12:41 Jul 17, 2020 |
English language (monolingual) [PRO] Science - Chemistry; Chem Sci/Eng | |||||||
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| Selected response from: Kiet Bach United States Local time: 01:44 | ||||||
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Discussion entries: 5 | |
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most stable valence of carbon in co2 ... and therefore CO2 is a very stable molecule Explanation: Unfortunately, carbon in CO2 is in its most stable valence (IV) and therefore CO2 is a very stable molecule (Gf0 = -394.228 kJ/mol). The "IV" means 1 carbon atom contributes 4 electrons in the bond with 2 oxygen atoms. I think that is OK. https://www.sciencequiz.net/newjcscience/jcchemistry/bonding... The main thing is that CO2 is a very stable molecule, not carbon (which is an atom, not molecule). I think the article wants to say that unfortunately CO2 is a very stable molecule, therefore it is hard to break it up (into carbon and oxygen). |
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Carbon in CO2 is a very stable molecule because C valance has 4 electrons (1s2 2s2) Explanation: Each element has electron shell(s) orbiting their nucleus and valance is the last or outer most orbit where number of electrons in this valence shell defines potential reactivity of that particular element. In other words the valance electrons are available for chemical bond formation. As an American and as a chemist i use valance, however “valency” is used in British English. Instead of using roman numerals the valance electrons should be defined with “s” such as 1s1 for H. Regarding reactivity: the valance shell accommodates 8 electrons (valence shell electron octet, except “H”). Elements with 8 electrons are nobel gases and they are inert (nonreactive) therefore any element with less than 8 electrons can be considered reactive. However “C” (or carbon group elements) are the most stable elements because they are right in the middle of the spectrum, where they have 4 electrons. In other words elements with 1 to 3 valance electrons are considered “donors” and elements with 5 to 7 valance electrons are considered “acceptors.” Thus they make chemical bonds by combining their valance electrons to 8. As you can see because Carbon has 4 electrons it is neither a donor nor it is an acceptor. Therefore bonding with C is considered very stable. Thus I would have rephrased the author’s statement: “Carbon in CO2 is a very stable molecule because C valance has 4 electrons (1s2 2s2).” -------------------------------------------------- Note added at 16 hrs (2020-07-18 05:17:28 GMT) -------------------------------------------------- Well it should have been the following sorry: “CO2 is a very stable molecule because carbon valance has 4 electrons (1s2 2s2).” https://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/intro2.htm |
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Quaternary carbon in CO2 is in the most stable state Explanation: The valence or valency is the ability of an element to combine with other atoms. It's not a state, but a degree or measure, that is, it can increase or decrease. Therefore, Unfortunately, carbon in CO2 is in the highest valence number (IV), so carbon dioxide is a very stable molecule (Gf0 = -394.228 kJ/mol). -------------------------------------------------- Note added at 17 hrs (2020-07-18 06:31:38 GMT) -------------------------------------------------- Valence cannot be stabilised, and in the second clause, carbon dioxide is a molecule, not carbon. |
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9 hrs |
Reference Reference information: CO2 Reduction: From the Electrochemical to Photochemical Approach Jinghua Wu Yang Huang Wen Ye Yanguang Li First published: 12 September 2017 https://doi.org/10.1002/advs.201700194 Citations: 162 ... 2 Fundamentals of Electrocatalytic and Photocatalytic CO2 Reduction CO2 is one of the most stable molecules due to the strong CO double bond with bonding energy of 750 kJ mol−1—considerably larger than that of CC (336 kJ mol−1), CO (327 kJ mol−1), or CH bond (411 kJ mol−1). CO2 reduction via either the electrocatalytic or the photocatalytic approach is a thermodynamically uphill reaction and demands significant energy input to break the CO bond. To make it even more complicated, CO2 reduction may proceed via several different reaction pathways with the transfer of 2, 4, 6, 8, 12 or even more electrons and yielding diverse reduction products including carbon monoxide (CO), formic acid (HCOOH), methane (CH4), ethylene (C2H4), and many others depending on the nature of the electrocatalysts or photocatalysts as well as the actual experimental conditions.27, 28 As a result, electrocatalytic or photocatalytic CO2 reduction is generally suffered from very limited efficiency and poor selectivity. https://onlinelibrary.wiley.com/doi/10.1002/advs.201700194 -------------------------------------------------- Note added at 1 day 6 hrs (2020-07-18 19:11:10 GMT) -------------------------------------------------- regarding "IV" 2. COVALENT BONDING, OCTET RULE, POLARITY,AND BASIC TYPES OF FORMULAS LEARNING OBJECTIVESTo introduce the basic principles of covalent bonding, different types of molecular representations, bondpolarity and its role in electronic density distributions, and physical properties of molecules. VALENCE ELECTRONS They are those found in the highest energy level of the atom, or outer shell. In the periodic table, the number of valence electrons is given by the group number. For example, in the second row, the nonmetals are: BORON Group III 3 valence electrons2s2, 2p1 CARBON Group IV 4 valence electrons2s2, 2p2 NITROGEN Group V 5 valence electrons2s2, 2p3 OXYGEN Group VI 6 valence electrons2s2, 2p4 FLUORINE Group VII 7 valence electrons 2s2, 2p5 OCTET RULE .... https://personal.utdallas.edu/~scortes/ochem/OChem1_Lecture/... IOW: nothing wrong with it ... |
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