Buckingham π theorem: Difference between revisions
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The | :''Not to be confused with [[carbolic acid]], an antiquated name for [[phenol]].'' | ||
:''Carbonic acid is also an archaic name for [[carbon dioxide]].'' | |||
{{chembox | |||
| Watchedfields = changed | |||
| verifiedrevid = 477313558 | |||
| ImageFileL1_Ref = {{chemboximage|correct|??}} | |||
| ImageFileL1 = Carbonic-acid-2D.svg | |||
| ImageSizeL1 = 100px | |||
| ImageNameL1 = Structural formula | |||
| ImageFileR1 = Carbonic-acid-3D-balls.png | |||
| ImageSizeR1 = 120px | |||
| ImageNameR1 = Ball-and-stick model | |||
| IUPACName = Carbonic acid | |||
| OtherNames = Carbon dioxide solution; Dihydrogen carbonate; acid of air; Aerial acid; Hydroxymethanoic acid | |||
| Section1 = {{Chembox Identifiers | |||
| KEGG_Ref = {{keggcite|correct|kegg}} | |||
| KEGG = C01353 | |||
| InChI = 1/CH2O3/c2-1(3)4/h(H2,2,3,4) | |||
| InChIKey = BVKZGUZCCUSVTD-UHFFFAOYAU | |||
| ChEMBL_Ref = {{ebicite|correct|EBI}} | |||
| ChEMBL = 1161632 | |||
| StdInChI_Ref = {{stdinchicite|correct|chemspider}} | |||
| StdInChI = 1S/CH2O3/c2-1(3)4/h(H2,2,3,4) | |||
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | |||
| StdInChIKey = BVKZGUZCCUSVTD-UHFFFAOYSA-N | |||
| CASNo = 463-79-6 | |||
| CASNo_Ref = {{cascite|correct|CAS}} | |||
| PubChem = | |||
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | |||
| ChemSpiderID = 747 | |||
| ChEBI_Ref = {{ebicite|correct|EBI}} | |||
| ChEBI = 28976 | |||
| SMILES = O=C(O)O | |||
}} | |||
| Section2 = {{Chembox Properties | |||
| Formula = H<sub>2</sub>CO<sub>3</sub> | |||
| MolarMass = 62.03 g/mol | |||
| Appearance = | |||
| Density = 1.668 g/cm<sup>3</sup> | |||
| Solubility = Exists only in solution | |||
| pKa = 6.367 (p''K''<sub>a1</sub>), 10.32 (p''K''<sub>a2</sub>) | |||
| MeltingPt = | |||
| BoilingPt = | |||
}} | |||
}} | |||
'''Carbonic acid''' is the [[chemical compound]] with the [[Molecular formula|formula]] H<sub>2</sub>CO<sub>3</sub> (equivalently OC(OH)<sub>2</sub>). It is also a name sometimes given to [[solution]]s of [[carbon dioxide]] in [[water (molecule)|water]] ([[carbonated water]]), because such solutions contain small amounts of H<sub>2</sub>CO<sub>3</sub>. Carbonic acid, which is a [[weak acid]], forms two kinds of [[Salt (chemistry)|salts]], the [[carbonate]]s and the [[bicarbonate]]s. In geology, Carbonic acid causes limestone to dissolve producing calcium bicarbonate which leads to many limestone features such as [[stalactites]] and [[stalagmites]] . | |||
==Chemical equilibrium== | |||
When carbon dioxide dissolves in water it exists in [[chemical equilibrium]] producing carbonic acid:<ref name=Green/> | |||
:CO<sub>2</sub> + H<sub>2</sub>O {{eqm}} H<sub>2</sub>CO<sub>3</sub> | |||
The [[Hydrate|hydration]] [[equilibrium constant]] at 25°C is called K<sub>h</sub>, which in the case of carbonic acid is [H<sub>2</sub>CO<sub>3</sub>]/[CO<sub>2</sub>] ≈ 1.7×10<sup>−3</sup> in pure water<ref name="HS">Housecroft and Sharpe, ''Inorganic Chemistry'', 2nd ed, Prentice-Pearson-Hall 2005, p.368.</ref> and ≈ 1.2×10<sup>−3</sup> in [[seawater]].<ref name=SB>{{Cite journal |last=Soli|first=A.L.|coauthors=R.H. Byrne |year=2002 |title=CO2 system hydration and dehydration kinetics and the equilibrium CO2/H2CO3 ratio in aqueous NaCl solution |url= |archiveurl= |archivedate= | journal=Marine chemistry |volume=78 |issue= 2–3|pages=65–73 |doi= 10.1016/S0304-4203(02)00010-5|pmid= |bibcode=}}</ref> Hence, the majority of the carbon dioxide is not converted into carbonic acid, remaining as CO<sub>2</sub> molecules. In the absence of a [[catalyst]], the equilibrium is reached quite slowly. The [[rate constant]]s are 0.039 s<sup>−1</sup> for the forward reaction (CO<sub>2</sub> + H<sub>2</sub>O → H<sub>2</sub>CO<sub>3</sub>) and 23 s<sup>−1</sup> for the reverse reaction (H<sub>2</sub>CO<sub>3</sub> → CO<sub>2</sub> + H<sub>2</sub>O). Carbonic acid is used in the making of [[soft drinks]], inexpensive and artificially carbonated sparkling wines, and other bubbly drinks. The addition of two equivalents of water to CO<sub>2</sub> would give ''[[orthocarbonic acid]]'', C(OH)<sub>4</sub>, which exists only in minute amounts in aqueous solution. | |||
