Questions tagged [equilibrium]

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

Filter by
Sorted by
Tagged with
2
votes
2answers
30 views

What is the difference between chemical equilibrium and dynamic equilibrium?

Is chemical equilibrium and dynamic equilibrium the same thing? Both point to the reversible reactions and no net changes in the concentrations of product and reactant. Dynamic equilibrium from ...
-1
votes
0answers
15 views

Original reference of multiplicative coupled equilibria [closed]

Can I know what is the peer-reviewed reference behind the multiplicative nature of two equilibrium constants of two reactions that are additive? Example:
1
vote
0answers
31 views

Thermochemical data for thiocyanatoiron(III) ion

I am currently writing a lab report about the formation constant of $\ce{FeSCN^2+}.$ All I could find online was a formation constant at $\pu{25 °C}$ $(890),$ which was 70% higher than the ...
-1
votes
0answers
23 views

Find the concentration of each substance at equilibrium

I have a question that asks me to find the concentration of each substance when the equilibrium of the reaction is established: We pour $\pu{0.02L}$ of $\ce{Ba(NO3)2}$ ($\pu{0.1 mol/L}$) into $\pu{...
-1
votes
1answer
18 views

Chemical equilibrium [duplicate]

When calculating equilibrium constant with partial pressures if there is a solid involved should we consider it in the total number of moles in mole fraction?
0
votes
1answer
19 views

What exactly causes equilibrium to shift when pressure is decreased? [duplicate]

Take the reaction: $$\ce{N2(g) + 3 H2(g) <=> 2 NH3(g)}$$ If pressure is decreased, equilibrium shifts to the left because it has more moles. I understand the basics of why this is, i.e. due to ...
6
votes
0answers
48 views

Using Le Chatelier's Principle to Change Mechanical Energy to Chemical Energy

I was interested in an application of Le Chatelier's principle, where an increase in pressure could result in a decrease in the moles of gas. In particular, a situation where when the pressure ...
0
votes
2answers
37 views

Equilibrium of an electrochemical cell [closed]

I am quite new to the field. So try to figure out what is meant by the equilibrium state of an electrochemical cell? Is it, where both half cells passing the same number of electrons to either side? ...
1
vote
1answer
42 views

Gibbs energy derivative vs equilibrium for aqueous reaction

I am trying to find the Gibbs-energy equilibrium for the reaction $$\mathrm{A}+\mathrm{B}\rightleftharpoons\mathrm{C}.$$ According to most sources the equilibrium concentrations in an ideal solution ...
4
votes
0answers
25 views

How are σ+ values in Hammett Plots calculated?

First of all, I know a similar question has already been asked & answered about σ values in general, however, I am not 100 % sure this answer is correct for the following situation. So for the σ ...
4
votes
1answer
56 views

How is a phase equilibrium defined for a one-component system?

A question on this site asked whether a one-component system is at equilibrium when melting or boiling, and the disparate answers were somewhat dependent on the definition of phase equilibrium. ...
2
votes
3answers
158 views

melting and boiling …really equilibrium? [closed]

Why are melting and boiling considered equilibrium processes even though the amount (concentration) of both phases keep changing i.e from solid to liquid and so on?
1
vote
0answers
17 views

Azeotropic Distillation - Am I interpreting this VLE diagram correctly?

I've been looking at ways to re-concentrate a formic acid-water binary mixture with the VLE diagram below. Am I correct in saying that to concentrate a solution of say , 40% formic acid by weight I ...
-1
votes
0answers
21 views

Does putting a reversible reaction out of equilibrium affect temperature?

Lets say we have a reversible reaction in equilibrium A + B <--> C. It's exothermic towards the right. Would increasing the concentration of A or B cause a temporary increase in temperature from ...
2
votes
1answer
94 views

Spectroscopic Determination of an Equilibrium Constant [closed]

I got values of $\pu{5.0E-4}$, $\pu{2.5E-4}$, and $183$ for the following problems. However, these seem to be inaccurate and I'm not sure what to do. Here is the procedure: Obtain 6 disposable ...
0
votes
0answers
59 views

Gibbs free energy of phosphorus pentachloride decomposition reaction

The equilibrium constant at $\pu{227 °C}$ for the equation $$\ce{PCl5(g) <=> PCl3(g) + Cl2(g)}$$ is $K_p = \pu{4.50E3 bar}.$ Calculate the value of $Δ_\mathrm{rxn}G^\circ$ at $\pu{227 ...
4
votes
1answer
79 views

Cases when Raoult's law is unsolvable

Setup Consider a closed binary mixture of known total molar composition $n_i$, held at volume $V$ and temperature $T$. The equilibrium phase composition is determined by $\mu_i^{vap} = \mu_i^{liq}$. ...
2
votes
2answers
125 views

Calculating partial pressure of carbon monoxide

$\ce{ZnO}$ is exposed to pure $\ce{CO}$ at $\pu{1300 K}$ and the equilibrium $$\ce{ZnO(s) + CO(g) <=> Zn(g) + CO2(g)}$$ is then established at $\pu{1 atm}$ pressure. The density of the ...
2
votes
2answers
63 views

Can the rate of reaction of a Voltaic/Galvanic cell be determined theoretically?

I am conducting a chemistry practical in which I measure the voltage of a Zn-Cu Voltaic cell over time. Assuming that the surface area of the electrodes are known, concentration of reactants are ...
0
votes
1answer
52 views

Why does an electron lose energy so that it falls back to a lower energy state than just stay at the higher energy state?

