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. A

    B How long does it take to reach harmful CO2 levels in a room?

    • I exhale 1 kg of CO2 per 24 hours = 41.67g/h (average) • Co2 indoors after ventilation = outdoors = 400 ppm (world average) • Co2 indoors threshold = 1000 ppm (cognitive effect) • Room volume = 32.5 m3 • Details to neglect: window and door closed tight, no HVAC system or other ventilation...
  2. Astronuc

    CO2 shortage affecting beer and meat supply in US

    A shortage of carbon dioxide (CO2) in the U.S. is leading to complications at a number of breweries and food suppliers across the country. https://time.com/6215461/carbon-dioxide-beer-shortage/ Denbury Energy issued a statement that the contamination was a "minor issue", and they maintain...
  3. Astronuc

    CO2 allows volcanoes to form persistent lava lakes at the surface

    Antarctica's only active volcano shows how CO2 allows volcanoes to form persistent lava lakes at the surface https://phys.org/news/2022-05-antarctica-volcano-co2-volcanoes-persistent.html
  4. A

    Measurement of actual CO2 mass emitted from a diesel engine

    I was wondering if there is a method to measure the actual total mass of carbon dioxide (CO2) emitted from a diesel engine used with a generator for power generation (https://www.cat.com/en_US/products/new/power-systems/electric-power/diesel-generator-sets/1000028914.html). Infrared CO2 sensors...
  5. M

    Calculating CO2 Concentration For Pepper Spray Devices

    I have a kid who wants to do a report on aerosols. As I understand, we have researched that for pepper spray devices liquid CO2 is used as a propellant, but we can't find out how they calculate the concentration. Is there a place we can find the right formulas needed?
  6. Philip Koeck

    A Molar heat capacity of CO2 is too high. Why?

    At very high temperatures CO2 should have Cp = 15/2 R, since there are 3 translational, 2 rotational and 4 vibrational degrees of freedom. Experimental values are a bit higher than that, at least according to a figure I found on the internet. Is that correct? And what is the explanation? A...
  7. theycallmevirgo

    Industrial CO2 laser temperature management

    Here it is specified that optimum operating temp for industrial C02 laser is within the range 59 °F to 77 °F. This is what is generally specified online, but it leads to a number of questions; How is this measured? Does it refer to the whole unit, or the point of emission of the beam, or some...
  8. M

    B CO2 Emissions, Gas Vs Electric

    I read that a kg of gas provides about 13kWh (47.5MJ) of energy and that burning a kg of gas emits about 3.15 kg of CO2. So presumably a gas-powered engine emits 3.15/13 or about .242kg of CO2 per kWh of work, right? According to the EIA, the US electric grid emits about 0.85lb or 0.386kg of...
  9. O

    Excess CO2 Problem Solved by making starch out of CO2?

    Scientists reported successful making of starch out of CO2. https://newatlas.com/science/artificial-synthesis-starch-from-co2/ Climate crisis averted?
  10. M

    Historic CO2 levels, climate change

    Not trolling here, just have genuine confusion over CO2 levels comparied to what we believe CO2 levels have been historically and their effect on climate change. I recently saw some Facebook group infographic posts which claimed that CO2 concentration in the atmosphere is the lowest it has ever...
  11. H

    Exploring Pressure Variations of CO2 Gas at 200°C

    A container of 0.5l containing 6 moles of CO2 are heated to 200 ° C on is interested in explaining the pressure variations between the pressure of a perfect gas and the actual value measured on a pressure gauge. The coefficients of the real gas a=3.59 [atm l2/mol2-] b=0.0427 [l /mol] indicate...
  12. I

    Chemistry CO2 and H2CO3 Concentrations in Aqueous Solution: Understanding the Relationship

    The solution says that the concentration of CO2 is equal to the concentration of H2CO3, which can be used to solve the rest of the problem. Does CO2 turn completely into H2CO3 when dissolved in aqueous solution? Thanks.
  13. M

