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  2. Urea cycle - Wikipedia

    en.wikipedia.org/wiki/Urea_cycle

    Urea cycle. The urea cycle (also known as the ornithine cycle) is a cycle of biochemical reactions that produces urea (NH 2) 2 CO from ammonia (NH 3). Animals that use this cycle, mainly amphibians and mammals, are called ureotelic. The urea cycle converts highly toxic ammonia to urea for excretion. [1] This cycle was the first metabolic cycle ...

  3. Haber process - Wikipedia

    en.wikipedia.org/wiki/Haber_process

    The Haber process, [1] also called the Haber–Bosch process, is the main industrial procedure for the production of ammonia. [2][3] It converts atmospheric nitrogen (N 2) to ammonia (NH 3) by a reaction with hydrogen (H 2) using a finely divided iron metal catalyst: This reaction is slightly favorable in terms of enthalpy, but is disfavored in ...

  4. Ammonia - Wikipedia

    en.wikipedia.org/wiki/Ammonia

    Ammonia forms 1:1 adducts with a variety of Lewis acids such as I 2, phenol, and Al(CH 3) 3. Ammonia is a hard base (HSAB theory) and its E & C parameters are E B = 2.31 and C B = 2.04. Its relative donor strength toward a series of acids, versus other Lewis bases, can be illustrated by C-B plots .

  5. Miller–Urey experiment - Wikipedia

    en.wikipedia.org/wiki/Miller–Urey_experiment

    In the original 1952 experiment, methane (CH 4), ammonia (NH 3), and hydrogen (H 2) were all sealed together in a 2:2:1 ratio (1 part H 2) inside a sterile 5-L glass flask connected to a 500-mL flask half-full of water (H 2 O). The gas chamber was intended to represent Earth's prebiotic atmosphere, while the water simulated an ocean. The water ...

  6. Urea - Wikipedia

    en.wikipedia.org/wiki/Urea

    The structure of the molecule of urea is O=C(−NH 2) 2.The urea molecule is planar when in a solid crystal because of sp 2 hybridization of the N orbitals. [8] [9] It is non-planar with C 2 symmetry when in the gas phase [10] or in aqueous solution, [9] with C–N–H and H–N–H bond angles that are intermediate between the trigonal planar angle of 120° and the tetrahedral angle of 109.5°.

  7. Ammonium - Wikipedia

    en.wikipedia.org/wiki/Ammonium

    Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) molecular ion with the chemical formula NH+ 4 or [NH4]+. It is formed by the addition of a proton (a hydrogen nucleus) to ammonia (NH3).

  8. Chemical cycling - Wikipedia

    en.wikipedia.org/wiki/Chemical_cycling

    Chemical cycling describes systems of repeated circulation of chemicals between other compounds, states and materials, and back to their original state, that occurs in space, and on many objects in space including the Earth. Active chemical cycling is known to occur in stars, many planets and natural satellites.

  9. Ostwald process - Wikipedia

    en.wikipedia.org/wiki/Ostwald_process

    The Ostwald process begins with burning ammonia.Ammonia burns in oxygen at temperature about 900 °C (1,650 °F) and pressure up to 8 standard atmospheres (810 kPa) [4] in the presence of a catalyst such as platinum gauze, alloyed with 10% rhodium to increase its strength and nitric oxide yield, platinum metal on fused silica wool, copper or nickel to form nitric oxide (nitrogen(II) oxide) and ...