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10

A chemical equilibrium concerns chemical reactions. There should be at least a forward- and backward reaction between two species but more complex systems (polygons, circles, …) with multiple individual reactions may occur. The important observation is that there is no macroscopic change to the chemical constituents of the system, i.e. the concentrations of ...


11

Chemical equilibrium is a type of dynamic equilibrium, but not every dynamic equilibrium is a chemical equilibrium. In a chemical equilibrium there is no change on the macroscopic scale. That means that if you look at the system it seems like nothing is happening, but at molecular scale there are reactions going on and the rate of forward reaction = rate of ...


-2

The answer is No ! Solid have no vapor pressures. And if they still have, this pressure is a constant at the equilibrium conditions. So it does not change between the beginning and the end of the reaction. So it is included in the equilibrium constant.


0

This happens because the equilibrium constant $K_p$ is independent of the pressure, although it does depend on temperature, which we will assume to be constant. The equilibrium constant can be written as $$\displaystyle K_p =\frac{p_A^2}{p_Np_H^3}$$ where for simplicity I have abbreviated the chemical names. The partial pressure $p$ can be written in ...


1

You should consider the Nernst equation $$ \Delta G = \Delta G^{\ominus} + RT\ln Q=- RT\ln Keq + RT\ln Q $$ At equilibrium deltaG is zero and Q the reaction coefficient is Keq also note $$ \Delta G = -nFE $$ so E is zero at equilibrium. Outside equilibrium Q will move towards K decreasing E.


0

An electrochemical cell is producing electricity. So it is out of equilibrium. Reagents which are included in the cell are slowly consumed. The chemical composition of the cell changes, and will slowly tend towards equilibrium. When the reactions are finished, the cell will not produce any electricity later on. The equilibrium is obtained, and the cell is "...


0

As Zhe explains in the comments, the answer is D. Even though small changes in pressure are not expected to significantly affect the chemical potential of a solid, it is a function of pressure: $$\mu(s) = \mu^\circ(s) + \int_{p^\circ}^{p}V_mdp\tag{constant T}$$ This means that a small change in the chemical potential of the solid also contributes to the ...


0

To derive the Gibbs' free energy of an ideal solution you would invoke Raoult's law, which says that $$\mu_i(l) = \mu_i^*(l)+RT\ln\left(\frac{p_i}{p*}\right)= \mu_i^*(l)+RT\ln\chi_i$$ Here the asterisk refers to the pure substance. Using the notation in the OP, the total number of moles of reagent and product in solution is $$n_{tot}=2(1-\xi)+\xi+n_{solv}=...


3

The second definition probably refers to the intensive properties of the phases, not the extent of the phases, being invariant, making the two definitions you present equal. The confusion within the first question you link to has to do with the definition of "boiling" and its application to open systems. Phase transitions of the sort being discussed here ...


6

I think what you are asking is this: Equilibria for chemical reactions typically* (see note at end) require specific ratios of products to reactants (as expressed by the equilibrium constant). By contrast, equilibria for phase transitions don't require specific ratios of products to reactants. [For instance, at the phase transition between ice and water, ...


3

[OP] Why are melting and boiling considered equilibrium processes [...] They should not be considered equilibrium processes. If melting is defined as the process where there is a net change from solid to liquid phase, this is not an equilibrium. If boiling is defined as the process where liquid turns into vapor (rolling boil with bubbles forming below the ...


3

Two different phases of a substance in contact with each other in a closed system at some uniform temperature and pressure (thermal and mechanical equilibrium) will be in equilibrium if the chemical potential of the substance is the same in both phases. It turns out that at its boiling point, a liquid has the same chemical potential as its vapor at that ...


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