    B How long will it take to reach 1000ppm CO2 from 2000ppm

    would this be a quadradic equation since its dealing with half life? I think in 500/50 = 10 minutes, the fan would have brought 500 CF of fresh air, but the out fan would have been taking out the same amount of air which includes the fresh air, so at 10 minutes, it should have less then half the...
  14. D

    Rotational partition function for CO2 molecule

    Hello fellow physicists, I need to calculate the rotational partition function for a CO2 molecule. I'm running into problems because I've found examples were they say this rotational partition function is: ##\zeta^r= \frac T {\sigma \theta_r} = \frac {2IkT} {\sigma \hbar^3}## Where...
  15. M

    Why is the CO2 level lower in my house than outside?

    How is this possible? I can't think of what could be absorbing Co2 inside my house, when I am producing it at a pretty high rate. I have my HVAC running on a frequent cycle mode also. I have no plants. The sensor...
  16. M

    Optimizing Air Flow for CO2 and Heat Loss in Vans

    My goal is to determine the ideal amount of air flow, in order to keep CO2 below 1000ppm and to minimize heat loss. I calculated the following based off a similar post in this forum, and I am hoping this can be verified so I know that i am in the right ballpark and going in the right direction...
  17. cwill53

    CO2 Sequestration and Cave Pressure Problem

    I've made it through the first 2 parts, it's just that part C has me stumped. I don't know how to manipulate the information I already know to figure out the total work energy required by the compressor, ##W_{compressor}##, during the process.
  18. J

    The Greenhouse Effect: Trapping IR Energy through Absorption and Re-emission

    Is the mechanism of greenhouse gases trapping energy emitted as Infra Red radiation by the cooling ground either reflecting back a 50% of the radiated IR energy back to Earth or/and the greenhouse gas molecule becoming excited with the extra energy and essentially becoming hotter? Is it just the...
  19. S

    Compression ratio and volume reduction of CO2

    The question is: If the compression ratio of car engines is increased by 10% (from 10 to 11), estimate the volume reduction in annual CO2 emission. Assume there are 30 million cars each consuming one cubic meter of fuel annually. The question is looking for a rough estimate for an answer. I...
  20. WMDhamnekar

    MHB Exploring Robert Boyle's Law: Pressure and Volume of CO2

    Robert Boyle's law states that at constant temperature, the pressure of fixed amount ( i-e number of moles n) of gas varies inversely with its volume. Mathematically, it can be written as $p ∝ \frac1V $(at constant T and n) $\Rightarrow p = k_1 \times \frac1V $ where $k_1$is a proportionality...
  21. S

    Supercritical CO2 erosion protection

    Hi. As i understand from what i have read about supercritical CO2 loops a major hurdle is erosion of the materials. especially in the hottest zones of the loop and in thin material sections and zones where the fluid changes direction or expands/compresses. But from the experiments i have read...
  22. C

    MHB Calc ∆Hf (kJ/mol) for C3H8 + 5 O2 -> 3 CO2 + 4 H2O

    Determine the total enthalpy of the reactants and the total enthalpy of the products. Record these values in Table C of the Student Worksheet. I need to know the total number of products and reactants in ∆Hf (kJ/mol) The substances are: C3H8+ 5 O2= 3 CO2 + 4 H2O please help me> please...
  23. BillTre

    CO2 reduction driven by a pH gradient

    In the world of Origin of Life hypothesizing, there now seem to be two main competing approaches. Life originating at alkaline hydrothermal vents and an origin in intermittent terrestrial pools (exposed to periods of drying) getting outflow from volcanically heated water sources. The alkaline...
  24. S

    Equilibrium concentration of co2 in beer

    Absolute pressure is gauge pressure + atmos press Guage press = 1.29 bar G 1 bar = 10^5 Pa 1.29 bar = 129,000 Pa Atmos Pres = 1.01x10^5 Pa Absolute pressure = 230,000 Pa Henrys law: P=KhC 230000Pa = (116x10^3Pa)C 1.98 mole fraction =C 70% CO2 = 1.387 mole fraction 44g Co2 in 1 mole 61.07g...
  25. S