Addition of base to an excess of carbonic acid gives [[bicarbonate]]. With excess base, carbonic acid reacts to give [[carbonate]] salts. | |||
== Role of carbonic acid in blood == | |||
Carbonic acid is an intermediate step in the transport of CO<sub>2</sub> out of the body via [[Gas exchange|respiratory gas exchange]]. The hydration reaction of CO<sub>2</sub> is generally very slow in the absence of a catalyst, but [[red blood cells]] contain [[carbonic anhydrase]], which both increases the reaction rate and dissociates a hydrogen ion (H<sup>+</sup>) from the resulting carbonic acid, leaving [[bicarbonate]] (HCO<sub>3</sub><sup>−</sup>) dissolved in the [[blood plasma]]. This catalysed reaction is reversed in the lungs, where it converts the bicarbonate back into CO<sub>2</sub> and allows it to be expelled. This equilibration plays an important role as a [[Buffer solution|buffer]] in mammalian blood.<ref>"excretion." Encyclopædia Britannica. Encyclopædia Britannica Ultimate Reference Suite. Chicago: Encyclopædia Britannica, 2010.</ref> | |||
== {{anchor|Ocean}} Role of carbonic acid in ocean chemistry== | |||
The oceans of the world have absorbed almost half of the CO<sub>2</sub> emitted by humans from the burning of fossil fuels.<ref name=sabine>{{cite journal|last=Sabine|first=C.L.|coauthors=et al.|year=2004|title=The Oceanic Sink for Anthropogenic CO<sub>2</sub>|url=http://www.sciencemag.org/cgi/content/short/305/5682/367"|journal=Science|volume=305|issue=5682|pages=367–371|doi=10.1126/science.1097403|pmid=15256665|format=}} {{dead link|date=May 2010}}</ref> The extra dissolved carbon dioxide has caused the ocean's average surface pH to shift by about 0.1 unit from pre-industrial levels.<ref name=unesco>{{cite web| title=Ocean Acidification Network|url=http://ioc3.unesco.org/oanet/FAQacidity.html}}</ref> This process is known as [[ocean acidification]].<ref>National Research Council. "Summary." Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean. Washington, DC: The National Academies Press, 2010. 1. Print.</ref> | |||
==Acidity of carbonic acid== | |||
Carbonic acid is one of the [[Acid#Polyprotic acids|polyprotic acid]]s: It is [[diprotic acid|diprotic]] - it has two protons, which may dissociate from the parent molecule. Thus, there are two [[Acid dissociation constant|dissociation constants]], the first one for the dissociation into the [[bicarbonate]] (also called hydrogen carbonate) ion HCO<sub>3</sub><sup>−</sup>: | |||
:H<sub>2</sub>CO<sub>3</sub> {{eqm}} HCO<sub>3</sub><sup>−</sup> + H<sup>+</sup> | |||
:''K''<sub>a1</sub> = 2.5×10<sup>−4</sup> mol/litre; p''K''<sub>a1</sub> = 3.6 at 25 °C.<ref name=Green>{{Greenwood&Earnshaw2nd}}</ref> | |||
Care must be taken when quoting and using the first dissociation constant of carbonic acid. In aqueous solution, carbonic acid exists in equilibrium with carbon dioxide, and the concentration of H<sub>2</sub>CO<sub>3</sub> is much lower than the concentration of CO<sub>2</sub>. In many analyses, H<sub>2</sub>CO<sub>3</sub> includes dissolved CO<sub>2</sub> (referred to as CO<sub>2</sub>(aq)), H<sub>2</sub>CO<sub>3</sub>* is used to represent the two species when writing the aqueous chemical equilibrium equation. The equation may be rewritten as follows:<ref name=Green/> | |||
:H<sub>2</sub>CO<sub>3</sub>* {{eqm}} HCO<sub>3</sub><sup>−</sup> + H<sup>+</sup> | |||
:''K''<sub>a</sub>(app) = 4.6×10<sup>−7</sup> mol/litre ; p''K''(app) = 6.3 at 25 °C and Ionic Strength = 0.0 | |||
Whereas this apparent p''K''<sub>a</sub> is quoted as the dissociation constant of carbonic acid, it is ambiguous: it might better be referred to as the acidity constant of dissolved carbon dioxide, as it is particularly useful for calculating the [[pH]] of CO<sub>2</sub>-containing solutions. A similar situation applies to [[sulfurous acid]] (H<sub>2</sub>SO<sub>3</sub>), which exists in equilibrium with substantial amounts of unhydrated [[sulfur dioxide]]. | |||
The second constant is for the dissociation of the [[bicarbonate]] ion into the [[carbonate]] ion CO<sub>3</sub><sup>2−</sup>: | |||
:HCO<sub>3</sub><sup>−</sup> {{eqm}} CO<sub>3</sub><sup>2−</sup> + H<sup>+</sup> | |||
:''K''<sub>a2</sub> = 4.69×10<sup>−11</sup> mol/litre ; p''K''<sub>a2</sub> = 10.329 at 25 °C and Ionic Strength = 0.0 | |||
