What is Co2: Definition and 307 Discussions

Carbon dioxide (chemical formula CO2) is an acidic colorless gas with a density about 53% higher than that of dry air. Carbon dioxide molecules consist of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth's atmosphere as a trace gas. The current concentration is about 0.04% (412 ppm) by volume, having risen from pre-industrial levels of 280 ppm. Natural sources include volcanoes, hot springs and geysers, and it is freed from carbonate rocks by dissolution in water and acids. Because carbon dioxide is soluble in water, it occurs naturally in groundwater, rivers and lakes, ice caps, glaciers and seawater. It is present in deposits of petroleum and natural gas. Carbon dioxide has a sharp and acidic odor and generates the taste of soda water in the mouth. However, at normally encountered concentrations it is odorless.As the source of available carbon in the carbon cycle, atmospheric carbon dioxide is the primary carbon source for life on Earth and its concentration in Earth's pre-industrial atmosphere since late in the Precambrian has been regulated by photosynthetic organisms and geological phenomena. Plants, algae and cyanobacteria use light energy to photosynthesize carbohydrate from carbon dioxide and water, with oxygen produced as a waste product. CO2 is produced by all aerobic organisms when they metabolize organic compounds to produce energy by respiration. For instance, plants use it to produce carbohydrates in a process called photosynthesis. Since humans and animals depend on plants for food, photosynthesis, and therefore CO2, is necessary for the survival of life on earth.
It is returned to water via the gills of fish and to the air via the lungs of air-breathing land animals, including humans. Carbon dioxide is produced during the processes of decay of organic materials and the fermentation of sugars in bread, beer and wine making. It is produced by combustion of wood, peat and other organic materials and fossil fuels such as coal, petroleum and natural gas. It is an unwanted byproduct in many large scale oxidation processes, for example, in the production of acrylic acid (over 5 million tons/year).It is a versatile industrial material, used, for example, as an inert gas in welding and fire extinguishers, as a pressurizing gas in air guns and oil recovery, as a chemical feedstock and as a supercritical fluid solvent in decaffeination of coffee and supercritical drying. It is added to drinking water and carbonated beverages including beer and sparkling wine to add effervescence. The frozen solid form of CO2, known as dry ice is used as a refrigerant and as an abrasive in dry-ice blasting. It is a feedstock for the synthesis of fuels and chemicals.Carbon dioxide is the most significant long-lived greenhouse gas in Earth's atmosphere. Since the Industrial Revolution anthropogenic emissions – primarily from use of fossil fuels and deforestation – have rapidly increased its concentration in the atmosphere, leading to global warming. Carbon dioxide also causes ocean acidification because it dissolves in water to form carbonic acid.

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  1. V

    Diffusion Coefficient of CO2 in Air - Raymond

    Hi! I am studying the diffusion of CO2, can anyone tell me the value (or/and any references) of the diffusion coefficient (and/or mean thermal speed and mean free path) of CO2 in normal air? Many Many and a hundred many thanks! Raymond
  2. H

    CO2 Pressure Formula: Determine Pressure at Any Temperature

    I'm trying to figure a formula to determine what the pressure is in a CO2 bottle, while the liquid is still present. I am familiar with a CO2 Dynamics chart, but would like to know what the pressure would be at any temperature. So far, what I have found through numerous hours of searching...
  3. T

    Vapor density in kg/m3 in CO2 absorber

    hello all, I got a bit of a problem. I want to calculate the vapor density (kg/ m3 or lbs/ ft3) with the following facts: temp: 40C pressure : 20-31 bar flow rate: 1000-10000 kmole/ hr MW avg: 10-12 g/ mol (it is a mixture of H2, CO, CO2, CH4, H2O)> mostly H2 I wanted to know which...
  4. M

    CO2 laser and sigarette smoke question

    In 1975 I've got the job in lab constructing middle power one mode CO2 lasers for outer space object location (they used C and O isotopes for reducing losses in atmosfere). The main joke for newbies of our lab's boss (Yuri Vasilievich Pechenin) was to breathe sigarette smoke from mouth into...
  5. P

    Root mean square velocity of CO2 molecules

    Homework Statement If the translationa speed of the water vapor molecules (H2O) in ir is 648 m/s, what is the translational rms speed of the carbon dioxide molecules in the same air? Both gases are at the same tmperature. Homework Equations V^2 = (3kT)/m The Attempt at a Solution...
  6. M

    Why does salt and ethanol affect CO2 production in fermentation?