Suppose an electron in the 2nd shell gets excited and jumps to the 4th shell. Shouldn't the electron then exist in an unstable equilibrium in the 4th shell, than lose energy and drop down to the 2nd ...
5
votes
1answer
147 views

What is the true meaning of Gibbs energy and chemical potential?

After doing some research and reading I found some problems which I will try to state as clearly as possible. The definition of Gibbs Free Energy says "the greatest amount of mechanical work which ...
3
votes
1answer
168 views

How can batteries reach equilibrium if the reactions are irreversible?

My book says that the batteries we have considered so far (Daniell cells) have a low life span because they reach equilibrium too quickly. In the next paragraph, it states they are also made by ...
0
votes
2answers
47 views

Does salt hydrolysis takes place in buffer solution? [closed]

I am a bit confused whether hydrolysis of salt takes place in buffer solutions because the books which I read doesnt consider them.But I think since weak base or weak acid salt is present hydrolysis ...
-1
votes
1answer
45 views

Equilibrium pressure

Ammonium carbamate dissociates as follows: $$\ce{NH2COONH4(s)<=> 2NH3(g) + CO2(g)}$$ The value of $K_p$ for this reaction is found to be equal to $\pu{2.92 \times 10^-5 atm^3}$. If ...
-4
votes
1answer
36 views

When pH > pKa and when pH < pKa and the effectiveness of buffer solutions

I understand that when $\mathrm{pH}= \mathrm{p}K_\mathrm{a}$, the buffer solution will be at its maximum capacity, and there will be equal concentrations of the acid/conjugate acid and the base/...
0
votes
2answers
59 views

Why does reducing the pressure in an equilibrium reaction favour the side with more moles of gas?

I was trying to explain it in terms of reaction rates and such; more than just 'Le Chatelier's principle states ...', but I can't figure out the underlying reason as to why. I can explain why for ...
4
votes
2answers
121 views

Equilibrium Constant & Rate-Determining Step

My first language is not English, so there might be some parts where it's hard to read. Sorry in advance. I have some questions regarding the derivation of the equilibrium constant and the rate-...
1
vote
0answers
40 views

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 ...
2
votes
3answers
95 views

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 ...
2
votes
1answer
100 views

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 ...
0
votes
0answers
15 views

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 ...
0
votes
0answers
16 views

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 ...
1
vote
0answers
39 views

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?
1
vote
1answer
52 views

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 ...
1
vote
0answers
42 views

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 $\pu{700 K}$ ...
2
votes
2answers
134 views

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 ...
5
votes
1answer
109 views

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 ...
1
vote
1answer
36 views

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 ...
1
vote
0answers
45 views

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 ...
2
votes
0answers
42 views

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 ...
0
votes
0answers
56 views

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 ...
0
votes
1answer
86 views

How can I calculate the equilibrium constant for this reaction?

Silver(II) oxide partially decomposes into solid silver and oxygen gas according to: $$\ce{2 AgO(s) <=> 4 Ag(s) + O2(g)}$$ with enthalpy $H^\circ = \pu{62.0 kJ}$ and entropy $S^\circ = ...
0
votes
2answers
430 views

Understanding the solubility of Ca(HCO3)2

According to wikipedia Ca(HCO3)2 has the following solubility values: 16.1 g/100 mL (0 °C) 16.6 g/100 mL (20 °C) 18.4 g/100 mL (100 °C) So I assume Ca(HCO3)2 would precipitate beyond this level. ...
1
vote
3answers
93 views

$K_c$ vs $K$ in equilibrium reactions

I don’t understand why the following question The decomposition of nitrosyl bromide $(\ce{NOBr})$ proceeds by the following reaction: $$\ce{2 NOBr(g) <=> 2 NO(g) + Br2(g)} \qquad K = 0....
2
votes
1answer
47 views

Reversibility of a reaction

I was doing some questions on equilbrium. I got stuck in this particular question. Identify which of the following reactions are reversible. $$ \begin{align} \ce{Fe + S &-> FeS }\label{...
0
votes
0answers
5 views

Book reference for chemical equilibriums [duplicate]

I need to practice more chemistry equilibrium questions but most of the books contain only theory parts and not enough questions. so can please recommend me a question book.
4
votes
1answer
177 views

Same Activation Energy for Forward and Backward Reactions

While reading about equilibrium, I read that the equilibrium constant, $K_\mathrm{c}$, changes with temperature due to the forward and backward reactions having different activation energies. Is it ...
0
votes
1answer
118 views

Can precipitation reactions attain equilibrium?

While studying about the characteristics of Chemical Equilibrium, I came across a point in my book which read A chemical equilibrium can be established only if none of the products is allowed to ...
0
votes
2answers
79 views

Is the equilibrium constant calculation only applicable to homogeneous reactions?

In my text book, it states the general formula for the equilibrium constant is: Then it states that "The equilibrium constant expressions described here apply to homogeneous reactions." Does this ...
1
vote
0answers
30 views

Calculating Equilibrium Constant from Cell Potential at Nonstandard Temperature

I'm currently working on a problem for a general chemistry class. This is the voltaic cell given in the problem: $$\ce{Sn^4+(aq) + Cu(s) -> Sn^2+(aq) + Cu^2+(aq)}$$ $$E^\circ_{cell} = \pu{-0.21 V}$$...