===pH and composition of carbonic acid solutions=== | |||
At a given temperature, the composition of a pure carbonic acid solution (or of a pure CO<sub>2</sub> solution) is completely determined by the [[partial pressure]] <math>\scriptstyle p_{CO_2}</math> of carbon dioxide above the solution. To calculate this composition, account must be taken of the above equilibria between the three different carbonate forms (H<sub>2</sub>CO<sub>3</sub>, HCO<sub>3</sub><sup>−</sup> and CO<sub>3</sub><sup>2−</sup>) as well as of the hydration equilibrium between dissolved CO<sub>2</sub> and H<sub>2</sub>CO<sub>3</sub> with constant <math>\scriptstyle K_h=\frac{[H_2CO_3]}{[CO_2]}</math> (see above) and of the following equilibrium between the dissolved CO<sub>2</sub> and the gaseous CO<sub>2</sub> above the solution: | |||
:CO<sub>2</sub>(gas) {{eqm}} CO<sub>2</sub>(dissolved) with <math>\scriptstyle \frac{[CO_2]}{p_{CO_2}}=\frac{1}{k_\mathrm{H}}</math> where k<sub>H</sub>=29.76 atm/(mol/L) at 25 °C ([[Henry's law|Henry constant]]) | |||
The corresponding equilibrium equations together with the <math>\scriptstyle[H^+][OH^-]=10^{-14}</math> relation and the charge neutrality condition <math>\scriptstyle[H^+]=[OH^-]+[HCO_3^-]+2[CO_3^{2-}]</math> result in six equations for the six unknowns [CO<sub>2</sub>], [H<sub>2</sub>CO<sub>3</sub>], [H<sup>+</sup>], [OH<sup>−</sup>], [HCO<sub>3</sub><sup>−</sup>] and [CO<sub>3</sub><sup>2−</sup>], showing that the composition of the solution is fully determined by <math>\scriptstyle p_{CO_2}</math>. The equation obtained for [H<sup>+</sup>] is a cubic whose numerical solution yields the following values for the pH and the different species concentrations: | |||
{|align="center" border="1" cellspacing="0" cellpadding="2" class="wikitable" style="background:#FFF;color:#000;text-align:center" | |||
|- | |||
!style="width:9em" scope="col"| <math>\scriptstyle p_{CO_2}</math><br /><small>(atm)</small> | |||
!style="width: 5em" scope="col"| pH | |||
!style="width:9em" scope="col"| [CO<sub>2</sub>]<br /><small>(mol/L)</small> | |||
!style="width:9em" scope="col"| [H<sub>2</sub>CO<sub>3</sub>]<br /><small>(mol/L)</small> | |||
!style="width:9em" scope="col"| [HCO<sub>3</sub><sup>−</sup>]<br /><small>(mol/L)</small> | |||
!style="width:9em" scope="col"| [CO<sub>3</sub><sup>2−</sup>]<br /><small>(mol/L)</small> | |||
|- | |||
|scope="row"| {{0|1.0 ×}} 10<sup>−8</sup> | |||
| 7.00 | |||
|style="color:#666"| 3.36 × 10<sup>−10</sup> | |||
|style="color:#BBB"| 5.71 × 10<sup>−13</sup> | |||
|style="color:#000"| 1.42 × 10<sup>−{{0}}9</sup> | |||
|style="color:#666"| 7.90 × 10<sup>−13</sup> | |||
|- | |||
|scope="row"| {{0|1.0 ×}} 10<sup>−7</sup> | |||
| 6.94 | |||
|style="color:#666"| 3.36 × 10<sup>−{{0}}9</sup> | |||
|style="color:#666"| 5.71 × 10<sup>−12</sup> | |||
|style="color:#000"| 5.90 × 10<sup>−{{0}}9</sup> | |||
|style="color:#BBB"| 1.90 × 10<sup>−12</sup> | |||
|- | |||
|scope="row"| {{0|1.0 ×}} 10<sup>−6</sup> | |||
| 6.81 | |||
|style="color:#666"| 3.36 × 10<sup>−{{0}}8</sup> | |||
|style="color:#666"| 5.71 × 10<sup>−11</sup> | |||
|style="color:#000"| 9.16 × 10<sup>−{{0}}8</sup> | |||
|style="color:#BBB"| 3.30 × 10<sup>−11</sup> | |||
|- | |||
|scope="row"| {{0|1.0 ×}} 10<sup>−5</sup> | |||
| 6.42 | |||
|style="color:#666"| 3.36 × 10<sup>−{{0}}7</sup> | |||
|style="color:#666"| 5.71 × 10<sup>−10</sup> | |||
|style="color:#000"| 3.78 × 10<sup>−{{0}}7</sup> | |||
|style="color:#BBB"| 4.53 × 10<sup>−11</sup> | |||
|- | |||
|scope="row"| {{0|1.0 ×}} 10<sup>−4</sup> | |||
| 5.92 | |||
|style="color:#000"| 3.36 × 10<sup>−{{0}}6</sup> | |||
|style="color:#666"| 5.71 × 10<sup>−{{0}}9</sup> | |||
|style="color:#666"| 1.19 × 10<sup>−{{0}}6</sup> | |||
|style="color:#BBB"| 5.57 × 10<sup>−11</sup> | |||
|-style="background-color:#AFF" | |||
|scope="row"| {{0|}}3.5 × 10<sup>−4</sup> | |||
| 5.65 | |||
|style="color:#000"| 1.18 × 10<sup>−{{0}}5</sup> | |||
|style="color:#666"| 2.00 × 10<sup>−{{0}}8</sup> | |||
|style="color:#666"| 2.23 × 10<sup>−{{0}}6</sup> | |||
|style="color:#BBB"| 5.60 × 10<sup>−11</sup> | |||
|- | |||
|scope="row"| {{0|1.0 ×}} 10<sup>−3</sup> | |||
| 5.42 | |||
|style="color:#000"| 3.36 × 10<sup>−{{0}}5</sup> | |||
|style="color:#666"| 5.71 × 10<sup>−{{0}}8</sup> | |||
|style="color:#666"| 3.78 × 10<sup>−{{0}}6</sup> | |||