    Why does salt and ethanol affect carbon dioxide production in the fermentation process of sucrose? Is it because the yeast has to break the sugar down by hydrolysis and that ethanol and salt are soluble, thus, in 'competition' with the yeast because they are occupying needed water molecules...
  7. U

    Thermodynamics(Second Virial Coefficient of CO2)

    Experimental Physical Chemistry ,Experiment #4 Any Help would be appreciated Is it possible for a gas to have a positive value of A2 at room temperature? If so which gas comes to mind? What are the advantages of having Ve > Vs ? Are there any advantages to having Ve < Vs Why must the...
  8. B

    Homemade liquid rocket engine all based around a CO2

    Ok, so if there is a better place for this, please do move it mods, I just couldn't find a place to post project related stuff so I chose this part of the site. Anyways, I'm working on a homemade liquid rocket engine all based around a CO2 cartridge combustion chamber. This project also has the...
  9. P

    Global warming is not caused by CO2

    http://www.newsmax.com/insidecover/global_warming/2007/12/10/55974.html What do you make of that? that's not going to go down very well at the IPCC, that's for sure! Amazing really that it has taken so long for people to realize that variation in the original source of Earths heat can effect...
  10. V

    Nuclear Power Plant: 1GW/Year CO2 Emissions

    I think this might be an easy one but I am stucked right now and would really appreciate some help. How much mas is produced under a year by a nuclear power plant that gives 1,0 GW. Edit: ok seems like i made the newbie mistake to post this in the wrong forum, please forgive me moderator...
  11. T

    Help with reaction CO+NO2 = CO2 + NO and activation energy for reverse

    For the reaction CO+NO2 = CO2 + NO, the activation energy for the forward reaction is 135 Kj/mol of CO reacted. a) Determine the heat of the reaction...
  12. D

    Distinguishing Between CO2 and Ar

    [SOLVED] Distinguishing Between CO2 and Ar Explain how you would distinguish between argon gas and carbon dioxide gas My first thought was to boil some water to remove any dissolved gases, and then pass the two gases through samples of the water. The CO2 would react to form a weak solution...
  13. D

    How Does CO2 Volume Change When Released to Ambient Air?

    I need a formula to figure out the expansion of CO2. Ex: if I'm at sea level, "room temp", I've got 1cubic foot of CO2 at 120psi, What is the volume when its released to ambient air ? Can anyone help? Shawn
  14. M

    Adiabatic expansion of CO2 - rate of cooling

    Hi Physics forum, I have a pipe which is of length L, inner diameter D. It is packed with CO2 at pressure P (assume it's still a gas with none of this funny supercritical business!) and temperature T. The density of the CO2 is rho and the joule-kelvin coefficient is mu. the pipe is initially...
  15. rocomath

    Calculating Volume of CO2 Released from a Can

    I am so lost as to how I should approach this problem A soft drink is made by dissolving CO2 @ 3.00 atm in a flavored solution and sealing the solution in an aluminum can @ 20C. What volume of CO2 is released when a 355-ml can is opened to 1.00 atm @ 20C and all the CO2 is allowed to escape...
  16. Andre

    News CO2 Emissions: China vs US: Casus Belli?

    It has all the potential, the eve of the emission war: http://english.people.com.cn/200706/22/eng20070622_386680.html And sure enough: http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/06/21/eagore21.xml There is no climate crisis, only a perception thereof. Kind of Iraqi...
  17. U

    Homework: CO2 Volume, Pressure, Temperature, and Moles

    Homework Statement A 200g sample of CO2 occupies a volume of 110 L at a pressure of 1 atm. a) What is the number of moles in the gas b) What is the temperature? c) if the volume is increased up to 200 L and the temperature is kept constant. what is the new pressure. Homework...
  18. S

    What is the pressure of CO2 at the nozzle exit of a rocket?

    Homework Statement Initial mass of the rocket is M = 30 x 10^3 kg, while its initial acceleration a = 3g. The rocket has four nozzles of diameter D = 20 cm each. Burning fuel leaves the nozzle with velocity v = 2.0 km/s having temperature T = 600◦C. Assuming fuel is burned completely and the...
  19. J

    Calculating CO2 invassion/diffusion into water

    Hi, I trying to help someone with an aquarium Experiment. Anyways I'm trying to find sources on how to calculate how fast CO2 should diffuse through their still water surface in response to CO2 demand due to their plants. I have the aquarium dimensions, plant biomass produced over the time...
  20. W

    How do I calculate CO2 output from a compressed air tank with 5% CO2?

