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3 – meaning the concentration of carbonate expressed as if calcium carbonate were the sole source of carbonate ions. An aqueous solution containing 120 mg NaHCO 3 (baking soda) per litre of water will contain 1.4285 mmol/l of bicarbonate, since the molar mass of baking soda is 84.007 g/mol. This is equivalent in carbonate hardness to a ...
The carbon dioxide in the air reacts with the alkali in the cement and makes the pore water more acidic, thus lowering the pH. Carbon dioxide will start to carbonatate the cement in the concrete from the moment the object is made. This carbonatation process will start at the surface, then slowly moves deeper and deeper into the concrete.
2 increases the concrete carbonation rate. When the carbonation front reaches the steel reinforcements (rebar), the pH of the concrete pore water at the steel surface decreases. At a pH value lower than 10.5, the carbon steel is no longuer passivated by an alkaline pH and starts to corrode ( general corrosion ).
In even a slight presence of water, carbonic acid dehydrates to carbon dioxide and water, which then catalyzes further decomposition. [6] For this reason, carbon dioxide can be considered the carbonic acid anhydride. The hydration equilibrium constant at 25 °C is [H 2 CO 3]/[CO 2] ≈ 1.7×10 −3 in pure water [12] and ≈ 1.2×10 −3 in ...
Aqueous carbon dioxide reacts with water to form carbonic acid which is very unstable and will dissociate rapidly into hydronium and bicarbonate. Therefore, in seawater, dissolved inorganic carbon is commonly referred to as the collection of bicarbonate, carbonate ions, and dissolved carbon dioxide (CO 2, H 2 CO 3, HCO − 3, CO 2− 3).
In mammalian physiology, transport of carbon dioxide to the lungs involves a carbonation reaction catalyzed by the enzyme carbonic anhydrase. In the absence of such catalysts, carbon dioxide cannot be expelled sufficient rate to support metabolic needs. The enzyme harbors a zinc aquo complex, which captures carbon dioxide to give a zinc ...
Modern carbonated water is made by injecting pressurized carbon dioxide into water. [36] The pressure increases the solubility and allows more carbon dioxide to dissolve than would be possible under standard atmospheric pressure. When the bottle is opened, the pressure is released, allowing gas to exit the solution, forming the characteristic ...
Biomass is heated together with water to 180 °C (356 °F) in a pressure vessel, in particular vegetable material (in the following reaction equation, simplified as sugar with the formula C 6 H 12 O 6). The pressure rises to about 1 megapascal (150 psi). During the reaction, oxonium ions are also formed which reduce the pH to pH 5 and lower.