|style="color:#BBB"| 5.61 × 10<sup>−11</sup> | |||
|- | |||
|scope="row"| {{0|1.0 ×}} 10<sup>−2</sup> | |||
| 4.92 | |||
|style="color:#000"| 3.36 × 10<sup>−{{0}}4</sup> | |||
|style="color:#666"| 5.71 × 10<sup>−{{0}}7</sup> | |||
|style="color:#666"| 1.19 × 10<sup>−{{0}}5</sup> | |||
|style="color:#BBB"| 5.61 × 10<sup>−11</sup> | |||
|- | |||
|scope="row"| {{0|1.0 ×}} 10<sup>−1</sup> | |||
| 4.42 | |||
|style="color:#000"| 3.36 × 10<sup>−{{0}}3</sup> | |||
|style="color:#666"| 5.71 × 10<sup>−{{0}}6</sup> | |||
|style="color:#666"| 3.78 × 10<sup>−{{0}}5</sup> | |||
|style="color:#BBB"| 5.61 × 10<sup>−11</sup> | |||
|- | |||
|scope="row"| {{0|1.0 ×}} 10<sup>{{0|+}}0</sup> | |||
| 3.92 | |||
|style="color:#000"| 3.36 × 10<sup>−{{0}}2</sup> | |||
|style="color:#666"| 5.71 × 10<sup>−{{0}}5</sup> | |||
|style="color:#666"| 1.20 × 10<sup>−{{0}}4</sup> | |||
|style="color:#BBB"| 5.61 × 10<sup>−11</sup> | |||
|-style="background-color:#AFF" | |||
|scope="row"| {{0|}}2.5 × 10<sup>{{0|+}}0</sup> | |||
| 3.72 | |||
|style="color:#000"| 8.40 × 10<sup>−{{0}}2</sup> | |||
|style="color:#666"| 1.43 × 10<sup>−{{0}}4</sup> | |||
|style="color:#666"| 1.89 × 10<sup>−{{0}}4</sup> | |||
|style="color:#BBB"| 5.61 × 10<sup>−11</sup> | |||
|- | |||
|scope="row"| {{0|1.0 ×}} 10<sup>{{0|+}}1</sup> | |||
| 3.42 | |||
|style="color:#000"| 3.36 × 10<sup>−{{0}}1</sup> | |||
|style="color:#000"| 5.71 × 10<sup>−{{0}}4</sup> | |||
|style="color:#666"| 3.78 × 10<sup>−{{0}}4</sup> | |||
|style="color:#BBB"| 5.61 × 10<sup>−11</sup> | |||
|} | |||
* We see that in the total range of pressure, the pH is always largely lower than pKa<sub>2</sub> so that the CO<sub>3</sub><sup>2−</sup> concentration is always negligible with respect to HCO<sub>3</sub><sup>−</sup> concentration. In fact CO<sub>3</sub><sup>2−</sup> plays no quantitative role in the present calculation (see remark below). | |||
* For vanishing <math>\scriptstyle p_{CO_2}</math>, the pH is close to the one of pure water (pH = 7) and the dissolved carbon is essentially in the HCO<sub>3</sub><sup>−</sup> form. | |||
* For normal atmospheric conditions (<math>\scriptstyle p_{CO_2}=3.5\times 10^{-4}</math> atm), we get a slightly acid solution (p''H'' = 5.7) and the dissolved carbon is now essentially in the CO<sub>2</sub> form. From this pressure on, [OH<sup>−</sup>] becomes also negligible so that the ionized part of the solution is now an equimolar mixture of H<sup>+</sup> and HCO<sub>3</sub><sup>−</sup>. | |||
* For a CO<sub>2</sub> pressure typical of the one in soda drink bottles (<math>\scriptstyle p_{CO_2}</math> ~ 2.5 atm), we get a relatively acid medium (p''H'' = 3.7) with a high concentration of dissolved CO<sub>2</sub>. These features contribute to the sour and sparkling taste of these drinks. | |||
* Between 2.5 and 10 atm, the pH crosses the pKa<sub>1</sub> value (3.60) giving a dominant H<sub>2</sub>CO<sub>3</sub> concentration (with respect to HCO<sub>3</sub><sup>−</sup>) at high pressures. | |||
* A plot of the equilibrium concentrations of these different forms of [[total inorganic carbon|dissolved inorganic carbon]] (and which species is dominant), as a function of the pH of the solution, is known as a [[Bjerrum plot]]. | |||
'''Remark''' | |||
: As noted above, [CO<sub>3</sub><sup>2−</sup>] may be neglected for this specific problem, resulting in the following very precise analytical expression for [H<sup>+</sup>]: | |||
: <math>\scriptstyle[H^+] \simeq \left( 10^{-14}+\frac {K_hK_{a1}}{k_\mathrm{H}} p_{CO_2}\right)^{1/2}</math> | |||
==Spectroscopic studies of carbonic acid== | |||
Theoretical calculations show that the presence of even a single molecule of water causes carbonic acid to revert to carbon dioxide and water. In the absence of water, the dissociation of gaseous carbonic acid is predicted to be very slow, with a [[half-life]] of 180,000 years.<ref name="on_the_surprising">{{cite journal | last1 = Loerting | first1 = T. | last2 = Tautermann | first2 = C. | last3 = Kroemer | first3 = R.T. | last4 = Kohl | first4 = I. | last5 = Hallbrucker | first5 = E. | last6 = Mayer | first6 = A. | last7 = Liedl | first7 = K. R. | |||
| title = On the Surprising Kinetic Stability of Carbonic Acid | journal =[[Angew. Chem. Int. Ed.]] | volume = 39 | pages = 891–895 | year = 2001 | doi = 10.1002/(SICI)1521-3773(20000303)39:5<891::AID-ANIE891>3.0.CO;2-E | pmid=10760883 | issue = 5}}</ref> | |||