    If I have a tank of compressed air with 5% CO2 and 95% air, and I know the flow rate coming out of the tank is 0.01 LPM, how do I determine the number of [moles/L] of CO2 coming out of the tank?
  21. W

    CO2 bubbling in phosphate buffered saline (pH 7.4)

    I bubbled 5% CO2 through a needle into 30 mL of PBS open to atmosphere (25C) for approximately one hour and reduced the pH from 7.40 to 6.48. I was wondering if I can find the concentration of CO2 in the solution over time with one known (pH) using the Henderson-Haselbalch equation? I am...
  22. A

    Reactions of N2 & O2 with CO & CO2

    im wondering what reaction would likely occur 2NO (g) → N2(g) + O2(g) or the reverse 2CO (g) + O2(g) → 2CO2 (g) or the reverse well the first one would occur if it were the reverse because of the high temperatures in the engine, but I am wondering about carbon monoxide, what do you guys think
  23. Andre

    The Controversial History of Atmospheric CO2 Measurements: A Critical Analysis"

    Ernst Beck has published a highly controversial paper about the chemical measurements of CO2 is the past two centuries with chemical measurements and the problems thereof: Beck, E-G, 2007; 180 Years of Atmospheric CO2 Gas Analysis by Chemical Methods; Energy & Environment, Vol 18 No. 2, 2007...
  24. Andre

    The positive feedback factor of CO2

    In the other thread we / errm I discussed that theories cannot be proven but they can be falsified. Actually, without positive feedback, more CO2 is merely a mild friendly climate alleviator at the most So the issue here is the positive feedback factor of CO2 on the termination of ice...
  25. C

    Bonding Order: CO < CO3^2- < CO2

    Homework Statement Arrange in increasing order of bond length: CO, CO2, CO3^2- The Attempt at a Solution CO2 has double bonds, CO has back bonds and Co3 2- has a partial double bond (resonance), so it should be CO2>Co3 2->CO. Is that right?
  26. J

    Calculate CO2 Mass from Gasoline Combustion | Octane & CO2 Problem Solved!

    I have the answer to the problem... only my problem is I can figure out how in the world world they came up with it. Here it is... I am sure it a pretty easy equation... only I don't get it! Calculate the mass of CO2 produced by the combustion of a tank of gasoline. Assume the mass of...
  27. J

    How to separate CO2 into C and O2

    How to separate CO2 into C and O2, how can this be done, will this require, much energy?
  28. BobG

    CO2 Emissions Impact: Greenhouse Effect & Space Debris Concerns

    http://www.nrl.navy.mil/Review05/images/05Space(Picone).pdf Greenhouse Effect Could Cause a Space Problem Always focusing on the negative. :rolleyes: Actually, the positive benefit (have to reboost the satellite less often) is limited to only a few satellites, while the increasing...
  29. Andrew Mason

    BIENT: CO2 Sequestration: Is Burying CO2 Safe?

    There is a big move in the fossil fuel industry, particularly coal, to solve the problem of green-house gas emissions by sequestering CO2 in the Earth in geological formations that are believed to be stable. This gives rise to a number of questions to which I would like to see comments...
  30. Mk

    Why is the CO2 concentration so erratic in the north?

    0? latitude and north, the CO2 concentration over time goes from rather soft to erratic. What is responsible for this? Also, what is the mechanism in which CO2 concentration drops and rises every year?
  31. Z

    Liters of CO2 produced by 8.4 g NaHCO3

    I'm on a ridiculous pace for completing a year's worth of Chemistry... I have two weeks left to finish over a semester's worth, so I'm struggling to learn all the concepts thoroughly and get decent grades. And so I keep getting stuck on problems. This problem is really giving me a headache...
  32. Mk

    Ocean plankton found to absorb less CO2 than expected

    http://www.newscientist.com/article.ns?id=mg19125676.000&print=true Ooopsies. We guessed and guessed wrong. Then we guess again that we weren't actually wrong, it is just that the plankton are deficient in specfic nitrates and iron. That's the vibe I got.
  33. R

    Will the temperature of CO2 under pressure change when released?

    Hi, Can someone help me find out what happens to temp of CO2 when under pressure? Its hard for me to throw any quantities at this so I am kind of guessing up a scenario.! Say you have a a steel box of 1m^3 and fill it with CO2 (which is 20'c) to a pressure of say 4 bar and then put this...
  34. S

    Chemical asorb sun energy?high CO2 in atmosphere

    good day to everyone, i wish to ask what chemical in our environment asorb some energy from sun? and what it has to do with high C02 level in the atmosphere? thanks in advance
  35. V

    Partial Pressure Problem: 3 Tanks, H2, N2, CO2 - Total Pressure 5.5 atm

    Temperature is constant. At first, this system is closed. In tank one: A 2 Liter tank containing H2 at a pressure of 1.5 atmospheres. In tank two: A 1 Liter tank containing N2 at a pressure of 3 atmospheres. In tank three: A 4 Liter tank containing CO2 at a pressure of 1...
  36. R

