# Tag Info

## Hot answers tagged electrochemistry

7

The figures in the OP's post are nicely drawn, as expected in a modern textbook, but figure 3.2(c) has the external battery reversed, which is incorrect. Here is how it works, without the needless complication of the potentiometer. First, start with a standard Daniell cell with standard assumptions, i.e., negligible internal resistance, unimolar ...

6

Your teacher is correct. I will take the example that you gave in the question. You wish to analyze the reaction: $$3\ce{MnO4^{2-}}\to 2\ce{MnO4^{-}}+\ce{MnO2}...(1)$$ This reaction can be split into two parts, the oxidation half reaction, which forms the anode: $$\ce{MnO4^{2-}}\to \ce{MnO4^{-}}+\ce{e-}...(2)$$ And the reduction half-cell, which forms ...

5

If you want energy as heat, the best way to generate energy is combustion. If you want energy as electricity, the best way is a fuel cell (which also produce some heat). If you want mechanical work, using hydrogen like gas or oil in a usual combustion engine, the yield would be a maximum of $30$%. The best yield would be to produce electricity in a fuel cell,...

3

What is absorbance power? Sadly there is nothing called absorbance power. The question setter might have made an mistake by writing absorbance power when they meant absorbance. Absorbance is the ability of an solution to absorb radiations of a particular wavelength. It is defined as the logarithm of the ratio of the initial and final flux(intensity if ...

2

If water is electrolyzed producing $\ce{H2}$ and $\ce{O2}$ gases, a great amount of energy has to be added to this water. The obtained substances are not hotter than the original water. But they possess a much higher potential energy. Their internal energy (and enthalpy, and free enthalpy) is much higher than the same atoms in water. This internal energy may ...

1

In concentrated solutions, some ions are making groups of positive and negative ions which are not able to conduct the current, as if they would make a neutral assembly, as if there was a covalence between them.

1

According to IUPAC pH=-log10(a_H)=-log10(c_H/c^ref gamma_H) where gamma_H is the activity coefficient of H. However, only mean activity coefficients are measurable and therefore gamma_H is the mean activity coefficient. The Donnan potential cannot be part of the mean activity coefficient since it cancels in the computation. The electrochemical potentials of ...

1

Although the exact proof needs complicated, empirically-derived equations, the essential idea is simple. Cobalt(III) is a highly charged cation of a moderately electronegative(1.8) atom, so it wants electrons badly. When bare-naked cobalt(III) is near water, it gets so mad at the highly electronegative, "greedy" oxygen atoms of water's not sharing ...

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