Questions tagged [equilibrium]
The state in which both reactants and products are present at concentrations which have no further tendency to change with time.
1,673
questions
-4
votes
0
answers
29
views
Finding Ksp from electrochemical data? [closed]
I've been stuck on this question for a week now and can't find a similar problem anywhere. Can someone explain how to solve this?
An electrochemical cell is created based on the Zn(NO3)2 (aq) | Zn (s) ...
0
votes
0
answers
55
views
Products formed on reaction of aqueous solution of iron(III) nitrate nonahydrate
Crystalline iron(III) nitrate nonahydrate, Fe(NO3)3.9H2O, has a very pale violet color. When added to water, the crystals dissolve to form a brown solution. Treatment of this brown solution with ...
0
votes
1
answer
41
views
Reaction kinetics exercise for hydrogen iodide synthesis
The rate constant for the reaction of hydrogen with iodine is $\pu{2.45E-4 M-1 s-1}$ at 302 °C and $\pu{0.905 M-1 s-1}$ at 508 °C.
a. calculate the activation energy and Arrhenius preexponential ...
- 237
-3
votes
0
answers
33
views
In self ionization of water, why do we write concentration of water in expression for equilibrium constant? [closed]
If we take self ionization of water, then water is a solvent so why do we write concentration of water in equilibrium constant? Can't it be product of concentration of H+ ions and OH- ions? In that ...
- 35
-3
votes
0
answers
19
views
0
votes
0
answers
39
views
Do we group reversible reaction with all reactants and product solid as homogenous or heterogeneous equilibrium?
My personal thought is that they should be in heterogenous equilibrium as we define it as all reactants and products being of different phase (phase-their must not be a visible boundary) and solids ...
- 1
0
votes
1
answer
41
views
Static Equilibrium in an open and closed system
I've had a bit of confusion on whether static equilibrium can exist in an open system.
My textbook states (on modelling static equilibrium through water in a flask):
"Static equilibrium is shown ...
- 75
0
votes
2
answers
125
views
Acid dissociation constant from conductometric data
$\ce{0.007 M}$ aq. solution of anilinium hydrochloride had molar conductivity equal to $\pu{119.4 S cm2 mol-1}$, which became $\pu{103 S cm2 mol-1}$ when a few drops of aniline were added to the ...
- 136
3
votes
4
answers
577
views
Why do we say the position of equilibrium is shifted even when K is the same?
I realize that there are similar questions that have already been asked here, however none of them answer the question. The answers all say that (when K is the same) you "you haven't really ...
- 39
-2
votes
1
answer
46
views
metallic mercury is shaken with a solution of mercury(II) nitrate [closed]
Hi there, I am reviewing equilibrium.
About this question, I wonder if the chemical equation is wrong.
Because the description says 'a solution of mercury(I) nitrate is formed'.
However, in the ...
- 7
-1
votes
1
answer
53
views
What side does heat get added on in an equilibrium expression?
I know this is probably such a basic question with fundamental explanations and I can't help from overthinking.
So if we have an equilibrium would the addition of heat as in an increase in temperature ...
-4
votes
1
answer
58
views
What happens to the ions after dissociation in an aqueous solution? [closed]
I'm in high school studying about Buffer Solutions. We had an example of a solution made up of Ammonium Hydroxide and Ammonium Chloride for a Basic Buffer.
NH4OH ⇌ NH4 (+) + OH(-)
NH4Cl ⇌ NH4 (+) + ...
- 1
2
votes
1
answer
52
views
Why Michaelis Menten Assumption of equilibrium is necessary to integrate rate of ES production
I read in my textbook that the assumptions of equilibrium and of steady state used by Michaelis and Menten were simplifying assumptions intended to make the following equation one that can be ...
- 21
0
votes
0
answers
31
views
Is Ksp measured for covalent compounds as well?
A quick search on Google tells me that it is only used for ionic compounds but I think it should be used for some covalent compounds given that some of the covalent compounds also dissociate into ions ...
- 81
1
vote
2
answers
62
views
How to obtain the expression for residual Gibbs energy?
The property involved is Gibbs free energy, the equations that I wrote are presented in my text book Introduction to chemical engineering thermodynamics by Smith and Van Ness, Chapter 6.
The thing is ...
- 87
2
votes
4
answers
132
views
How can the Kw of water be constant?
I know in neutral solution, $\ce{[H+]}= \ce{[OH-]}= \pu{1.0 x 10^-7}$.
However, let’s say I add an acid like HCl. This will increase $\ce{[H+]}$, therefore it’s no longer $\pu{1.0 x 10^-7}$, but is ...
- 41
0
votes
1
answer
59
views
pH calculation of HCOOH +plus HCl solution
Question - What volume of $0.1 \ce{M}$ $\ce{HCl}$ solution should be
added to a $\ce{500 mL}$ of $\ce{0.5 M }$ $\ce{HCOOH }$ solution in
order to prepare an acid solution of $\text{pH}$ =$1.5.$ $K_a$...
- 189
2
votes
1
answer
120
views
Does it make any sense to graph 1/T versus ln(Kc)?
