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Carbon dioxide, a by-product of cellular respiration, is dissolved in the blood. From the blood it is taken up by red blood cells and converted to carbonic acid by the carbonate buffer system. Most carbonic acid then dissociates to bicarbonate and hydrogen ions. One of the buffer systems present in the body is the blood plasma buffering system.
Example Bjerrum plot: Change in carbonate system of seawater from ocean acidification.. A Bjerrum plot (named after Niels Bjerrum), sometimes also known as a Sillén diagram (after Lars Gunnar Sillén), or a Hägg diagram (after Gunnar Hägg) [1] is a graph of the concentrations of the different species of a polyprotic acid in a solution, as a function of pH, [2] when the solution is at ...
When the total CO 2 content is significant, as in natural waters and alkaline effluents, two or three inflections can be seen in the pH-volume curves owing to buffering by higher concentrations of bicarbonate and carbonate. As discussed by Stumm and Morgan (1981), the analysis of such waters can use up to six Gran plots from a single titration ...
Sodium carbonate is obtained as three hydrates and as the anhydrous salt: sodium carbonate decahydrate , Na 2 CO 3 ·10H 2 O, which readily effloresces to form the monohydrate. sodium carbonate heptahydrate (not known in mineral form), Na 2 CO 3 ·7H 2 O. sodium carbonate monohydrate (thermonatrite), Na 2 CO 3 ·H 2 O. Also known as crystal ...
Carbonate speciation in seawater (ionic strength 0.7 mol/dm 3). The expected change shown is due to the current anthropogenic increase in atmospheric carbon dioxide concentration. The Bjerrum plot shows typical equilibrium concentrations, in solution, in seawater, of carbon dioxide and the various species derived from it, as a function of pH.
k H CO 2 is a constant including the solubility of carbon dioxide in blood. k H CO 2 is approximately 0.03 (mmol/L)/mmHg; p CO 2 is the partial pressure of carbon dioxide in the blood; Combining these equations results in the following equation relating the pH of blood to the concentration of bicarbonate and the partial pressure of carbon ...
Buffer capacity falls to 33% of the maximum value at pH = pK a ± 1, to 10% at pH = pK a ± 1.5 and to 1% at pH = pK a ± 2. For this reason the most useful range is approximately pK a ± 1. When choosing a buffer for use at a specific pH, it should have a pK a value as close as possible to that pH. [2]
Conversely, when pH = pK a, the concentration of HA is equal to the concentration of A −. The buffer region extends over the approximate range pK a ± 2. Buffering is weak outside the range pK a ± 1. At pH ≤ pK a − 2 the substance is said to be fully protonated and at pH ≥ pK a + 2 it is fully dissociated (deprotonated).