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  2. Chemical cycling - Wikipedia

    en.wikipedia.org/wiki/Chemical_cycling

    The lack of a complete carbon cycle including a geochemical carbon cycle, for example, is thought to be a cause of its runaway greenhouse effect, due to the lack of a substantial carbon sink. [4] Sulphur cycles including sulphur oxide cycles also occur, sulphur oxide in the upper atmosphere and results in the presence of sulfuric acid [ 5 ] in ...

  3. Marine biogeochemical cycles - Wikipedia

    en.wikipedia.org/wiki/Marine_biogeochemical_cycles

    Since liquid water flows, ocean waters cycle and flow in currents around the world. Since water easily changes phase, it can be carried into the atmosphere as water vapour or frozen as an iceberg. It can then precipitate or melt to become liquid water again. All marine life is immersed in water, the matrix and womb of life itself. [7]

  4. Oxygen cycle - Wikipedia

    en.wikipedia.org/wiki/Oxygen_cycle

    The word oxygen in the literature typically refers to the most common oxygen allotrope, elemental/diatomic oxygen (O 2), as it is a common product or reactant of many biogeochemical redox reactions within the cycle. [2] Processes within the oxygen cycle are considered to be biological or geological and are evaluated as either a source (O 2 ...

  5. Water splitting - Wikipedia

    en.wikipedia.org/wiki/Water_splitting

    The sulfur–iodine cycle (S–I cycle) is a series of thermochemical processes used to produce hydrogen. 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.

  6. Thermochemical cycle - Wikipedia

    en.wikipedia.org/wiki/Thermochemical_cycle

    In chemistry, thermochemical cycles combine solely heat sources (thermo) with chemical reactions to split water into its hydrogen and oxygen components. [1] The term cycle is used because aside of water, hydrogen and oxygen, the chemical compounds used in these processes are continuously recycled.

  7. Hill reaction - Wikipedia

    en.wikipedia.org/wiki/Hill_reaction

    Hill's finding was that the origin of oxygen in photosynthesis is water (H 2 O) not carbon dioxide (CO 2) as previously believed. Hill's observation of chloroplasts in dark conditions and in the absence of CO 2, showed that the artificial electron acceptor was oxidized but not reduced, terminating the process, but without production of oxygen ...

  8. Lime (material) - Wikipedia

    en.wikipedia.org/wiki/Lime_(material)

    Pure lime is soluble in water containing carbonic acid, a natural, weak acid which is a solution of carbon dioxide in water and acid rain so it will slowly wash away, but this characteristic also produces autogenous or self-healing process where the dissolved lime can flow into cracks in the material and be redeposited, automatically repairing ...

  9. Liquefaction - Wikipedia

    en.wikipedia.org/wiki/Liquefaction

    It occurs both naturally and artificially. As an example of the latter, a "major commercial application of liquefaction is the liquefaction of air to allow separation of the constituents, such as oxygen, nitrogen, and the noble gases." [4] Another is the conversion of solid coal into a liquid form usable as a substitute for liquid fuels. [5]