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A structured approach to this is to use at least five mixtures of the solvents and saturate with caffeine, stirring for at least four hours. The five mixtures are not picked arbitrarily but can be set at idealised levels. If you use 100% ethanol and water as the extremes, then you want 50:50 and two inbetween on either side. These can them be combined ...


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Assume surface molecules are restrained by a QM harmonic potential, with energy levels described as $$E_n = \hbar \omega(n + \frac12)$$ where $$\omega=\sqrt{\frac{k}{\mu}}$$ is the frequency of the harmonic oscillator and $$\mu=\frac{m_1m_2}{m_1 + m_2}$$ is its reduced mass. The actual shape of the potential is determined by $k$, the force constant, ie ...


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Rather than starting out with 100 g of unknown, I would start out with 1 mol of unknown, i.e. 283 g. That way, you can directly calculate how many moles of each element are in one mole of compound: $$ n = 67.3 \% \cdot \frac{\pu{283 g}}{\pu{12 g mol-1}} = \pu{15.86 mol}$$ Or to get the stoichiometric coefficient $\nu_C$ directly, take the percentage and ...


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Proper definitions of chemical equilibrium will not involve reaction rates whatsoever. Thermodynamics does not care about time. Chemical potential is the work required to form a molecule in solution, irregardless of the time it takes. Statistical Mechanics says chemical potential is the work required to move a molecule from infinitely far away (ideal gas ...


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I expect it may be due to the basic definition of chemical equilibrium simply being inadequate This is the answer (sort of). In essence, when you are below the solubility limit, the chemical potential of the solid lies above that of the solubilized salt, and there is no equilibrium with the solid (because no solid can form). This is illustrated in the ...


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You have to look at two things in terms of equillibrium. The pot with the solution, once all AgCl is dissolved and you have stirred it a bit more, is in equillibrium. Obviously. There is no chemical potential gradient, and you have only one phase. By itself, nothing will ever happen again in it. The reaction (dissolution of AgCl in water) isn`t: If you add ...


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There are two ways to add two miscible solvents to each other. One is the bartender skill, whereby you attempt to create two different layers of solvents and then try to keep the flask motionless to prevent mixing. The other way is to mix them all along, whether by shaking, careless pouring, or a stirring bar. I will concentrate on the second as that is, in ...


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Of course there are such solutions. Take, as an example, Sigma-Alrich's offer of methanolic solution of HCl (3 mol/L, e.g. here), or the dry ones in diethyl ether (e.g., 2 mol/L here), in cyclopentyl methyl ether (e.g., here), or in 1,4-dioxane (e.g. 4 mol/L, here).


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In addition to all the qualities @Karl stated (harmless, edible, overspray decomposes, etc.), such a coating would also need to stretch as the produce grows. Such a protective covering might even obviate the need for pesticides, if it were to be created. That said, there are edible wax and protein coatings to preserve produce after it's picked. ...


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1) For what condition do the equations [6] and [7] apply? I think that [7] is for strong electrolytes at low concentration though im not sure. So what about at high concentrations of strong electrolytes? What about weak electrolytes? 2) When would you use equation [6], when would you use equation [7]? Are they equivalent? Equation [6] defines the molar ...


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