It has long been recognized that pure carbonic acid cannot be obtained at room temperatures (about 20 °C or about 70 °F). It can be generated by exposing a frozen mixture of water and carbon dioxide to high-energy radiation, and then warming to remove the excess water. The carbonic acid that remained was characterized by infrared spectroscopy. The fact that the carbonic acid was prepared by irradiating a solid H<sub>2</sub>O + CO<sub>2</sub> mixture may suggest that H<sub>2</sub>CO<sub>3</sub> might be found in outer space, where frozen ices of H<sub>2</sub>O and CO<sub>2</sub> are common, as are cosmic rays and ultraviolet light, to help them react.<ref name="on_the_surprising"/> The same carbonic acid polymorph (denoted ''beta''-carbonic acid) was prepared by heating alternating layers of glassy aqueous solutions of bicarbonate and acid ''in vacuo'', which causes protonation of bicarbonate, followed by removal of the solvent. ''Alpha''-carbonic acid was prepared by the same technique using methanol rather than water as a solvent. | |||
==See also== | |||
* [[Carbonated water]] | |||
* [[Ocean acidification]] | |||
* [[Carbon dioxide]] | |||
* [[Dihydroxymethylidene]] (carbonous acid) | |||
== References == | |||
{{Reflist}} | |||
==Further reading== | |||
*{{cite journal | last1 = Welch | first1 = M. J. | last2 = Lifton | first2 = J. F. | |||
| last3 = Seck | first3 = J. A. | journal = [[J. Phys. Chem.]] | volume = 73 | issue = 335 | year = 1969 | doi = 10.1021/j100844a033 | title = Tracer studies with radioactive oxygen-15. Exchange between carbon dioxide and water | pages = 3351}} | |||
*{{cite book | author=Jolly, W. L. | title=Modern Inorganic Chemistry (2nd Edn.) | location=New York | publisher=McGraw-Hill | year=1991 | isbn=0-07-112651-1}} | |||
*{{cite journal | last1 = Moore | first1 = M. H. | last2 = Khanna | first2 = R. | title = Infrared and Mass Spectral Studies of Proton Irradiated H2O+Co2 Ice: Evidence for Carbonic Acid Ice: Evidence for Carbonic Acid | journal = [[Spectrochimica Acta]] | volume = 47A | doi =10.1016/0584-8539(91)80097-3 | pages = 255–262 | year = 1991 | issue = 2}} | |||
* {{cite journal | last1 = W. Hage | first1 = K. R. Liedl | last2 = Liedl | first2 = E. | title = Carbonic Acid in the Gas Phase and Its Astrophysical Relevance | journal = [[Science (journal)|Science]] | volume = 279 | pages = 1332–1335 | |||
| year = 1998 | doi = 10.1126/science.279.5355.1332 | pmid = 9478889 | last3 = Hallbrucker | first3 = A | last4 = Mayer | first4 = E | issue = 5355}} | |||
* {{cite journal | |||
| last1 = Hage | first1 = W. | last2 = Hallbrucker | first2 = A. | last3 = Mayer | first3 = E. | title = Carbonic Acid: Synthesis by Protonation of Bicarbonate and Ftir Spectroscopic Characterization Via a New Cryogenic Technique | journal = [[J. Am. Chem. Soc.]] | volume = 115 | pages = 8427–8431 | doi = 10.1021/ja00071a061 | year = 1993 | |||
| issue = 18}} | |||
* {{cite journal | last1 = Hage | first1 = W. | last2 = Hallbrucker | first2 = A. | |||
| last3 = Mayer | first3 = E. | title = A Polymorph of Carbonic Acid and Its Possible Astrophysical Relevance | journal = [[J. Chem. Soc. Farad. Trans.]] | volume = 91 | pages = 2823–2826 | doi = 10.1039/ft9959102823 | year = 1995 | issue = 17}} | |||
== External links == | |||
* [http://www.newton.dep.anl.gov/askasci/chem99/chem99661.htm Ask a Scientist: Carbonic Acid Decomposition] | |||
* [http://www.wiley-vch.de/vch/journals/2002/press/200005press.html Why was the existence of carbonic acid unfairly doubted for so long?] | |||
*[http://www2.iq.usp.br/docente/gutz/Curtipot_.html Carbonic acid/bicarbonate/carbonate equilibrium in water: pH of solutions, buffer capacity, titration and species distribution vs. pH computed with a free spreadsheet] | |||
*[http://www.chem.usu.edu/~sbialkow/Classes/3600/Overheads/Carbonate/CO2.html How to calculate concentration of Carbonic Acid in Water] | |||
{{Hydrogen compounds}} | |||
{{Oxides of carbon}} | |||
{{DEFAULTSORT:Carbonic Acid}} | |||
[[Category:Acids]] | |||
[[Category:Carbonates]] |
Revision as of 05:25, 30 January 2014
- Not to be confused with carbolic acid, an antiquated name for phenol.
