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The overall chemical reaction is: CO 2 + Ca(OH) 2 → CaCO 3 + H 2 O + heat (in the presence of water) Each mole of CO 2 (44 g) reacts with one mole of calcium hydroxide (74 g) and produces one mole of water (18 g). The reaction can be considered as a strong-base-catalysed, water-facilitated reaction. [5]
Carbonatation is a slow process that occurs in concrete where lime (CaO, or Ca(OH) 2 ) in the cement reacts with carbon dioxide (CO 2) from the air and forms calcium carbonate. The water in the pores of Portland cement concrete is normally alkaline with a pH in the range of 12.5 to 13.5.
Its solubility product K sp of 5.02 × 10 −6 at 25 °C, [1] its dissociation in water is large enough that its solutions are basic according to the following dissolution reaction: Ca(OH) 2 → Ca 2+ + 2 OH −. The solubility is affected by the common-ion effect. Its solubility drastically decreases upon addition of hydroxide or calcium sources.
A solution or suspension of calcium hydroxide is known as limewater and can be used to test for the weak acid carbon dioxide. The reaction Ca(OH) 2 + CO 2 ⇌ Ca 2+ + HCO − 3 + OH − illustrates the basicity of calcium hydroxide. Soda lime, which is a mixture of the strong bases NaOH and KOH with Ca(OH) 2, is used as a CO 2 absorbent.
CaO (s) + H 2 O (l) ⇌ Ca(OH) 2 (aq) (ΔH r = −63.7 kJ/mol of CaO) As it hydrates, an exothermic reaction results and the solid puffs up. The hydrate can be reconverted to quicklime by removing the water by heating it to redness to reverse the hydration reaction.
CaH 2: −186.2 Calcium hydroxide: Solid Ca(OH) 2: −986.09 Calcium hydroxide: Aqueous Ca(OH) 2: −1002.82 Calcium oxide: Solid CaO −635.09 Calcium sulfate: Solid CaSO 4: −1434.52 Calcium sulfide: Solid CaS −482.4 Wollastonite: Solid CaSiO 3: −1630 Carbon Solid C 0 Carbon Solid C 1.9 Carbon: Gas C 716.67 Carbon dioxide: Gas CO 2: − ...
A carbon dioxide scrubber is a piece of equipment that absorbs carbon dioxide (CO 2). ... → Ca(OH) 2 (s) ... + 3 H 2 O (g) The net reaction being:
Ca(OH) 2 or CaO · H 2 O: Calcium hydroxide (portlandite) C-S-H: 0.6–2.0 CaO · SiO 2 · 0.9–2.5 H 2 O, with variable composition within this range, and often also incorporating partial substitution of Al for Si: Calcium silicate hydrate: C-A-H: Phase more complex than C-S-H: Calcium aluminate hydrate C-A-S-H: This is even more complex than ...