Search results
Results from the WOW.Com Content Network
Half-reaction. In chemistry, a half reaction (or half-cell reaction) is either the oxidation or reduction reaction component of a redox 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 ...
The oxygen reduction reaction is an essential reaction for aerobic organisms. Such organisms are powered by the heat of combustion of fuel (food) by O 2. 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 ...
Redox (/ ˈrɛdɒks / RED-oks, / ˈriːdɒks / REE-doks, reduction–oxidation[2] or oxidation–reduction[3]: 150 ) is a type of chemical reaction in which the oxidation states of the reactants change. [4] Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the ...
In the above equation, the Iron (Fe) has an oxidation number of 0 before and 3+ after the reaction. For oxygen (O) the oxidation number began as 0 and decreased to 2−. These changes can be viewed as two "half-reactions" that occur concurrently: Oxidation half reaction: Fe 0 → Fe 3+ + 3e −; Reduction half reaction: O 2 + 4e − → 2 O 2−
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 ...
The hydrogen electrode is based on the redox half cell corresponding to the reduction of two hydrated protons, 2H+(aq), into one gaseous hydrogen molecule, H2 (g). General equation for a reduction reaction: The reaction quotient (Qr) of the half-reaction is the ratio between the chemical activities (a) of the reduced form (the reductant, ared ...
Heterogeneous water oxidation. Water oxidation is one of the half reactions of water splitting: 2H 2 O → O 2 + 4H + + 4e − Oxidation (generation of dioxygen) 4H + + 4e − → 2H 2 Reduction (generation of dihydrogen) 2H 2 O → 2H 2 + O 2 Total Reaction. Of the two half reactions, the oxidation step is the most demanding because it ...
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 .