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  2. Half-reaction - Wikipedia

    en.wikipedia.org/wiki/Half-reaction

    A half reaction is obtained by considering the change in oxidation states of individual substances involved in the redox reaction. Often, the concept of half reactions is used to describe what occurs in an electrochemical cell, such as a Galvanic cell battery. Half reactions can be written to describe both the metal undergoing oxidation (known ...

  3. Tafel equation - Wikipedia

    en.wikipedia.org/wiki/Tafel_equation

    In other words, it assumes that the electrode mass transfer rate is much greater than the reaction rate, and that the reaction is dominated by the slower chemical reaction rate ". [7] [circular reference] Also, at a given electrode the Tafel equation assumes that the reverse half reaction rate is negligible compared to the forward reaction rate.

  4. Table of standard reduction potentials for half-reactions ...

    en.wikipedia.org/wiki/Table_of_standard...

    The values below are standard apparent reduction potentials (E°') for electro-biochemical half-reactions measured at 25 °C, 1 atmosphere and a pH of 7 in aqueous solution. [ 1 ] [ 2 ] The actual physiological potential depends on the ratio of the reduced ( Red ) and oxidized ( Ox ) forms according to the Nernst equation and the thermal voltage .

  5. Nernst equation - Wikipedia

    en.wikipedia.org/wiki/Nernst_equation

    In electrochemistry, the Nernst equation is a chemical thermodynamical relationship that permits the calculation of the reduction potential of a reaction (half-cell or full cell reaction) from the standard electrode potential, absolute temperature, the number of electrons involved in the redox reaction, and activities (often approximated by concentrations) of the chemical species undergoing ...

  6. Half-life - Wikipedia

    en.wikipedia.org/wiki/Half-life

    In a chemical reaction, the half-life of a species is the time it takes for the concentration of that substance to fall to half of its initial value. In a first-order reaction the half-life of the reactant is ln(2)/λ, where λ (also denoted as k) is the reaction rate constant.

  7. Heterogeneous water oxidation - Wikipedia

    en.wikipedia.org/wiki/Heterogeneous_Water_Oxidation

    Of the two half reactions, the oxidation step is the most demanding because it requires the coupling of 4 electron and proton transfers and the formation of an oxygen-oxygen bond. This process occurs naturally in plants photosystem II to provide protons and electrons for the photosynthesis process and release oxygen to the atmosphere, [ 1 ] as ...

  8. Oxygen reduction reaction - Wikipedia

    en.wikipedia.org/wiki/Oxygen_reduction_reaction

    Rather than combustion, organisms rely on elaborate sequences of electron-transfer reactions, often coupled to proton transfer. The direct reaction of O 2 with fuel is precluded by the oxygen reduction reaction, which produces water and adenosine triphosphate. Cytochrome c oxidase affects the oxygen reduction reaction by binding O 2 in a heme ...

  9. Aluminium–air battery - Wikipedia

    en.wikipedia.org/wiki/Aluminium–air_battery

    The anode oxidation half-reaction is Al + 3OH − → Al(OH) 3 + 3e − +2.31 V. The cathode reduction half-reaction is O 2 + 2H 2 O + 4e − → 4OH − +0.40 V. The total reaction is 4Al + 3O 2 + 6H 2 O → 4Al(OH) 3 +2.71 V. About 1.2 volts potential difference is created by these reactions and is achievable in practice when potassium ...