725 reputation
514
bio website kemiisto.blogspot.ru
location Oslo, Norway
age 29
visits member for 3 years, 10 months
seen 7 hours ago

Aug
18
comment Why is thermodynamic equilibrium not reached by the system during a thermodynamic irreversible process?
Could you update your answer by quoting the definition of a reversible process from your book and also what is exactly said about irreversible processes being not in equilibrium?
Aug
17
comment Why is thermodynamic equilibrium not reached by the system during a thermodynamic irreversible process?
And finally, at the end of the day it all comes done to definitions, which you did not provide. Actually, some sources define a reversible process as a quasistatic process without entropy production. Thus, a system in a reversible process is always in equilibrium by the definition. A reversible process is nothing but a special limiting case of a quasistatic process. In an irreversible process a system might or might not be in equilibrium depending on is the process quasistatic or not.
Aug
17
comment Why is thermodynamic equilibrium not reached by the system during a thermodynamic irreversible process?
Secondly, thermodynamic equilibrium is reached in an irreversible process. Yes, it is reached at the very end of the process, but it is reached. Reading the body of your question I think you meant to ask why a system is not in equilibrium during an irreversible process. But such question has a little sense since a system actually can be in equilibrium during an irreversible process. A quasistatic process (a process in which system is all the way in equilibrium) might be irreversible.
Aug
17
comment Why is thermodynamic equilibrium not reached by the system during a thermodynamic irreversible process?
First, thermodynamic and thermal equilibrium are different things. Thermodynamic equilibrium implies thermal equilibrium, but the converse is not true. So be careful with using these terms interchangeably (thermodynamic equilibrium in the title and thermal in the body).
Aug
11
comment Which form of the first law of thermodynamics should I use?
@Manishearth sure. Actually, I did it already when wrote the comment about downvoting. Look at my answer below for details.
Aug
11
comment Which form of the first law of thermodynamics should I use?
Sorry, but -1 for $\Delta Q$ and $\Delta W$.
Aug
11
answered Which form of the first law of thermodynamics should I use?
Aug
4
revised Are isobaric, isochoric, and isothermal processes quasistatic by definition?
added 576 characters in body
Aug
4
accepted Are isobaric, isochoric, and isothermal processes quasistatic by definition?
Aug
4
comment Are isobaric, isochoric, and isothermal processes quasistatic by definition?
Let us continue this discussion in chat.
Aug
4
revised Are isobaric, isochoric, and isothermal processes quasistatic by definition?
added 1916 characters in body
Aug
4
comment Are isobaric, isochoric, and isothermal processes quasistatic by definition?
As I understand it, say, for an isothermal process the presence of a thermal bath is not enough. The process should also be performed slowly enough that the heat liberated by a system can be fully transferred to its surroundings, thus, keeping temperature of the system constant.
Aug
4
comment Are isobaric, isochoric, and isothermal processes quasistatic by definition?
my question is essentially the following: what is the meaning of the phrase that some quantity "is held constant" for a non-quasistatic process, during which this quantity is not even defined? After reading reply by Count Iblis, I have a feeling that the phrase that some quantity "is held constant" should be taken literally only for quasistatic processes, while for non-quasistatic it simply means that final and initial values of the quantity are equal to each other.
Aug
4
comment Are isobaric, isochoric, and isothermal processes quasistatic by definition?
So, if I understand you correctly, when we say that, for instance, temperature is kept constant during a process, the meaning of this phrase is actually different for quasistatic and non-quasistatic processes. For a quasistatic process we indeed mean that $T$ has the same value all the time during the process, while for a non-quasistatic process we simply mean that $T_f = T_i$, or, $\Delta T = T_f - T_i = 0$. Am I right?
Aug
3
comment Are isobaric, isochoric, and isothermal processes quasistatic by definition?
No, I don think so. As I mentioned, even to meaningfully speak about pressure, the system must be in equilibrium. And besides, I could not tell for all the examples you provided, but one with Carnot cycle is wrong: isothermal expansion/compression in Carnot cycle are reversible, and thus, quasistatic. That is for sure.
Aug
3
asked Are isobaric, isochoric, and isothermal processes quasistatic by definition?
Aug
2
revised Electron shells in atoms: What causes them to exist as they do?
added 1012 characters in body
Aug
2
answered Electron shells in atoms: What causes them to exist as they do?
Jul
23
accepted Fock matrix elements for RHF formalism
Jul
23
comment Fock matrix elements for RHF formalism
Ugh! Yes, of course. Just was fooled by too much extra stuff on top of otherwise pretty simple expansion. Thanks!