Making sense of temperature-entropy diagrams

This video discusses the key features of temperature-entropy diagrams and how to use them to represent different types of thermodynamic processes.
Link to the diagram: commons.wikimedia.org/wiki/Fi...

[@chivo2468]

Awesome video. Had been trying to understand the diagram in books and "easy examples" until I came across this. Thank you and I hope you're still creating material to this day. Subscribed.

[@youthermo2951]

Thank you very much for you kind comment. The latest videos of the channel have been in Portuguese but we plan to post videos in English again soon.

[@beyondscience004]

That's just it;straight to the point...awesome

[@youthermo2951]

Thank you very much. We are glad that the video was useful to you.

[@AlphatecEngineering]

Great video folks! thanks for sharing it!

[@lookwhathappenyougotmeaski6961]

amazing video! thank you very much

[@brandonmartin3297]

good shit mate

[@hamzamohamed7935]

Thank you for simple yet informative video

[@youthermo2951]

Thanks for your comment.

[@gizemkacann]

many thankss for wonderfull explanationn!!!

[@thulanithosalya]

Thank you so much♥🙏

[@paulpolito1438]

thank you

[@MrMatmulan]

Percebi que era brasileiro pelo sotaque hahahaha, ótimo vídeo

[@camilamaeses6733]

Can you give examples on you would determine values based on the diagram?

[@youthermo2951]

This is a diagram for a pure substance. If it there is only one phase, you specify two properties (e.g., T and S, or P and S, or T and P, etc...). Once you locate the point in the diagram that matches your specifications, the other thermodynamic properties can be found from the diagram. If there are two phases, that is, a condition below the "dome", the specification of a single variable - for example, T - allows you to determine the phase equilibrium pressure, and the specify entropy of the liquid and vapor phases in equilibrium. If you want to determine the relative amounts of the two phases, you need an additional specification, which can be, for example, the specific entropy of the system or the quality (vaporized fraction).

[@user-le2yx1wb2z]

what is the isobar in the sub cooled liquid region also?

[@youthermo2951]

They would follow the trend of the lines outlined to the left of the saturated liquid line. Note that for condensed phases - liquids (far from the critical point) or solids - the entropy is quite insensitive to pressure. This means that "moving to the left" along a line of constant temperature - that is, decreasing the entropy - needs large pressure increases.

[@taseenhaider3961]

How the pressure variation is represented in the dome if it's inclined line from 2 to 3 at 4:38

[@youthermo2951]

Thank you for your question. Points within the dome have two phases in equilibrium. According to Gibbs' phase rule, we have that F=C-P+2, where C is the number of components, P is the number of phases, and F is the number of degrees of freedom, that is, the number of intensive variables you need to specify to set the state of the system. For a pure component (C=1) in vapor-liquid equilibrium (P=2), we have that F=1-2+2=1. Having F=1 means that you can only specify the value of one intensive variable; the values of all other intensive variables of the phases will be the same regardless of the phase amounts. The line between, points 2 and 3 is horizontal, that is, all points of this line are at the same temperature. As F=1, these points will also be at the same pressure. Kind regards from the YouThermo Channel.

[@qwezxc23456]

Thank you sir

[@youthermo2951]

You are welcome, thanks for your comment.

[@nigeljohn6676]

How are points 2 and 3 ISO-Baric,.. they are completely different temperatures!

[@youthermo2951]

Points 2 and 3 are at the same horizontal line, thus, they are at the same temperature. In addition, they are at the same pressure because if the temperature of a pure substance remains constant in the two-phase, it is because the pressure remains constant too, according to the Gibbs phase rule.

[@cookiesncream8490]

thanks sir

[@youthermo2951]

You are most welcome, Cookies n Cream!

[@pukhrajmansion8445]

Good presentation Good explanation PL translation in Hindi language

[@youthermo2951]

Thanks for the comment. About translating to Hindi, as we have no knowledge of the language, we cannot review Google's automatic translation, which is good but far from perfect. Sorry.

[@user-le2yx1wb2z]

where is the sub cooled liquid region?

[@youthermo2951]

It is to the left of the saturated liquid line. Nonetheless, observe that water with low temperature and low entropy value may be in a solid state, but this diagram does not represent the solid-liquid equilibrium line. Thus, by just using this diagram, one cannot tell the condition in which such a liquid-solid transition would take place.

[@N330AA]

This is great, but the accent was a little difficult to understand on some of the technical terms.

[@philmybutup4759]

U brazilian?

[@youthermo2951]

Yes, we are Brazilian.

[@philmybutup4759]

@@youthermo2951 nice me too I could tell from the accent haha