- Carbonic acid is also an archaic name for carbon dioxide.
Carbonic acid is the chemical compound with the formula H2CO3 (equivalently OC(OH)2). It is also a name sometimes given to solutions of carbon dioxide in water (carbonated water), because such solutions contain small amounts of H2CO3. Carbonic acid, which is a weak acid, forms two kinds of salts, the carbonates and the bicarbonates. In geology, Carbonic acid causes limestone to dissolve producing calcium bicarbonate which leads to many limestone features such as stalactites and stalagmites .
Chemical equilibrium
When carbon dioxide dissolves in water it exists in chemical equilibrium producing carbonic acid:[1]
- CO2 + H2O Template:Eqm H2CO3
The hydration equilibrium constant at 25°C is called Kh, which in the case of carbonic acid is [H2CO3]/[CO2] ≈ 1.7×10−3 in pure water[2] and ≈ 1.2×10−3 in seawater.[3] Hence, the majority of the carbon dioxide is not converted into carbonic acid, remaining as CO2 molecules. In the absence of a catalyst, the equilibrium is reached quite slowly. The rate constants are 0.039 s−1 for the forward reaction (CO2 + H2O → H2CO3) and 23 s−1 for the reverse reaction (H2CO3 → CO2 + H2O). Carbonic acid is used in the making of soft drinks, inexpensive and artificially carbonated sparkling wines, and other bubbly drinks. The addition of two equivalents of water to CO2 would give orthocarbonic acid, C(OH)4, which exists only in minute amounts in aqueous solution.
Addition of base to an excess of carbonic acid gives bicarbonate. With excess base, carbonic acid reacts to give carbonate salts.
Role of carbonic acid in blood
Carbonic acid is an intermediate step in the transport of CO2 out of the body via respiratory gas exchange. The hydration reaction of CO2 is generally very slow in the absence of a catalyst, but red blood cells contain carbonic anhydrase, which both increases the reaction rate and dissociates a hydrogen ion (H+) from the resulting carbonic acid, leaving bicarbonate (HCO3−) dissolved in the blood plasma. This catalysed reaction is reversed in the lungs, where it converts the bicarbonate back into CO2 and allows it to be expelled. This equilibration plays an important role as a buffer in mammalian blood.[4]
<Ocean>...</Ocean>
Role of carbonic acid in ocean chemistry
The oceans of the world have absorbed almost half of the CO2 emitted by humans from the burning of fossil fuels.[5] The extra dissolved carbon dioxide has caused the ocean's average surface pH to shift by about 0.1 unit from pre-industrial levels.[6] This process is known as ocean acidification.[7]
Acidity of carbonic acid
Carbonic acid is one of the polyprotic acids: It is diprotic - it has two protons, which may dissociate from the parent molecule. Thus, there are two dissociation constants, the first one for the dissociation into the bicarbonate (also called hydrogen carbonate) ion HCO3−:
- H2CO3 Template:Eqm HCO3− + H+
- Ka1 = 2.5×10−4 mol/litre; pKa1 = 3.6 at 25 °C.[1]
Care must be taken when quoting and using the first dissociation constant of carbonic acid. In aqueous solution, carbonic acid exists in equilibrium with carbon dioxide, and the concentration of H2CO3 is much lower than the concentration of CO2. In many analyses, H2CO3 includes dissolved CO2 (referred to as CO2(aq)), H2CO3* is used to represent the two species when writing the aqueous chemical equilibrium equation. The equation may be rewritten as follows:[1]
- H2CO3* Template:Eqm HCO3− + H+
- Ka(app) = 4.6×10−7 mol/litre ; pK(app) = 6.3 at 25 °C and Ionic Strength = 0.0
Whereas this apparent pKa is quoted as the dissociation constant of carbonic acid, it is ambiguous: it might better be referred to as the acidity constant of dissolved carbon dioxide, as it is particularly useful for calculating the pH of CO2-containing solutions. A similar situation applies to sulfurous acid (H2SO3), which exists in equilibrium with substantial amounts of unhydrated sulfur dioxide.
