Search results
Results from the WOW.Com Content Network
Anhydrous aluminium chloride is hygroscopic, having a very pronounced affinity for water. It fumes in moist air and hisses when mixed with liquid water as the Cl − ligands are displaced with H 2 O molecules to form the hexahydrate [Al(H 2 O) 6]Cl 3. The anhydrous phase cannot be regained on heating the hexahydrate.
In oxygenic photosynthesis, water (H 2 O) serves as a substrate for photolysis resulting in the generation of diatomic oxygen (O 2). This is the process which returns oxygen to Earth's atmosphere. Photolysis of water occurs in the thylakoids of cyanobacteria and the chloroplasts of green algae and plants. [3]
The process of oxidizing two molecules of water to form an oxygen molecule requires four electrons. The water molecules that are oxidized in the manganese center are the source of the electrons that reduce the two molecules of Q to QH 2. To date, this water splitting catalytic center has not been reproduced by any man-made catalyst.
In chemistry, water(s) of crystallization or water(s) of hydration are water molecules that are present inside crystals. Water is often incorporated in the formation of crystals from aqueous solutions . [ 1 ]
The S–I cycle consists of three chemical reactions whose net reactant is water and whose net products are hydrogen and oxygen. All other chemicals are recycled. The S–I process requires an efficient source of heat. More than 352 thermochemical cycles have been described for water splitting by thermolysis. [21]
To clarify that it is the gaseous form that is being referred to, the term anhydrous is prefixed to the name of the substance: Gaseous ammonia is generally referred to as anhydrous ammonia, to distinguish it from its solution in water, household ammonia solution, also known as ammonium hydroxide.
For similar reasons, anhydrous aluminium salts cannot be made by heating their "hydrates": hydrated aluminium chloride is in fact not AlCl 3 ·6H 2 O but [Al(H 2 O) 6]Cl 3, and the Al–O bonds are so strong that heating is not sufficient to break them and form Al–Cl bonds instead: [2] 2[Al(H 2 O) 6]Cl 3 Al 2 O 3 + 6 HCl + 9 H 2 O
The Claisen rearrangement is a powerful carbon–carbon bond-forming chemical reaction discovered by Rainer Ludwig Claisen. [1] The heating of an allyl vinyl ether will initiate a [3,3]-sigmatropic rearrangement to give a γ,δ-unsaturated carbonyl, driven by exergonically favored carbonyl CO bond formation with Δ(Δ f H) ca. −25 kcal/mol (−100 kJ/mol).