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2 is no longer zero as with the standard hydrogen electrode (SHE) at 1 M H + (pH = 0) in classical electrochemistry, but that = versus the standard hydrogen electrode (SHE). [2] The same also applies for the reduction potential of oxygen: O 2 + 4 H + + 4 e − ⇌ 2 H 2 O
A redox indicator (also called an oxidation-reduction indicator) is an indicator which undergoes a definite color change at a specific electrode potential. The requirement for fast and reversible color change means that the oxidation-reduction equilibrium for an indicator redox system needs to be established very quickly. Therefore, only a few ...
The larger the value of the standard reduction potential, the easier it is for the element to be reduced (gain electrons); in other words, they are better oxidizing agents. For example, F 2 has a standard reduction potential of +2.87 V and Li + has −3.05 V: F 2 (g) + 2 e − ⇌ 2 F − = +2.87 V Li + + e − ⇌ Li (s) = −3.05 V
In aqueous solutions, redox potential is a measure of the tendency of the solution to either gain or lose electrons in a reaction. A solution with a higher (more positive) reduction potential than some other molecule will have a tendency to gain electrons from this molecule (i.e. to be reduced by oxidizing this other molecule) and a solution with a lower (more negative) reduction potential ...
Calculates pH of solutions after addition of chemicals (acids, bases, salts) Calculates the calcite-carbonate system (closed/open CO 2 system, Langelier Saturation Index) Calculates mineral dissolution, precipitation, and saturation indices; Calculates mixing of two waters; Calculates reduction-oxidation reactions; Plots titration curves
Overall 2H 2 O → 2H 2 + O 2 E°cell = +1.23 V; ΔG = 475 kJ/mol . Water splitting can be done at higher pH values as well however the standard potentials will vary according to the Nernst equation and therefore shift by -59 mV for each pH unit increase. However, the total cell potential (difference between oxidation and reduction half cell ...
For example, from Fe 2+ + 2 e − ⇌ Fe(s) (–0.44 V), the energy to form one neutral atom of Fe(s) from one Fe 2+ ion and two electrons is 2 × 0.44 eV = 0.88 eV, or 84 907 J/(mol e −). That value is also the standard formation energy (∆ G f °) for an Fe 2+ ion, since e − and Fe( s ) both have zero formation energy.
Because H + ions participate into redox reactions to balance acid–base reactions related to the O 2− anions released in solution during reduction, or at the contrary consumed by oxidation reactions, according to Le Chatelier's principle, the oxidizing power of oxidizing agents is exacerbated under acidic conditions (2 H + + O 2− ⇌ H 2 O ...