I calculated $K_c$ experimentally for the reaction $$\ce{CO2 + H2O -> H2CO3}$$ at different temperatures. Because $\Delta G =-RT\ln(K)$, I thought that graphing 1/T against $\ln(K_c)$ would give me ...
0
votes
3
answers
90
views
Confusion regarding spontaneous and non-spontaneous reactions
According to Wikipedia: "A chemical reaction is endergonic when non spontaneous. Thus in this type of reaction the Gibbs free energy increases."
My problem with that statement is the wording ...
- 276
-1
votes
2
answers
51
views
Question about computed equilibrium graph
When I was reading a paper about sulfuric acid decomposition,I couldn't understand this graph very well.(link)
The caption says concentration but the vertical axis says mole(not mole/L or something ...
- 677
-1
votes
2
answers
71
views
Higher or lower temperature to produce maximum yield of NH3(g) in Haber process
Question: In order to get the highest yield of NH3(g) in Haber process, should you use high or low temperature?
The answer in the textbook says lower temperature produces more yield of NH3(g) in Haber ...
0
votes
1
answer
67
views
Closed pressurized water vessel
Suppose we have a closed container not isolated from the external environment so that heat exchanges can occur on the lateral wall (mainly for convection). The water inside is pressurized by a gas (...
- 23
2
votes
3
answers
194
views
How to calculate the pH of a solution with addition of a complex
The scenario is this. I have $50$ mL of $0.1$ M $\ce{NH4^+}$ at a certain temperature which gives it a $K_a=5.2\times 10^{-8}$. To this solution, I add $0.02$ moles of $\ce{Cd(NO_3)_2}$. It is known ...
- 211
3
votes
0
answers
50
views
Does real-world gas phase chemistry use "concentration reaction quotients" (K_c)?
As a theoretical chemist, my entire exposure to reaction quotients and equilibrium constants ($Q$ and $K$) is through thermodynamics ($\Delta G^\ominus = - RT \ln K_{eq}$ and so on).
So as I started ...
- 131
-2
votes
1
answer
81
views
Why doesn't the ocean gradually turn into hydrogen and oxygen gas? [closed]
Maybe I'm wrong about this, but I thought I remembered from high school chemistry that all reactions are in equilibrium. Some equilibria are extremely far to the right or left, so they appear to react ...
- 1,623
0
votes
1
answer
114
views
Molar heat capacity of water at equilibrium
Molar heat capacity is defined as the heat energy given to one mole of substance to raise its temperature by 1 degree celcius (or 1 Kelvin)
Mathematically, $$C_{m} = \frac {q}{n\Delta T}$$
Here's a ...
0
votes
1
answer
62
views
Would the partial pressure of O2 in the system affect the rate of the decomposition of H2O2?
In my Bio 1 lab we studied the way catalase catalyzes the decomposition of H2O2 and at the end it asked me what conditions would affect the rate of the reaction. It was the type of question that ...
- 3
1
vote
2
answers
202
views
Understanding Reaction Rates and equilibria
As a high school student grappling with the interplay of reaction rates, Le Chatelier's principle, and equilibria, I have a question about a system that hasn't yet achieved equilibrium.
Specifically, ...
- 157
3
votes
0
answers
176
views
Equilibrium constant of the formation of ferric thiocyanate
I was reading the paper Relaxation Kinetics of Ferric Thiocyanate (Goodall et. al, 1972) and I came across a passage which read
$\space$ Reaction (1) is the simplest representation of the equilibrium ...
- 173
3
votes
0
answers
97
views
Derivation of the Van 't Hoff equation
I was reading the paper Relaxation Kinetics of Ferric Thiocyanate (Goodall et. al, 1972) and I came across the passage
Reaction (1) is the simplest representation of the equilibrium between ferric ...
- 173
0
votes
0
answers
49
views
Determining whether precipitation will occur or not and finding the concentration of a specific ion in a solution
The Ksp value of AY2 = 9.148 x 10^-2. I am having problem with calculating the concentration of ions. And without the correct concentration I can't find the Qsp/Kip so I'm stuck without them I can't ...
- 9
0
votes
1
answer
56
views
Can an electrode run out of the active species?
I have a background in solid state physics but am new to electrochemistry. I have been following the example of a physical chemistry (Mortimer) book that looks an electrochemical cell with a hydrogen ...
- 9
1
vote
0
answers
41
views
Why is it that in a buffer solution the equilibrium concentrations may be assumed to be the initial concentrations? [duplicate]
Considering the Henderson–Hasselbalch equation,
$$\text{pH} = \text{p}K_a + \lg \frac{[\ce{AcO⁻}]} {[\ce{AcOH}]}$$
$$\text{p}K_a = \lg \frac{[\ce{AcO⁻}][\ce{H⁺}]} {[\ce{AcOH}]}$$
Why are the values ...
- 11
0
votes
0
answers
52
views
Temperature-dependent pressure equilibrium constant of the heterogeneous water-gas shift reaction
In the course of my research, it became necessary to perform thermodynamic calculations involving chemical reactions. One of the chemical reactions is the heterogeneous water-gas shift reaction
$$\ce{...
