credits come from Band while 80% (4/5) come from Chemistry.\n\nHope that helps more than your standard wikipedia answer...
168747
In radioactivity, it is the time taken for half of the nuclei in a given sample to decay (either by alpha or beta decay).  These vary form radioisotope to another.  For example Carbon-14 has a half life of 5700 years.  This means that if I have 1 gram of carbon-14, 5,700 years from now I will end up with 0.5grams (the rest would have become Nitrogen with beta decay).  If another 5,700 years pass I end up with 0.25g (!) and not 0g as common sense would indicate.  Each time a half life passes HALF the nuclei decay!In fact 'activity' decreases as time passes.\nAs said this time interval varies a lot.  The half life of Uranium-238 is 4,470,000,000 years, while that of thorium-230 is only 75,380 years.  Other half lives are quite short.  E.g. Iodine-131 has a half life of just 8 days and Sodium-24 has a half life of just 15 hours!
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Since a humans are rather new to Earth (being as our ancestors have only been around for a million years +, we can use carbon dating. After death, carbon stops accumulating in our bodies. Carbon 14 decays at a rate of half every 5730 years. So if there is only 25% of Carbon left from the suspected original amount then 11460 years have gone by. If it is significantly old, other elements are used liuke Uranium etc...
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first of all carbon is not an organic compound it is an element. and different compounds made from carbon are included in class of organic compounds.\n\ncarbon has got atomic number 6. so its electronic configuration will be 1s2,2s2,2p2. so it contains 4 electrons in its outermost orbit, we know that there should be 8 electrons to complete the octet and make the element stable, so carbon can either gain 4 electrons or lose 4 electrons to become stable, but both requires very high amount of energy.\n\nso it goes for sharing of electrons. it has the special property of catenation, ie carbon-carbon long chain formation. no other element has such property, so carbon itself has forms such high number of compounds which not even formed by rest all elements together. so it has been given special branch of chemistry called organic chemistry while rest all elements are included in inorganic chemistry. so its versatile
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Sorry this is so long, but I have to first fix some misinformation given in other people's answers.  Specifically, carbon-14 (a.k.a. C14, carbon dating, or radiocarbon dating) is useful for dating a lot of things, but *not* fossils!  Instead, other forms of radiometric dating are used for fossils.  \n\nThe 'half-life' is a measure of how fast the process of radioactive decay causes one type of atom to decay into another type.  For example carbon-14 (C14) decays into nitrogen-14 (N14) with a half-life of 5,730 years.  This means that if you have a bone with 1 gram of C14, then after 5,730 years, 0.5 grams will have decayed to N14, leaving 0.5 grams of C14.  After another 5,730 years only 0.25 grams would remain.  And so on.\n\nNow, 5,730 years is not very long in geologic terms.  This means that after 50,000 years or so, the amount of C14 left is so small that it is practically unmeasurable.  It's for this reason that C14 dating is not much good for fossil dating, as most fossils are *much* older than 50,000 years.\n\n[Aside:  There's another reason carbon-14 dating is not useful for fossils.  It's only useful for dating once-living matter (bones, wood, teeth, shells, cloth, paper, etc.) that was incorporating carbon into its body while it lived ... either a plant that was once breathing CO2, or an animal that was eating things that contained carbon (like plants or other animals).  A fossil is not once-living matter.  It is rock that has filled in the impression left by a dead organism.  So fossils themselves may contain very little carbon of any type.]\n\nBut there are other atoms with a *much* longer half-life.  For example potassium-40 (K40) decays into argon-40 (Ar40) with a half-life of 1.26 *billion* years.  So when a rock is created by a volcano, it contains only K40 (as argon is a gas, so any Ar40 present at the time the rock forms escapes from the molten rock before it cools).  But over millions of years this K40 decays to Ar40, which remains trapped in the rock.  So a geologist can dig up a rock from a layer of strata, melt it down, and measure the amount of molten K40 and gaseous Ar40 that is released.  By the ratio of K40 to Ar40 in the rock, the geologist can calculate the age of the rock, in millions of years.  The geologist then also knows the age of anything else that was encased in the same layer of strata as the rock ... such as a fossil.\n\nCarbon-14 dating and potassium-argon dating are two forms of what are called 'radiometric dating'.  Other examples are uranium-lead dating (half-life of 700 million years), and rubidium-strontium dating (half-life of 50 billion years ... which is *very* long, considering that the earth is only 4.5 billion years old).
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Radiocarbon dating relies on a simple natural phenomenon. As the Earth's upper atmosphere is bombarded by cosmic radiation, atmospheric nitrogen is broken down into an unstable isotope of carbon - carbon 14 (C-14).
