New answers tagged redox
2
It's hard to pinpoint what the problem here is since I don't have the mentioned book to compare an answer with.
The simplest way is write down half-reactions for reduction (red) and oxidation (ox) processes once you've assigned oxidation numbers (denoted above the symbols of the elements which are participating in a redox reaction), then balance the number ...
4
The reaction is with an advantage written in the simplified ion form:
$$\ce{5 Fe^2+ + MnO4- + 8 H+ -> 5 Fe^3+ + Mn^2+ + 4 H2O}$$
Total oxidation numbers $+17=+17$
The oxidation number is formally the net charge an atom within a molecule would have held, if we had broken all bonds and bond electrons had sticked to atoms according the atom ...
2
The little problem with the standard addition in potentiometry is, that the response to the addition is not linear, but logarithmic.
If we consider the simplified Nernst equation in context of parameters $A, B$,
and if we consider $c, c_\mathrm{0}$ as unknown concentration and concentration increment, respectively,
we can follow this derivation:
$$\...
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Run everything one more cycle and you are totally safe. Copper is highly soluble in water, so it will entirely dissolve and go away, not contaminating your plates.
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Graphite is elemental carbon, and carbon is unstable in the presence of oxygen because they react to form carbon dioxide. The rate of this reaction: $\ce{C + O2 = CO2}$ is very slow and has a high activation energy, so a piece of graphite can sit in oxygen at room temperature for millions of years without anything happening to it. Once temperature increases, ...
1
Think of oxidation in a classical sense for a minute or so. Oxidation is addition of oxygen to a molecule or it can also mean removal of hydrogen. If you carefully look at the structure of ascorbic acid, you will see that the two -OH groups are now converted into carbonyl groups. Those two hydrogens can be lost as a proton, H+.
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