All Questions
Tagged with equilibrium thermodynamics
275
questions
-4
votes
1
answer
73
views
What is the reason behind atoms/molecules in reversible reactions reverting back to its reactant state even if they have found stability? [closed]
If atoms and molecules aim for stability and equilibrium, then why do they feel the need to revert back into their original state once they have already found stability?
Example: $\ce{I2 + H2 \to 2HI}$...
- 13
3
votes
1
answer
113
views
Effect of Pressure on the Position of Equilibrium
The following general reaction proceeds with decrease in amount of substance, so increasing pressure should shift the position of equilibrium to the right.
$$\ce{2 A(g) <=> B(g)}$$
But let's say ...
- 47
3
votes
1
answer
95
views
Calculation of Reaction Extent as a Function of Pressure and Temperature: Issue with Activity-Based Approach
I'm working on modeling reactions involving combinations of hydrogen (H), nitrogen (N), and strontium (Sr) elements. I've obtained the temperature-dependent Gibbs free energy of formation, enthalpy, ...
- 31
0
votes
1
answer
121
views
How does cell potential change with temperature for positive enthalpy and negative entropy?
A recent United States National Chemistry Olympiad question asked:
A certain voltaic cell has a standard cell potential that increases with increasing temperature. Which best explains this ...
- 206
-1
votes
3
answers
103
views
How is it even possible that vapour pressure of liquid and vapour of solid are equal at freezing point? [duplicate]
My text book states The freezing point is defined as "the temperature at which the vapor pressure of the substance in its liquid phase is equal to its vapor pressure in the solid phase" Also ...
- 35
2
votes
1
answer
136
views
Determine equilibrium stability transition of a reaction (function of temp and concentrations)
I am trying to calculate and plot the stability of $\ce{Fe3O4 - FeS2}$ based on the chemical equation:
$$ \ce{Fe3O4(s) + 6SO2(g) + 16CO(g) -> 3FeS2 (s) + 16CO2(g)} \tag{1} $$
I want to plot the ...
3
votes
0
answers
75
views
Bancroft's point
In the last problem (Problem 10.43) within the problem section of Chapter 10 in "Introduction to Chemical Engineering Thermodynamics" (J.M. Smith, H.C. Van Ness, M.M. Abbott, McGraw-Hill, ...
- 3,671
-2
votes
1
answer
122
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Inconsistency in between Nernst Equation and Gibbs Free Energy Equation [closed]
Part 1 - Derivation of the Gibbs Free Energy Equation: [copied from this]
Using the fundamental equations for the state function (and its natural variables):
\begin{align}
\mathrm{d}G &= -S\...
-3
votes
3
answers
109
views
How salt helps to melt ice even when there is no dynamic equilibrium between water and ice?
I am a high school student and I am confused about freezing point depression.
We say that when in winter's it gets even colder than normal freezing point Temperature then we use solute to melt ice ...
1
vote
0
answers
54
views
Temperature dependence on the feasibility of an equilibrium
If we consider a reaction A + B ⟶ C + D, with $\Delta$S $>0$, then regardless of whether $\Delta$H is positive or negative, increasing the temperature will make $\Delta$H - T$\Delta$S more negative,...
- 21
2
votes
2
answers
130
views
Multiple equilibria
I was reading about multiple equilibria reactions and can't quite comprehend some things.
Suppose we have two reactions:
\begin{align}
\ce{A + B &<=> C + D},& K_\mathrm{eq} &= 10^{20}...
- 415
2
votes
2
answers
146
views
Boiling point, pressure, and Gibbs free energy
The water boiling process can be represented by the equation:
$$ \ce{H2O(l) → H2O(g)} \tag{1} $$
Since free energy depends on pressure
$$ \left(\frac{\partial G}{\partial P}\right)_T = V \tag{2} $$
...
- 27
1
vote
1
answer
119
views
Does Hess' law in standard conditions involve consuming all reactants?
The standard free energy change for equilibrium problems is relative to both reactants AND products starting at 1 molar.
Hess’s law takes the sum of the values for products minus the sum of the values ...
- 21
0
votes
1
answer
63
views
Mathematics behind the graph between Gibbs energy and extent of reaction
When the graph between Gibbs energy and extent of reaction is plotted, such a curve is obtained:
I am unable to understand how we got to the concavity of this graph (which can also be seen as the ...
- 79
2
votes
1
answer
163
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 ...