    Calculate the equilibrium concentration of CO2 in beer in grams/liter

    Absolute pressure = Gauge press + Atmos press Atmos press = 105 Pa Co2 press = 0.1 bar g = 10000Pa Abs press = 10,105 Pa Hydrostatic pressure = absolute press + (density)(grav)(height at midpoint) = 10,105 + (1008)(9.81)(10) 10,8989.8 Pa Calc CO2 conc by henrys law P=KHC C=P/KH =...
  26. D

    Atmospheric absorbance of CO2 and impact of increaseing concentration

    This is a serious question, and it is not meant as an attempt to "debunk" greenhouse warming of the earth. Wikipedia has the below image, which shows the atmospheric transmittance as a function of wavelength. Notice the red vertical line through one of the CO2 absorption bands. We see that the...
  27. S

    Store wood in old salt mines to reduce CO2 in the atmosphere

    If trees are cut and then burned they have not reduced the CO2 in the atmosphere at all. And if they are left in the forest and then rot 90% of their mass also go back into the atmosphere. Here in Germany we have many old salt mines. I wonder if it would be a good idea to cut trees and store...
  28. AceHigh

    How Does Advanced Knowledge in Science Help Predict Future Innovations?

    BS EE and lifelong science lover. Love "predicting" things but its really just knowing science advances first. I'm curious about everything. Curiosity killed Schrodinger's cat.
  29. H

    Using moss to combat CO2 emissions

    I came across a few different articles and social media post that claim moss is far better at absorbing CO2 and other pollutants then trees. The article from the link below claims that a relatively small planter is the equivalent of 250 trees. Is this accurate? If it is, why isn't this more...
  30. H

    Detecting CO2 in the atmosphere

    I didn't notice this forum section until just now, I noticed it as I was scrolling down to the general area to ask if anyone knew of a forum that deals with climate science. What ways can we detect CO2 in the atmosphere. I've seen some social media posts that show an image of South America that...
  31. cafuffu

    Isolating CO2 in the electrolysis of Na2CO3 solution

    Hi all! This is my first question, i hope it does make sense :) I'm trying to find a way to isolate CO2 gas when doing electrolysis of a water solution with Na2CO3. I understand that i can do that with two half cells connected by a salt bridge, and i will get NaOH plus H2 gas in the cathode...
  32. T

    A How to find the volume change of CO2 when compressed into liquid?

    Hi, Can anyone guide me with an approach to find the liquid volume of CO2 when a gas of 4.14x10-6 m3 at -20°C and 1 bar is compressed to liquid at 25bar, without change in temperature?
  33. D

    Can someone please debunk this claim that CO2 does not trap heat?

    Hi everybody I follow climate denier pages and every now and then come across a claim that doesn't seem to have been debunked yet. One such claim is made here: <link to uacceptable source deleted> The gist of the article is that scientists experimented with using different gases in double...
  34. C

    Atmospheric CO2 absorption - actual quantification?

    I have read oodles of hand wavy qualitative text about 'the greenhouse effect' and it is clearly dominated by the absorption characteristics of H2O vapour. What I struggle to understand is the part of CO2 in radiative absorption, in relative quantified terms. CO2 has absorption peaks at 2.7um...
  35. E

    Heat Storage Capacity of CO2 molecules

    I am a science hobbyist and working on a paper to illustrate the impact of CO2 on Global Warming. Question – What is the Storage Capacity in joules, of one molecule of CO2 @ 20c/68f/293k. In other words, what is the maximum amount of IR energy that one molecule of CO2 can store at this...
  36. mfb

    B Coal and total CO2 emissions in the UK

    Mentor note: This thread started as side-discussion in the thread New Tokamak D Mode Success - Fusion is Almost Here, see there for earlier posts that lead to this discussion. I split the threads. Everything from post 2 to post 20 was moved, later posts were made here.
  37. L