The second constant is for the dissociation of the bicarbonate ion into the carbonate ion CO32−:
- HCO3− Template:Eqm CO32− + H+
- Ka2 = 4.69×10−11 mol/litre ; pKa2 = 10.329 at 25 °C and Ionic Strength = 0.0
pH and composition of carbonic acid solutions
At a given temperature, the composition of a pure carbonic acid solution (or of a pure CO2 solution) is completely determined by the partial pressure of carbon dioxide above the solution. To calculate this composition, account must be taken of the above equilibria between the three different carbonate forms (H2CO3, HCO3− and CO32−) as well as of the hydration equilibrium between dissolved CO2 and H2CO3 with constant (see above) and of the following equilibrium between the dissolved CO2 and the gaseous CO2 above the solution:
- CO2(gas) Template:Eqm CO2(dissolved) with where kH=29.76 atm/(mol/L) at 25 °C (Henry constant)
The corresponding equilibrium equations together with the relation and the charge neutrality condition result in six equations for the six unknowns [CO2], [H2CO3], [H+], [OH−], [HCO3−] and [CO32−], showing that the composition of the solution is fully determined by . The equation obtained for [H+] is a cubic whose numerical solution yields the following values for the pH and the different species concentrations:
(atm) |
pH | [CO2] (mol/L) |
[H2CO3] (mol/L) |
[HCO3−] (mol/L) |
[CO32−] (mol/L) |
---|---|---|---|---|---|
Template:0 10−8 | 7.00 | 3.36 × 10−10 | 5.71 × 10−13 | 1.42 × 10−Template:09 | 7.90 × 10−13 |
Template:0 10−7 | 6.94 | 3.36 × 10−Template:09 | 5.71 × 10−12 | 5.90 × 10−Template:09 | 1.90 × 10−12 |
Template:0 10−6 | 6.81 | 3.36 × 10−Template:08 | 5.71 × 10−11 | 9.16 × 10−Template:08 | 3.30 × 10−11 |
Template:0 10−5 | 6.42 | 3.36 × 10−Template:07 | 5.71 × 10−10 | 3.78 × 10−Template:07 | 4.53 × 10−11 |
Template:0 10−4 | 5.92 | 3.36 × 10−Template:06 | 5.71 × 10−Template:09 | 1.19 × 10−Template:06 | 5.57 × 10−11 |
Template:03.5 × 10−4 | 5.65 | 1.18 × 10−Template:05 | 2.00 × 10−Template:08 | 2.23 × 10−Template:06 | 5.60 × 10−11 |
Template:0 10−3 | 5.42 | 3.36 × 10−Template:05 | 5.71 × 10−Template:08 | 3.78 × 10−Template:06 | 5.61 × 10−11 |
Template:0 10−2 | 4.92 | 3.36 × 10−Template:04 | 5.71 × 10−Template:07 | 1.19 × 10−Template:05 | 5.61 × 10−11 |
Template:0 10−1 | 4.42 | 3.36 × 10−Template:03 | 5.71 × 10−Template:06 | 3.78 × 10−Template:05 | 5.61 × 10−11 |
Template:0 10Template:00 | 3.92 | 3.36 × 10−Template:02 | 5.71 × 10−Template:05 | 1.20 × 10−Template:04 | 5.61 × 10−11 |
Template:02.5 × 10Template:00 | 3.72 | 8.40 × 10−Template:02 | 1.43 × 10−Template:04 | 1.89 × 10−Template:04 | 5.61 × 10−11 |
Template:0 10Template:01 | 3.42 | 3.36 × 10−Template:01 | 5.71 × 10−Template:04 | 3.78 × 10−Template:04 | 5.61 × 10−11 |
- We see that in the total range of pressure, the pH is always largely lower than pKa2 so that the CO32− concentration is always negligible with respect to HCO3− concentration. In fact CO32− plays no quantitative role in the present calculation (see remark below).
- For vanishing , the pH is close to the one of pure water (pH = 7) and the dissolved carbon is essentially in the HCO3− form.
- For normal atmospheric conditions ( atm), we get a slightly acid solution (pH = 5.7) and the dissolved carbon is now essentially in the CO2 form. From this pressure on, [OH−] becomes also negligible so that the ionized part of the solution is now an equimolar mixture of H+ and HCO3−.
- For a CO2 pressure typical of the one in soda drink bottles ( ~ 2.5 atm), we get a relatively acid medium (pH = 3.7) with a high concentration of dissolved CO2. These features contribute to the sour and sparkling taste of these drinks.
- Between 2.5 and 10 atm, the pH crosses the pKa1 value (3.60) giving a dominant H2CO3 concentration (with respect to HCO3−) at high pressures.
- A plot of the equilibrium concentrations of these different forms of dissolved inorganic carbon (and which species is dominant), as a function of the pH of the solution, is known as a Bjerrum plot.
Remark
- As noted above, [CO32−] may be neglected for this specific problem, resulting in the following very precise analytical expression for [H+]:
Spectroscopic studies of carbonic acid
Theoretical calculations show that the presence of even a single molecule of water causes carbonic acid to revert to carbon dioxide and water. In the absence of water, the dissociation of gaseous carbonic acid is predicted to be very slow, with a half-life of 180,000 years.[8]
It has long been recognized that pure carbonic acid cannot be obtained at room temperatures (about 20 °C or about 70 °F). It can be generated by exposing a frozen mixture of water and carbon dioxide to high-energy radiation, and then warming to remove the excess water. The carbonic acid that remained was characterized by infrared spectroscopy. The fact that the carbonic acid was prepared by irradiating a solid H2O + CO2 mixture may suggest that H2CO3 might be found in outer space, where frozen ices of H2O and CO2 are common, as are cosmic rays and ultraviolet light, to help them react.[8] The same carbonic acid polymorph (denoted beta-carbonic acid) was prepared by heating alternating layers of glassy aqueous solutions of bicarbonate and acid in vacuo, which causes protonation of bicarbonate, followed by removal of the solvent. Alpha-carbonic acid was prepared by the same technique using methanol rather than water as a solvent.
