# Questions tagged [equilibrium]

The state in which both reactants and products are present at concentrations which have no further tendency to change with time.

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### Finding ionic radii from solubility data and density

$\pu{5.35 g}$ of a salt $\ce{ACl}$ is dissolved in $\pu{250 ml}$ of solution. The $\mathrm{pH}$ of the resultant solution was found to be $4.85.$ Find the ionic radius of $\ce{A+}$ and $\ce{Cl-}$ if ...
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### Genuine confusion about the equilibrium constant [closed]

I gather that the equilibrium constant K = 1 implies that, at equilibrium, neither the forward nor the backward reactions are thermodynamically favoured. But if pressure of the system increases and ...
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### Mathematical justification for Le Chatelier's principle

At equilibrium \begin{align} K &= \exp\left(\cfrac{TΔS^\circ - ΔH^\circ}{RT}\right)\\ ⇒ \frac{\mathrm d \ln K}{\mathrm dT} &= \frac{ΔH^\circ}{RT^2} \end{align} If enthalpy change is ...
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### When is the concentration in which you put into the equilibrium constant equal to 1 for solids and liquids?

There are many websites which states that pure liquids and solids have a concentration equal to one, but for some equations they are not! How do you explain the difference for this equation? For the ...
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### How to confirm experimentally that a hemi-acetal compound has formed?

I have read that under mildly acidic or alkaline conditions alcohols can attack aldehydes/ketones to produce hemi-acetals. But the reaction is reversible, so the reactants and the hemia-cetal are in ...
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### How do I find pH of a mixture of weak acids? [duplicate]

Suppose that we are given two weak bases $\ce{HA_1}$ and $\ce{HA_2}$. We are also given the $K_\ce{HA_1}$ and $K_\ce{HA_2}$. How can we calculate the $\mathrm{pH}$ of the mixture?
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### Defining the position of equilibrium

I've read quite a few other answers on this site such as this one, but can't quite seem to understand fully yet. Say we have a container with gases reacting such that the number of moles on both ...
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### Calculating thermodynamic quantities for hydrogenation of iron nitride

HW#6.3 If the reaction $$\ce{Fe2N(s) + 3/2 H2(g) <=> 2 Fe(s) + NH3(g)}$$ comes to an equilibrium at a total pressure of $\pu{1 bar},$ analysis of the gas shows that at $\pu{700 K}$ ...
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### Chaos in chemical reactions

I recently read about Chaos Theory and was wondering if a chemical reaction results in or shows characteristics of chaos (I found a few examples of such reactions here) Chaos theory concerns ...
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### Calculation of equilibrium constant in a gaseous system A ⇌ B + C

I am supposed to determine whether the following two statements are true or false: For the reaction $\ce{A (g) <=> B (g) + C(g)}$, $K_p = \pu{1 atm}$. If we start with equal moles of all ...
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### Liquid solutions and vapour pressure

"The vapour pressure of water at 80° C is 355 torr. A 100 mL vessel contained water-saturated oxygen at 80° C, the total gas pressure being 760 torr. The contents of the vessel were pumped into a 50 ...
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### Why are the equilibrium exponents stoichiometric when the rate law's are not? [duplicate]

I'm learning about rate law and equilibrium, and the textbook really hammers in that the exponents for the rate law must be determined experimentally - you can't just use the coefficients from the ...
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### What is meant by pure solids or pure liquids? [duplicate]

In by book, under the topic Heterogeneous Equilibrium it is given For pure solid and pure liquid, active mass is taken to be unity, i.e., 1 as they remain constant throughout the reaction. Could ...
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### Ce₂(SO₄)₃ solubility in water [duplicate]

I have mostly come across examples of solids whose solubility increases in liquids with an increase in temperature. However, there seem to be exceptions to generalized rule this such as the solubility ...
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### Why is the equilibrium constant unitless?

I read that the equilibrium constant is unitless because the molar activities of each of the species are used in the equilibrium expression, not the actual concentrations themselves. I understand that....
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### Is “mass-action ratio” identical to “reaction quotient?”

Mass-action ratio Reaction quotient According to their definitions expressed in the above Wikipedia articles, these two concepts seem to be totally identical. Is that true? If not, what is the ...
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### How can I calculate the equilibrium between several reactions?

If I mix xNaOH + yCdCl2 + zZnCl2 in an aqueous medium, how can I calculate the final equilibrium quantities of the resulting salts (which I suppose may be the following): Q1 NaOH Q2 CdCl2 Q3 ZnCl2 Q4 ...
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### Equivalents Triethylamine in Swern-oxidation

Hey folks, so I've been wondering why the use of 5 equivalents of Et3N in this case of a Swern-oxidation is necessary. I have done this reaction succesfully quite a few times now, but all the ...
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### Are there any exceptions to Le Chatelier’s principle? [duplicate]

Peter Atkins says In introductory chemistry, we meet the empirical rule of thumb known as Le Chatelier’s principle: When a system at equilibrium is subjected to a disturbance, the ...
54 views