    Optimal amount of CO2 to purge air in a device

    <Moderator's note: Moved from a homework forum.> Dear team, I wish to use CO2 to de-air a device by exploiting the physical properties of CO2 as a heavier, more dense gas to air and therefore displace air in a very thin tube that has a nozzle at the end where both air and CO2 can escape. I wish...
  38. Auto-Didact

    News Scientists turn CO2 back into coal

    Climate rewind: Scientists turn carbon dioxide back into coal The article says that this process takes place using a liquid metal catalyst at room temperature and is both efficient and scalable. The rest of the article can be read over at phys.org (link in title). The published paper (open...
  39. T

    Does sodium bicarbonate solution release CO2 when heated?

    Homework Statement Solid sodium bicarbonate decompose when it's heated above 50 celsius. However, when it is dissolved in water interactions of components changes. So what happens when sodium hydrogen carbonate solution is heated? Does it release carbon dioxide when temperature is above 50...
  40. sophiecentaur

    Absorption rate of CO2 in water

    So here's an interesting topic and I would appreciate some input from the assembled brains of PF to the question. Unfortunately I can't reveal the background to this but I want to know something about the rate that small bubbles of CO2 are likely to be dissolved in water under moderate pressure...
  41. J

    CO2 and the correlation with rising atmospheric temperatures

    I just read the policy for this forum "Earth" so i hope my next question will be approved, it is with the best intentions. My friends and i where having a discussion about CO2 and the correlation with the raising temperature, we know that CO2 is a greenhouse gas. About that, CO2 is a greenhouse...
  42. Adrian Tudini

    I Diagram of CO2 dip at 4.3 microns

    hi I am trying to find a free diagram of the CO2 absorption dip at 4.3 microns? I need it for interest purposes! Thanks.
  43. D

    CO2 [ppm] exposure relative to room volume [m^3] and air ventilation

    Hi All, I am trying to find out how much CO2 (ppm) would be released into a ventilated room (m3) from a faulty pressurized gas cylinder to calculate risk associated. Would anyone be able to help me with a formula? I was trying to work with V=nRT/P but wasn't sure how do I translate the outcome...
  44. bbbl67

    Why does photosynthesis produce O2 from CO2?

    My understanding is that the CO2 to O2 reaction is endothermic, so it takes more energy to be put in than you get back. So if plant life is attempting to get energy from photosynthesis, then why would it do an endothermic reaction which would take energy away from its cells?
  45. christang_1023

    Which one is more reactive, CO2 or NO2?

    Homework Statement Which one is more reactive, CO2 or NO2? Homework Equations The Attempt at a Solution I drew the Lewis structures of these species and found there is one delocalized electron in NO2, so I think NO2 is more reactive. Am I correct?
  46. Z

    Carbon dioxide in liquid and gaseous phases with liquid water

    What are the differences between carbon dioxide solubility (miscibility, reaction) in liquid water when in gaseous (<38 bar) and liquid (>38 bar) phase? The temperature in my experiments is usually between 0 and 5°C. The stirring speed is around 500 rpm. Is the solubility given apart from...
  47. T

    NASA NASA Challenge - CO2 Conversion

    NASA is looking for a process to use CO2 as a Carbon source on Mars; ultimate goal is to use the Carbon in the synthesis of other products. $50,000 prize. Open to U.S. citizens, permanent residents, and U.S. business entities, work must be done in the U.S...
  48. B

    Why is carbon dating not affected by atmospheric CO2 levels?

    When I read about carbon sinks and the production of CO2, I am puzzled by the trust we have in carbon dating. If I understand correctly, C14 is produced by cosmic rays and nitrogen and is considered a very steady process thus carbon dating is trusted. But if C14 is brought into biological...
  49. S

    Volume of CO2 from a Tank at 30psi

    First off, this is not a homework question nor assignment. I'm working on building a solar shower to mount on my car out of PVC, and don't feel like pumping large volumes of air with a bike pump. I'm looking at a portable air pump, or compressed gas in a tank with a regulator (and blow off...