See also
- Carbonated water
- Ocean acidification
- Carbon dioxide
- Dihydroxymethylidene (carbonous acid)
References
43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.
Further reading
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Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang - 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.
My blog: http://www.primaboinca.com/view_profile.php?userid=5889534 - One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang - One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang - One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang - One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang
External links
- Ask a Scientist: Carbonic Acid Decomposition
- Why was the existence of carbonic acid unfairly doubted for so long?
- Carbonic acid/bicarbonate/carbonate equilibrium in water: pH of solutions, buffer capacity, titration and species distribution vs. pH computed with a free spreadsheet
- How to calculate concentration of Carbonic Acid in Water
Template:Hydrogen compounds Template:Oxides of carbon
- ↑ 1.0 1.1 1.2 Welcome to NewLaunch101.com. Buying a property is rarely a straightforward decision in life, and we do perceive that. To be able to help buyers/consumers out to be more conscious of the current market situation and the accessible options to select from, that is why NewLaunch101.com was created.
Government wealth taxation generally takes the form of both taxes on capital positive factors and/or estate duties. Any tax coverage must strike a stability between socially-acceptable wealth creation and extreme wealth accumulation. Bangkok is Thailand's top tourist destination and it is an awesome city. However should you just like the seashore, the seaside resort of Hua Hin is simply three hours by car from Bangkok. This picturesque town has great shopping, cool eating places, relaxing cafés, and contemporary seafood you could purchase right off the boat. There may be also mountain climbing and camping, world-class golf programs, and delightful beaches and islands on your doorstep. From Cambodia to Thailand-Take pleasure in a Low Cost of Living in Asia ABSD for Residential Properties Declaration For m (one hundred seventy five KB)
The truth is, things can get pretty chaotic, with buyers clamouring to be the first to e book their models. For some Singapore property gross sales, there might even be overnight queues. To keep away from that, developers may select to use balloting as a substitute of queueing for determining who will get to enter the showflat first. a) SSD at 15% if the property is offered within the first 12 months of purchase, i.e. the property is held for one year or much less from the date of purchase b) SSD at 10% if the property is sold in the second yr of buy, i.e. the property is held for multiple yr and as much as two years from the date of buy. Any non-standard clauses from the Sale & Purchase Settlement (the ultimate contract for the sale - see under); The sale that price ready for
BG Tan has had a distinguished profession with the SAF for over 26 years, during which he held important command and staff appointments requiring strong leadership, analytical, and organisational abilities. These included Future Methods Architect, Commander, third Singapore Division and Assistant Chief of the General Employees (Intelligence). BG Tan will retire from the SAF and return to the Administrative Service with effect from 1 June 2011. In Singapore, a developer who needs to promote models in an uncompleted growth, such as one that has simply began building, must first obtain a Sale License to do so. The Venue Residences to Stay, Store and Dine, a luxurious mixeddevelopment by CDL in preparation for launch now. Looking for registrationof curiosity.
Nevertheless, the newest cooling measure s seemed to have really taken the wind out from the sails of the property market. With a tightened loan to worth (LTV) framework and the introduction of the Total Debt Servicing Ratio (TDSR), speculators and investors not discover it as enticing to simply purchase into any property for a quick profit. Thus, property costs and transaction volumes have started to slip. The new property tax schedule for owner-occupied houses will be certain that most retirees will end up paying decrease property taxes, he added. Imposed on Everlasting Residents (PRs) purchasing their first residential property and on Singaporeans buying their second residential property. Citizenship ABSD Fee on Why do we solely have property tax as a wealth tax?
Rising workplace sector leads real property market efficiency, whereas prime retail and enterprise park segments average and residential sector continues in decline Latest knowledge from Actual Capital Analytics (RCA) exhibits real property advisory firm suggested on the most offers by value within the area in 2013 A substitute for estate duties is an inheritance tax, which assesses beneficiaries rather than the property of the deceased, and may be simpler to manage and accumulate, notably when assets are held overseas. There isn't a purpose for an organization or particular person not to buy. Don't ask me why they pay lease. A few of them pay even rent to overseas homeowners or overseas owned firms. District 18, 999 yr LH residence Residential items & fifty seven business models Posted by Edison Foo July 3, 2013
Singapore new launches, new Landed Home, Cluster Home, Apartment, House, Business Industrial Properties for Sale New Initiatives Launched ! Simply click on > B uying E nquiry just under this annoucement to register your interest with us for selection models booking. You'll be able to obtain Website Plans and Flooring Plans from Learn More under singapore new condo launches Launch Initiatives. However, for HDB upgraders getting another HDB flat or HDB government condominium, the monthly cost under the existing property could be excluded from the debt-servicing calculation. That is provided the present property is present process the sale course of, and the borrowers don't own every other property (including joint ownership with others) or have any other property loans to their title. RiverParc EC @ Punggol - ↑ Housecroft and Sharpe, Inorganic Chemistry, 2nd ed, Prentice-Pearson-Hall 2005, p.368.
- ↑ One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang - ↑ "excretion." Encyclopædia Britannica. Encyclopædia Britannica Ultimate Reference Suite. Chicago: Encyclopædia Britannica, 2010.
- ↑ One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang Template:Dead link - ↑ Template:Cite web
- ↑ National Research Council. "Summary." Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean. Washington, DC: The National Academies Press, 2010. 1. Print.
- ↑ 8.0 8.1 One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang