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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Adjusting the Equilibrium of a Solution to change pH by kinetic impact [closed]

I am a physics student with introductory chemistry experience. Im being tasked with using collisions to show the differences in elasticity of collisions (basically how much kinetic energy is lost). I ...
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Equilibrium constant expression after multiplying stoichiometric coefficients with a constant factor [duplicate]

We know that the equilibrium constant of a balanced chemical reaction $$aA+bB \rightarrow cC+dD$$ is defined as $K_\mathrm{c}=\frac{[C]^c[D]^d}{[A]^a[B]^b}$. But if we multiply both the left hand side ...
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Why does CaSO4 break up when adding HCl but not BaSO4?

I observed in a solution with CaSO4 that the white precipitate dissolved when I added concentrated hydro chloric acid (37%). I assume CaSO4 had a divorce and Ca decided to hook up with two Cl- ions, ...
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chemical equilibrium and activity

Here is a graph of equilibrium coeff in various salt concentrations in water. Lets take the example $\ce{BaSO4}$. Now as we are increasing the salt concentration in water, the following reaction is ...
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Carbohydrates with a free aldehyde or keto group have the ability to reduce metallic ions [closed]

In this test what metallic ion is reduced?
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Is NH4HCO3 acidic or basic acid salt? [closed]

i am confused on NH4HCO3 being acidic or basic acid salt , even after searching there were not answers for this compound
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Does the acidity constant depend on the solvent?

Today I came across $pK_a$ values that depend on the solvent. For the hypothetical reaction $HA \rightarrow H^+ + A^-$, I had in mind that the acidity constant is defined simply as $K_a = \frac{\{H^+\}...
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What is the difference between a single displacement reaction and a two competing reaction system?

For example, consider the single-displacement reaction $$\ce{AB + C <=> BC + A}$$ My question is then if writing this reaction as the system \begin{gather} \ce{AB <=> A + B} \\ \ce{B + C &...
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Le Chatelier's Principle - Increasing concentration of coloured ion

Take the following equilibrium: $$\ce{[CoCl4]^2- + 6H2O <=> [Co(H2O)6]^2+ + 4 Cl^-}$$ Where $\ce{CoCl4^2-}$ is blue and $\ce{[Co(H2O)6]^2+}$ is pink. My understanding is that Le Chatelier's ...
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Total entropy change for reversible reactions and its relationship to equilibrium constant

I'm in year 12 of school doing A2 chemistry learning about entropy and its relationship to reversible equilibria. I learned about the following three ideas from my course book (verbatim), for a ...
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Schlögl model - Stationary States far from Equilibrium

The Schlögl model can be represented as follows: $$ A + 2X \underset{k_2}{\stackrel{k_1}{\rightleftharpoons}} 3X \, , \\ X \underset{k_4}{\stackrel{k_3}{\rightleftharpoons}} B \, . $$ The chemical ...
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What is the significance of charge balancing when analysing system speciation (carbonate system given as an example)?

Following on from my previous question and accepted answer, How do I quantify the carbonate system and its pH speciation?, I also calculated a charge balance ($CB$) on the system where $z$ is the ...
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How does pressure affect the color of reaction medium with equimolar amounts or reactants and products at equilibrium?

Chlorine gas is pale yellow-green, and both hydrogen and hydrogen chloride are colorless gases. According to the Le Chatelier's principle, the change in pressure will not affect the following ...
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Help understanding Isothermal titration calorimetry ITC

Trying to understand Isothermal titration calorimetry: ITC , from a public online forum (Off-topic question related to ITC binding studies) I got this question: We performed an ITC binding study (...
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Is the entropy change positive or negative in this reaction?

Suppose I have a reversible reaction \begin{align} \ce{A(g) + B(g) <=> C(g)}\\ \end{align} with equilibrium constant K. Its ΔΗ is positive throughout. Now, suppose I start with 1 mole ...
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In a 20wt% ammonia solution, what are the species in solution?

I have bought a 20wt% ammonia solution. It is described as having a specific gravity of 0.92. I worked out its Molarity earlier today, and I think it was approximately 10M My question can I assume ...
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Titration of a weak acid with a strong base

I recently learned that when titrating a strong base like NaOH into a weak acid, like Acetic Acid, a buffer region/zone develops and can be illustrated as follows: CH₃COOH + OH⁻→ CH₃COO⁻ + H₂O I've ...
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How do I quantify the carbonate system and its pH speciation?

I did Environmental Water Chemistry as part of my undergraduate course where we quantified pH-speciation for the full carbonate system and I got it right according to my tutor. My speciation profile ...
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Degree of dissociation and conductance

My book says ratio of molar conductance at a given concentration of solute and molar concentration at infinite dilution is equal to degree of dissociation for weak electrolytes. I understand it ...
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Rate law for thermolysis at temperatures well above the decomposition temperature

If the temperature is higher than the decomposition temperature, are thermal decomposition reactions reversible? For example, which of the following schemes would be more appropriate for temperatures ...
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Why don't we take activities in the rate law?

I am slightly confused by the fact that concentrations and not activities are taken in the rate law which is different to equilibrium and seems to lead to a discrepancy. For example, for the reaction $...
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Why does equilibrium of ice and water only exist at 273K at normal pressure?

I am a high school student and I am a little confused in the concept of spontaneity of a reaction and how equilibrium works for a reaction, I got some confusions: Let's take example of freezing of ...
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Zwitterionic Form in Amino Acid

In my laboratory workbook, it has been mentioned that the zwitterionic form of the amino acid is the dominant form of the amino acid at pI and no movement of the molecules takes place under an ...
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Are there any well documented reactions with "persistent" intermediates

I'm a biology and/or math person, not a chemistry person. I have only taken the standard sequence of undergraduate courses up to organic chemistry, and that was some time ago, so please excuse (and ...
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Notation for acid-base reactions of differing strengths - equilibrium?

I'm having trouble finding anything meaningful in textbooks or searches. My question is what is the correct notation for writing acid-base reactions when their strengths are varying? I know that ...
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Estimating the heat that must be removed or add to keep the temperature of a mixture constant- Thermodynamics

I'm trying to solve this exercise from the book "The Thermodynamics of Phase and Reaction Equilibria" from Ismail Tosun. What I've done so far: -I've calculated Gex/RT (Gex=Excess Gibbs ...
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Why does the equation for chemical potential apply to liquids and aqueous solutes?

The equation for chemical potential of a gas can be derived as such: At constant temperature, $$\mathrm dG = V\,\mathrm dP \label{eqn:1}\tag{1}$$ Substituting with the ideal gas law $PV = nRT$, $$\...
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Mathematical models of Vaporization-Condensation dynamics

I am a mathematician now studying an introductory chemistry course. Consider a liquid in a closed container, at (say) room temperature. Then some of the liquid will vaporize. Then some of the ...
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Why is this equation true for a salt in acid?

I previously asked a question about a calculation (below) Calculate the molar solubility of $\ce{SrF2}$ in a solution buffered at pH = 2.00. ($K_{a}$ for HF is $7.2 \times 10^{-4}$). The $K_{sp}$ of $...
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Reason of using reversible signs [duplicate]

We see that for weak electrolytes we use $$\ce{<=>}$$ e.g reversible symbol and for strong ones we use $$\ce{->}$$ e.g irreversible symbol. For example,we write $$\ce{CH3COOH <=> CH3COO^...
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Is there an agreement for a specific temperature referred to in the context of standard Gibbs energy? [duplicate]

I found an exercise in Physical Chemistry by Atkins et al, 8th edition, page 235 that I found confusing. The question is as follows. "7.2(b) Molecular bromine is 24 per cent dissociated at 1600 K ...
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Effect of Pressure on Equilibrium

This might be a little bit of a basic question, but I've been trying to get my head around pressure and Le Chatelier's principle and I can't quite understand it. Currently, my understanding of Le ...
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Why don't we multiply Ksp and Kf?

My understanding is that for a process with two reactions having the equilibrium constants K1 and K2, K for the full process is K = K1 x K2. However, in this problem in my book where complexation ...
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Electrode potential for saturated silver carbonate solution

An electrochemical cell is set up to measure the electrode potential $E(\ce{Ag^+}/\ce{Ag})$ using the saturated $\ce{Ag2CO3(aq)}$ solution $(K_\mathrm{sp}(\ce{Ag2CO3(aq)},\pu{25 °C}) = \pu{6.3E-12})$ ...
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Finding relation between Gibb's free energy and equilibrium constant for a homogeneous gaseous phase reaction

I was trying to find relation between Gibb's free energy change and equilibrium constant for the following homogeneous gaseous phase reaction at constant temperature $$\ce{aA +bB }\rightleftharpoons \...
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H+ concentration decreasing over time reasoning in weak acid strong base titration

We know that, when $\ce{CH3COOH}$ is just present in water, it is in equilibirum with water and having some $\ce{H+}$ dissociated to give some $\mathrm{pH}$ to it. Now when we start adding $\ce{NaOH}$ ...
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Misconception regarding mean ionic activity coefficient and applying it to equilibrium constants

I probably have some simple misconception about the mean ionic activity. The mean ionic activity coefficient is defined as $$ \gamma_{\pm} = \sqrt[^{p+q}]{\gamma^p_+\gamma^q_-} \tag{1} $$ I'm just not ...
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Importance of equilibrium constant [closed]

Here i am going to let out a doubt of mine which has been bothering me since high school about equilibrium constant. Let's say we have a reaction. $A+B\rightarrow C+D$. When we say reversible ...
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Vapor-Liquid Equilibrium and partial pressure of ammonia

I tried searching the forums for a similar question but I do not think it was entirely answered: Suppose I have a closed system in a container with solvent and a certain concentration of gas, say ...
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How to find ion concentrations at various points in a solution that will precipitate multiple insoluble salts?

The solubility product constant of lead (II) iodide is $1.2 \times 10^{-5}$ at 273 K. The solubility product constant for lead (II) carbonate is $1.5 \times 10^{-13}$ at the same temperature. 50 ...
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Interpreting Ternary Phase Diagram Stoichiometry

I am trying to locate the lowest-melting mixture in a system of three nitrate salts: sodium, potassium, and calcium nitrate. I have the relevant ternary phase diagram, but I am unsure exactly about ...
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Acidity and Basicity of titrate and titrant in Acid-Base titration

I want to know that do we always use monoprotic acid and bases in the Acid-Base Titration. And, if the answer is No. Then, I am confused in the definition of Equivalence Point, because I had seen on ...
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Combining two reactions in equilibrium with same reactants but different products: What would be the new K?

If I have the reactions : A(g) ⇌ B(g)   K1 A(g) ⇌ C(g)   K2 Am I able to add the equations like done in Hess's law despite nothing canceling out? And if I can do so, is the new equilibrium ...
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Relation between Solubility Product and Equilibrium Constant

I had read about Solubility, and I found that Solubility is not Molarity (because previously I believe that both are same thing). But, they have a big difference (source : https://en.wikipedia.org/...
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Why is molar density of solids and liquids taken as 1? [duplicate]

In the expression for equilibrium constant, the molar density values of solids and liquids are taken as 1. Is the active mass taken as the molar density of reaction divided by molar density at ...
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Standard Gibbs free energy when all the reactants and products are at standard condition

I have read in my textbook that for a reaction $\Delta G=\Delta G^o-RT\ln Q $, where $\Delta G^o$ is the Gibbs free energy change when the initial concentration of products and reactants are unity. ...
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Relevance of equilibrium constant Kp for reaction when reactant is solely a solid and is absent

Consider a reaction where a solid dissociates to give gases. There must a equilibrium between them, define the equilibrium constant in terms of pressure as $K_p$. Suppose I take the gases alone in a ...
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Can water synthesis and decomposition be in a dynamic equilibrium?

When heated at extreme temperatures, water can spontaneously decompose. According to Wikipedia (https://en.wikipedia.org/wiki/Water_splitting): In thermolysis, water molecules split into their atomic ...
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Between compounds having same functional groups, why does the one with greater -I effect have higher acidic strength

Consider the two compounds $\ce{FCH2COOH}$ and $\ce{ClCH2COOH}$. Since fluorine is more electronegative than $\ce{Cl}$ it will show a greater –I effect. It will pull the the electrons closer towards ...
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How does pH affect an extraction problem

I am not sure how to understand when pH will affect a given problem regarding extraction. For example, in a problem given that K$_D$ of the reaction is $1.86$ I am asked to calculate: (a) How much ...
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