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Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO 4 ·2H 2 O. [4] It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster , drywall and blackboard or sidewalk chalk .
Alteration of hardened cement paste composition, with monosulfate aluminates phase converting to ettringite and, in later stages, gypsum formation. The necessary additional calcium is provided by the calcium hydroxide and calcium silicate hydrate in the cement paste; The effect of these changes is an overall loss of concrete strength.
2)) present in the hardened cement paste to give gypsum: H 2 SO 4 + Ca(OH) 2 → CaSO 4 · 2H 2 O. When concrete is carbonated by atmospheric carbon dioxide (CO 2), or if limestone aggregates are used in concrete, H 2 SO 4 reacts with calcite (CaCO 3) and water to also form gypsum while releasing CO 2 back to the atmosphere: H 2 SO 4 + CaCO 3 ...
With judicious heating, gypsum converts to the partially dehydrated mineral called bassanite or plaster of Paris. This material has the formula CaSO 4 ·( n H 2 O), where 0.5 ≤ n ≤ 0.8. [ 8 ] Temperatures between 100 and 150 °C (212–302 °F) are required to drive off the water within its structure.
Gypsum (CaSO 4.2H 2 O) is a hydrate solid that, in a sufficiently dry environment, will give up its water to the gas phase and form anhydrite (CaSO 4). Copper(II) sulfate (bluestone) (CuSO 4 .5H 2 O) is a blue crystalline solid that when exposed to air, slowly loses water of crystallization from its surface to form a white layer of anhydrous ...
Move over, Wordle and Connections—there's a new NYT word game in town! The New York Times' recent game, "Strands," is becoming more and more popular as another daily activity fans can find on ...
Rainwater easily dissolves soluble minerals, such as halite or gypsum, but can also dissolve highly resistant minerals such as quartz, given sufficient time. [25] Water breaks the bonds between atoms in the crystal: [26] The overall reaction for dissolution of quartz is SiO 2 + 2 H 2 O → H 4 SiO 4. The dissolved quartz takes the form of ...
Cage-Free. As the label implies, the hens that produce cage-free eggs, do indeed live outside of cages.However, that does not mean that they have room to roam around. "They are often kept indoors ...