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1. Because carbon-14 has a half-life of only 5,730 years.  So after 60,000 years there is not enough left to measure reliably.  That's why carbon dating is *not* used for fossils (despite what many people, including most creationists, think) ... there are dozens of other techniques used for dating fossils and rocks.\n\n2. Because it only works on things that were eating or breathing carbon ... i.e. things that were once alive.  (So it is useless for rocks, or asteroids, much less stars.)\n\n3. Because you actually need a sample of what you are dating ... so you could not use it to date things like distant stars or galaxies (the things that go back to the Big Bang).
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Sorry but to divulge Genters location would be futile.  Attempts made at this, will result in your molecules being vaporized and then transformed into 46c4 carbon based atoms, which will then be erased
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A periodic table will generally not tell you how many neutrons are present in the nuclei of an element.  Recognize that many elements have multiple isotopes, and the atomic mass of an element reflects the weighted average (weighted by the relative abundances of the different isotopes) of the atomic masses of the individual isotopes.  Knowing the atomic number (= the number of protons) and isotopic mass of a given isotope lets you determine the number of neutrons present in that isotope (isotopic mass - atomic number = neutron number, if you round everything to whole numbers).\n\nOf course, for neutral atoms, the number of electrons is always equal to the number of protons.\n\nWhat the poster is really looking for is a chart of the nuclides, in which the atomic number is plotted on one axis, and the neutron number is plotted on the other axis.  The stable isotopes of the elements fall along a curved line (called the "valley of stability") in this diagram.  Radioactive isotopes that decay via beta-minus decay plot on the neutron-rich side of the valley of stability.  Radioactive isotopes that decay via positron (beta-plus) emission or electron capture lie on the neutron-poor side of the valley of stability.\n\nOnline charts of the nuclides can be found at:\n\n<http://wwwndc.tokai.jaeri.go.jp/CN04/index.html>\nand\n<http://atom.kaeri.re.kr/>
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Tritium.\n\nThat is the isotope of hydrogen with one proton and two neutron in the nucleus.  It is used as a low grade radio-active activator in phosphorescent paint, replacing radium which is much more dangerous.\n\n(Science Teacher below is wrong: deuterium is a stable nucleon, it is thus not radio active)
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Radiation can be used to measure minute concentrations of a substance (solute) in solution with a device called a scintillation counter.\n\nFirst, you would incorporate a radioactive isotope into the salt.  For example, combining copper(II) nitrate with sodium carbonate labeled with carbon-14, would produce a precipitate of solid copper(II) carbonate labeled with carbon-14 (of a known concentration).  \n\nYou would then isolate the labeled Cu(CO3) and allow it to reach equilibrium with distilled water.  That solution is filtered to remove the remaining solid Cu(CO3).  The water can then be analyzed using scintillation counting to determine how much radioactivity is present.\n\nThe amount of detected radioactivity is proportional to concentration of the dissolved salt.  Using the (presumably known) quantity of carbon-14 in the Cu(CO3), you can calculate the actual concentration of the dissolved salt.
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CH3CH2C(CH3)3.\nI guess you forgot to type the C before the parenthesis. If you didn't forget, then none of the answers is correct (you would be missing a carbon atom).\n\nChem-man I would have contacted you in private about this but you do not give us the option to e-mail you. I have seen several of your answers prompting askers to verify your answer through echemistryhelp. I checked the website and it is not a free one; you post a question and pay for the answer. I'd say that this is a form of indirect advertisement  which is against the community guidelines. Please refrain from doing that or I will have to report you.
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Philippe Verbiest, the lawyer for cycling's world governing body, confirmed Tuesday that a carbon isotope ratio test, which detects a subtle chemical difference between the natural and synthetic versions of testosterone, was done. The New York Times has reported the test detected the man-made hormone, but Verbiest refused to give any details of the result. \n\nThe test focuses on carbon atoms in testosterone molecules. These atoms come in different types, called isotopes. The ratio of one particular isotope to another isotope is different in synthetic versus natural testosterone. The test detects that difference. \n\nWhen the lab procedure is performed correctly it is very accurate, said Dr. Don Catlin, the director of the UCLA Olympic doping lab. He helped develop the test. Dr. Gary Wadler, an internist and author with expertise in the area of drug use by athletes, said he's not aware of anything other than synthetic testosterone that will produce a positive test result. \n\nWhen athletes take synthetic testosterone to boost performance, it typically helps them get stronger, recover faster from workouts, prevent tissue breakdown and increase their assertiveness, said Wadler, a member of the World Anti-Doping Agency who stressed he was not speaking for that group. \nVR
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Here is the basic information including some alchemy (second two references).  Carbon is so old in human time that its history will never really be known.
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def C6H14. i'm positive. hope this helps!!!