All Questions
19 questions
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Is entropy constant when no heat is transferred?
Does entropy remain constant in when no heat is transferred between the system and surroundings?
If I do only mechanical or electrical work to change the properties like the volume of the system, ...
0
votes
1
answer
58
views
Entropy change in isothermal reversible expansion
So, this question is of JEE Mains 2023 exams.
One mole of an ideal gas at $350K$ is in a $2.0L$ vessel of thermally conducting walls, which are in contact with the surroundings. It undergoes ...
- 13
-1
votes
1
answer
75
views
Spontaneity of endothermic reactions [closed]
I see the Gibbs Free Energy explanation everywhere, but is there an intuitive explanation of how endothermic reactions can happen spontaneously? It seems intuitively reasonable that heat flows from ...
- 17
0
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3
answers
991
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Is q=0 for irreversible adiabatic process?
Well, I am a little bit confused about this question. I learn that reversible adiabatic processes are isentropic. So $\Delta S=0$. Through $\Delta S=\frac{ q}T$, we can say that $q=0$. But if you take ...
- 13
1
vote
2
answers
5k
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What is the entropy change in isochoric process
I have studied that entropy increases with increase in temperature and it decreases with increase in pressure but in case of isochoric process both are happening at the same time but still the overall ...
- 29
0
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2
answers
77
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How exactly is heat supplied in an isothermal process
How exactly is heat supplied in an reversible isothermal process. If the temperature of system and surroundings always remains the same, then how come surrounding is supplying heat?
I studied that T ...
- 29
-5
votes
1
answer
224
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Is delta S of universe always 0 when an ideal gas undergoes an isothermal irreversible process?
Since for an irreversible process,
$$dS_\mathrm{Surrounding} =-\frac{\text{dq}_\mathrm{irr,sys} }{T_{\text {surr }}}\tag{1}$$
where $\text{dq}_\mathrm{irr,sys}$ is heat exchange of system
and $-dq_\...
- 35
2
votes
0
answers
72
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Prigogine vs. Bronsted and the minimum entropy production principle
I apologize for the length of this question that was asked here prigogine-bronsted but got no reply; anyhow, Bronsted's name is much better known among chemists than among physicists...
Prigogine's ...
- 567
0
votes
1
answer
156
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What is heat bath here?
At the beginning $\pu{1 mol}$ of air is compressed to $\pu{3 atm}$ at a of temperature $\pu{523 K}$. After a random process, the pressure of the air equates to $\pu{1 bar}$ at a temperature of $\pu{...
- 203
4
votes
1
answer
2k
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Entropy change during electrolysis of water
Consider the electrolysis of water reaction:
$$\ce{H_2O -> H_2 + 1/2O_2}$$
At room temperature and atmospheric pressure, the change in enthalpy of this reaction is $\Delta H = \pu{+286 kJ mol-1}$. ...
- 251
0
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1
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386
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Why is enthalpy and not heat released by system used while calculating entropy of surroundings?
While finding the sum of change in entropy of the universe and thus defining Gibbs free energy, why is the change in entropy of surrounding the negative of enthalpy of the system divided by the ...
- 27
6
votes
3
answers
22k
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What is the relationship between entropy and heat capacity?
The molar heat capacity of hydrogen gas and deuterium gas are nearly the same, $\pu{28.8 J K-1 mol-1}$ and $\pu{29.2 J K-1 mol-1}$, respectively, but the absolute entropy of deuterium ($\pu{145.0 J K-...
0
votes
2
answers
108
views
Clarification required on whether to use $C_v$ or $C_p$ in this question on finding entropy change
$1 \text{ mol}$ of an ideal monoatomic gas at $300 \text{ K}$ is subjected to a reversible isentropic compression process until final temperature reaches $600 \text{ K}$. If initial pressure is $1 \...
- 383
3
votes
2
answers
350
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Can the change in the entropy of the surroundings always be obtained by dividing heat transferred by the temperature at which the transfer occurs?
Consider $\pu{1 mol}$ of an ideal monoatomic gas going through reversible isochoric heating from $\pu{100 K}$ to $\pu{1000 K}$.
Calculate $\Delta S_\pu{sys}, \Delta S_\pu{surr}.$
$$\Delta S_\pu{sys} =...
- 43
6
votes
2
answers
2k
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Entropy of surroundings and heat
Apparently the entropy change of a system can be found by
$$\mathrm dS=\frac{\mathrm\delta q_\mathrm{rev}}T$$
I am slightly confused about this because I have seen this being used when the temperature ...
- 1,717
3
votes
1
answer
6k
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Thermodynamics of DNA double helix formation?
The entropy of a system decreases when 2 single stranded DNA molecules come together and form a double stranded molecule. For this to occur the total entropy of the universe must increase. Thus, heat ...
- 31
0
votes
0
answers
119
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Entropy and Heat Capacity Trend in water
It is my understanding that entropy and heat capacity essentially measure the same thing. Since entropy is the ratio of heat (translational, rotational, vibrational movement) to temperature (...
- 1,620
3
votes
1
answer
3k
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Calculating entropy change of surroundings
I have seen many similar questions but have not found my answer. Why do we use the actual heat involved in the process to calculate entropy change of surrounding? The only answer I can think of is ...
- 782
1
vote
0
answers
2k
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Entropy change of surroundings
The entropy change of a system is given by
$$\mathrm dS=\frac{\mathrm dq_\text{rev}}{T}$$
which at constant temperature is
$$\Delta S=\frac{q_\text{rev}}{T}$$
I also learned that the entropy change ...
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