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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.
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 ...
However, certain substances, water for example, contain unique angular structures at the molecular level. As such, when these substances reach temperatures just above their freezing point, they begin to expand, since the angle of the bonds prevent the molecules from tightly fitting together, resulting in more empty space between the molecules ...
[1] 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.
– divalent (SO 2− 4, CO 2− 3 …) with y = 1, or; – monovalent (OH −, Cl − …) with y = 2. n represents the number of water molecules in the hydrate and may be comprised between 13 and 19. [1] AFm form inter alia when tricalcium aluminate 3CaO·Al 2 O 3, or C 3 A in CCN, reacts with dissolved calcium sulfate (CaSO 4), or calcium ...
In more acid conditions, aqueous carbon dioxide, CO 2 (aq), is the main form, which, with water, H 2 O, is in equilibrium with carbonic acid – the equilibrium lies strongly towards carbon dioxide. Thus sodium carbonate is basic, sodium bicarbonate is weakly basic, while carbon dioxide itself is a weak acid.
Carbonation is the chemical reaction of carbon dioxide to give carbonates, bicarbonates, and carbonic acid. [1] In chemistry, the term is sometimes used in place of carboxylation, which refers to the formation of carboxylic acids. In inorganic chemistry and geology, carbonation is common.
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 solution containing 0.71423 mmol/L of (calcium) carbonate, or 71.485 mg/L of calcium carbonate (molar mass 100.09 g/mol).