- 9
1
vote
1
answer
82
views
Solubility of SrF2 in aqueous solution of NaF
This might be really simple question but I have no idea how to proceed to solve such kind of question.
The solubility product of $\ce{SrF2}$ in water is $\pu{8E-10}$. Calculate its solubility in 0.1M ...
- 23
1
vote
4
answers
233
views
How do I determine temperature and pressure rise whenever mols of gases are added in a isolated room?
Let's consider a fully isolated room, no gas or heat flowing from it.
We consider gases ($\ce{O2,N2,CO2}$) to follow the ideal gas law, and no chemical reaction occurs between them.
Pressure $p$, ...
- 31
-3
votes
2
answers
57
views
Change in Gibb's free energy at equilirbrium [duplicate]
I know the basic relation that ΔG=ΔG⁰+RTln(Q) where Q is the reaction quotient, my doubt is that if Q=1 at equilibrium then ΔG=ΔG⁰ but will ΔG=0 or ΔG≠0? As far as I know, generally at equilibrium Q=...
- 5
2
votes
1
answer
97
views
Equilibrium Solubility of CO2 in Aqueous Solution and its Dependence on H3O+ Concentration
The equilibrium solubility of $\ce{CO2}$ in an aqueous solution is given by three chemical reactions:
$$
\begin{align}
\ce{CO2(g) &<=> CO2(aq)}\label{rxn:R1}\tag{R1}\\
\ce{CO2(aq) + H2O &...
1
vote
3
answers
274
views
What does it mean Keq=1?
I’m struggling with a chemistry question related to equilibrium in a reaction. I don’t understand the meaning of $K_\text{eq} = 1$. After some research I found that when $K_\text{eq}$ is 1 it means ...
- 87
6
votes
0
answers
112
views
Which xylenes, if any, are immiscible with DMSO?
"Xylene" is reported to be immiscible with dimethyl sulfoxide (DMSO), according to a few solvent miscibility tables found online (chart 1, chart 2, chart 3). I have tried to locate some ...
- 792
0
votes
1
answer
99
views
Non-elementary reactions: Relationship between kinetic and equilibrium constant
As far as I understand, the equation for a kinetic equilibrium is always the same, and is given by:
$$K = \frac{\text{concentration of products}^{p}} {\text{concentration of reactants}^{r}}$$
Where $p$...
0
votes
0
answers
86
views
Why can we use stoichiometric coefficients in the equilibrium-constant expression? [duplicate]
I just studied the chapter on chemical kinetics on Coursera, wherein I was repeatedly admonished not to use the stoichiometric coefficients in the rate law formula. I was told that this formula has to ...
- 33
0
votes
1
answer
203
views
Gibbs free energy versus reaction progress plots
I am trying to make sense of these two graphs. They appear to have similar axes, yet display different curves.
Please let me know if this understanding is correct:
In the top image (x-axis = "...
- 11
-4
votes
1
answer
38
views
Difference in salinity and/or sugar content: Does it have a name? [closed]
Let's say that I put a tea infuser full of high-salt and/or high-sugar content, into a tea pot full of fresh water. I know that the salt and/or sugar will move from the infuser to the tea pot until ...
- 95
-2
votes
1
answer
75
views
Pressure before equilibrium = Pressure during equilibrium?
For example, let's say we have the equation $$\ce{PCl_3(g) + Cl_2(g) -> PCl_5(g)},$$ and the temperature is held constant.
Would the pressure in the container when equilibrium is reached be greater ...
- 59
1
vote
1
answer
89
views
What are the dissociation constants of hydronium and hydroxide ions? [duplicate]
Context
The answer to How to calculate Ka for hydronium and Kb for hydroxide?, water was regarded as solvent once and base (or equivalently acid) once while citing Reference 1 (1986) and made no ...
- 2,093
-3
votes
1
answer
121
views
If Qc> Kc how can forward reaction can take place
If Qc>Kc then there will be a net backward reaction but still forward reaction will take place. My problem is if Qc>Kc forward reaction will become non spontaneous right. So how can that happen, ...
- 13
-3
votes
1
answer
85
views
What if kc=1 will reactants concentration equals to product concentration [closed]
I read a book, it says if kc=1 it mean reactant concentration equals to product concentration at equilibrium. But I'm wondering that in kc expression we dont just use concentration of an element we ...
- 13
2
votes
3
answers
233
views
Change of equilibrium constant with respect to temperature
Suppose we have an arbitrary chemical reaction $A+B\rightleftharpoons 2C+D$ and its equilibrium constant at two temperatures $T_{1},T_{2}$ are $k_{1},k_{2}$. We can relate them as
$$\log\frac{k_{2}}{...
- 169
-2
votes
1
answer
161
views
Chemical Equilibrium and Sponteneity
Consider the reaction $$\ce{N2O4 <=> 2 NO2}.$$ The forward direction of this reaction is non-spontaneous and under standard conditions $\Delta G^\circ = \pu{4.76 kJ/mol}$. Suppose we begin with $...
- 157