Thanks Mike H, that was a good reminder of something I knew/should have known. I get confused thinking about it each time it comes up.
Can you be a little more concrete? Let's say I wanted to measure the standard enthalpy change of dissolving sucrose in water. The standard states of pure...
This is coming from junior-level physical chemistry.
Lots of thermodynamic properties of reactions involving solutions are tabulated under standard conditions; I'm particularly thinking of standard half-cell voltages, but any property will do.
How do you make, say, a sodium chloride...
Fill a glass with water and cover it. The water starts to evaporate. It will evaporate until a characteristic "vapor pressure" of that compound is reached. For water this is about 24 mmHg at room temperature. There is now an equilibrium between liquid and vapor, at a pressure and...
When you learn about phase diagrams of pure substances, you learn that the liquid and gas phases are in equilibrium only along the line separating the pure liquid and pure gas regions.
But if you have a sample of liquid in a closed container with some empty space in it, that empty space...
Thank you, atyy. This was exactly the problem I was referring to, though many physical chemistry texts have something almost the same (usually an expansion) with little details hid under the table. I am going to have to read this whole thread that blew up while I've been busy with something...
Andrew, your immediately prior comment was excellent. (For the record, you have a typo in your Step 3, change "Determine the reversible path..." to "...irreversible path...".)
However, isn't there a flaw when you assume the work done is the same in the reversible and irreversible processes...
Thanks for the reply, atyy. I understand the qualitative difference between the processes. However I want to understand the textbook justification for using ΔS=q/T to calculate entropy change of the SURROUNDINGS for an irreversible process. It seems that if the system is in the same final...
The textbook examples I am citing ALL go against what you say here, which is why I'm confused. Quite explicitly, the initial and final states of the system are identical comparing the reversible and irreversible processes, so they can say the ΔSsystem values are the same. BUT the irreversible...
Trying hard to understand a basic textbook model meant to illustrate that entropy (of the universe) increases for irreversible processes. Help me out please?
I get this part: A gas is compressed isothermally (constant T) and reversibly, getting worked on and expelling heat. To calculate ΔS...