All Questions
106
questions
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
-1
votes
3
answers
107
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
3
votes
0
answers
76
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, ...
- 3,684
-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 ...
2
votes
2
answers
147
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
-3
votes
1
answer
241
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
2
votes
3
answers
336
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
$$\log\frac{k_{2}}{...
- 169
4
votes
3
answers
1k
views
What is the basis for the relationship of Gibbs energy and extent of reaction shown in this graph?
How this graph of Gibbs free energy between reaction coordinate is made because because
∆G = ∆G° + RT ln Q
and since ∆G° and T is constant hence the graph should be like that of ln(x)?
Source: https:/...
- 143
0
votes
1
answer
120
views
Why change of gibbs energy per mole is zero at equilibrium?
I was reviewing this concept and thought of this: $\frac{dG}{dt} = \frac{\partial G}{\partial \xi}\frac{d \xi}{d t}$, for a reaction to be at equilibrium $\frac{d G}{d t}$ must be zero but I have ...
- 77
1
vote
0
answers
94
views
Unit of equilibrium constant in formula for Gibbs free energy change at arbitrary temperature
We know the relation for Gibbs free energy change of a reaction at any stage and any temperature
$$\Delta G=\Delta G^{\circ}+RT\ln Q$$
where Q is reaction quotient. Subsequently, we get the rate ...
- 169
6
votes
2
answers
479
views
Equilibrium constant vs Reaction rate constant
For a reaction, e.g.,
$$a X + b Y → c Z$$
Its reaction rate constant is
$${\displaystyle r=k_f(T)[\mathrm {X} ]^{m}[\mathrm {Y} ]^{n}}$$
where the exponents m and n are called partial orders of ...
- 81
3
votes
1
answer
166
views
Why does the equation for chemical potential apply to liquids and aqueous solutes?
The equation for chemical potential of a gas can be derived as such:
At constant temperature,
$$\mathrm dG = V\,\mathrm dP \label{eqn:1}\tag{1}$$
Substituting with the ideal gas law $PV = nRT$,
$$\...
- 360
0
votes
1
answer
906
views
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. ...
- 159
1
vote
1
answer
314
views
How does the rate equation account for solids and liquids?
The question is long because I wanted to include the whole thought process.
Given the hypothetical reaction:
$$\ce{ A(s) + B(aq) <=> C(aq) + D(aq)}$$
One would obtain the equilibrium constant:
$$...
- 360