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The data below tabulates standard electrode potentials (E°), in volts relative to the standard hydrogen electrode (SHE), at: Temperature 298.15 K (25.00 °C; 77.00 °F); Effective concentration (activity) 1 mol/L for each aqueous or amalgamated (mercury-alloyed) species; Unit activity for each solvent and pure solid or liquid species; and
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
The standard potential for the reaction is then +0.34 V − (−0.76 V) = +1.10 V . The polarity of the cell is determined as follows. Zinc metal is more strongly reducing than copper metal because the standard (reduction) potential for zinc is more negative than that of copper.
Zinc chemistry resembles that of the late first-row transition metals, nickel and copper, [53] as well as certain main group elements. Almost all zinc compounds have the element in the +2 oxidation state. [54] When Zn 2+ compounds form, the outer shell s electrons are lost, yielding a bare zinc ion with the electronic configuration [Ar]3d 10. [55]
A Latimer diagram of a chemical element is a summary of the standard electrode potential data of that element. This type of diagram is named after Wendell Mitchell Latimer (1893–1955), an American chemist.
To avoid possible ambiguities, the electrode potential thus defined can also be referred to as Gibbs–Stockholm electrode potential. In both conventions, the standard hydrogen electrode is defined to have a potential of 0 V. Both conventions also agree on the sign of E for a half-cell reaction when it is written as a reduction.
In the Daniell cell, copper and zinc electrodes are immersed in a solution of copper(II) sulfate and zinc sulfate, respectively. The two-half-cell form for classroom demonstrations. At the anode (negative electrode), zinc is oxidized as per the following half reaction: Zn (s) → Zn 2+ (aq) + 2e −. . (Standard electrode reduction potential ...
Where is the standard reduction potential of the half-reaction expressed versus the standard reduction potential of hydrogen. For standard conditions in electrochemistry (T = 25 °C, P = 1 atm and all concentrations being fixed at 1 mol/L, or 1 M) the standard reduction potential of hydrogen is fixed at zero by convention as it serves of reference.