    Calculating CO2 Output from Alka-Seltzer and Water Lab

    Finding Amount of CO2 Help Please I am having trouble with my Alka-Seltzer, Water lab. The purpose of the lab is to figure out how much CO2 is produced when an amount of Alka-Seltzer is mixed with an amount of water. The only equation we have is: Alka-Seltzer + H2O ---> CO2 + Products...
  37. A

    Why Does Co2+ Have a Pink Color?

    why is Co2+ pink?
  38. Mk

    Ice core data shows 27% increase in CO2

    http://news.yahoo.com/s/ap/20051125/ap_on_sc/greenhouse_gas http://www.abc.net.au/science/news/stories/s1516607.htm http://www.newscientist.com/article.ns?id=dn8369&print=true
  39. J

    Structure of Solid CO2: Face-Centered Cubic w/ 4 Atoms?

    If found a few places that suggest that CO2 1 has a face center cubic with 4 CO2 atoms in the unit cell. Does this sound right? I could also use some literature source that backs this up.
  40. S

    Help With Balancing CO2+ Mg -> MgC + O2

    I don't know if I solved this problem correctly. Balance the equation: CO2+ Mg -> MgC + O2 Is this the right end result and can someone help me figure out the state of matter for each.
  41. D

    CO2 Concentrations by Hemisphere

    I recently read an article that stated that the Arctic ice cap is melting at a geologically rapid rate and that the air temperature over the North Pole is doing the same. The link is below: http://www.msnbc.msn.com/id/9527485/ I was wondering if any data have been collected regarding CO2...
  42. C

    Balancing Chemical Reactions: 0.6 O2, 0.8 CO, 0.5 CO2

    Help me understand please 0.6 mole of O2, 0.8 mole of CO and 0.5 mole of CO2 are added to a 2-L container. The system is heated and 0.15 mole of CO2 is formed. Does that mean that on top of the initial 0.5 mole of CO2 an additional 0.15 mole of CO2 is formed or does that mean that in total...
  43. Andre

    Relationship between CO2 and Global Warming

    The vote of the majority may say more about the convincing power of the ideas than provide an good understanding of the reality. But what do we think?
  44. K

    Calculating CO2 Dissolution in Water at Room Temperature

    Gday, Just wondering how to work out at what pressure 7g of CO2 will dissolve in 375ml of water at room temperature. Do I need empirical data? Or can I do it analytically? Thanks, knarl.
  45. S

    Can CO2 canisters be used to power a water rocket?

    Heya. Let's say I want to build a water rocket and I want to pressurise it with a 12 or 16 g CO2 canister used for powering airguns. I want to calculate the optimal size of the pressure tank, and I want to predict the thrust of this device at various nozzle diameters. So here's the...
  46. K

    CO2 Safety: Is It Really Risk-Free?

    I was at work today, and this guy named harold who is pretty smart was discussing the safety of CO2 with his coworker. We fill CO2 tanks like those used for grilling (I think)..anyway, he said that unlike compressed air, you cannot get hurt by CO2 rushing out of a broken valve. He said that...
  47. S

    Efficiency is 13% for CO2 fixation using solar radiation Photosynthesi

    What is the approx. efficiency of the conversion of light energy to chemical energy in photosynthesis? a. 100% b. 95% c. 15% d. 1% I doubt that it is 100%. Is it 15%? I did a search, and I read that the efficiency is 13% for CO2 fixation using solar radiation. I don't know if this is...
  48. S

    SFE CO2 Supercritical Extraction questions

    Can someone possibly give me some links or info which, in more detail will explain the mechanics and process of SFE CO2 extraction? Something beyond the ' CO2 is heated to 31 C at 74 bars' . I assume the unit is charged with the extraction media, charged with liquid CO2, brought to 74 bars...
  49. N

    How does starvation affect carbon dioxide output in crickets?

    I performed a cricket lab on three groups of crickets: fully fed, starved for 48 hrs, starved for 96 hours to see how these conditions would affect their carbon dioxide ouput.. The results attained were: 19 (Fed), 22 (48 hrs) and 17.5 (96 hrs) <--measured in μl/min of carbon dioxide the...
  50. A

    Supercritic CO2 as an extraction solvent

    Last semester we extracted caffeine from tea with CH2Cl2 and we were told it's possible to do the same thing with liquid CO2. This is interesting but pretty hard to do since you need high pressure/low temp in order to get liquid CO2. My question is: would it be possible to use liquid nitrogen...
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