Physics 32.7 Thermodynamic Potentials (4 of 25) What is Enthalpy?

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In this video I will explain enthalpy which is one of the thermodynamic potential. Enthalpy is the amount of heat (energy) absorbed (required) by the system to cause a change in the system, OR the amount of heat expelled by the system as a result of a change in the system.
Next video in this series can be seen at:
• Physics 32.7 Thermody...

[@CCC93772]

OMG!!!! I loved this!!!! I understand so much better now. Thank you for this video

[@MichelvanBiezen]

Glad it was helpful! And welcome to the channel!

[@catkat7310]

nice!!!this lecture makes sense sir.You explained the concept simple and clear.

[@MichelvanBiezen]

Glad to hear that

[@virtuality400]

After searching for tons of video finally find a 💎😭😭

[@MichelvanBiezen]

Glad you found our videos. (There are 9500 on this channel). 🙂

[@BentHestad]

Thanks for another great series, professor! Had an interresting task last autumn in our first course in thermodynamics here at NTNU, Trondheim: An evacuated, very solid steel box, room temp. and 1 bar around it, then you open a little hole in it, and air expands to 1 bar quickly within the box. But what will be the temperature inside the box when pressure have settled at 1 bar? Kept me awake for couple of days and nights, but really told me a lot about relation between internal energy and enthalpy! Merry Christmas to you and family!

[@MichelvanBiezen]

Thank you and thank you for sharing.

[@amirsoltani1297]

Very nice definition of enthalpy. Could you please, tell me some examples of delta V becomes negative?

[@MichelvanBiezen]

If we think of the system as a gas, then the volume will decrease when work is done ON the gas.

[@shakilcuchem]

It's like a diamond❤❤❤❤

[@MichelvanBiezen]

Thank you.

[@shakilcuchem]

@@MichelvanBiezen love from Bangladesh 🇧🇩

[@MichelvanBiezen]

welcome to the channel.

[@niddin4302]

sir i have a doubt why is there a need to define a new quanity that causes a change in the system . according to to the first law of thermodynamics we already have a relation that effects the systems with the change in heat

[@MichelvanBiezen]

I tend to agree with you. When I took thermodynamics for the first time, it seemed that there were about a half of dozen equations that described the state and the changes sligthly differently, when in essence they were the same or very similiar equations. They could have said, "the heat added = change in internal energy + work done by the system" instead of "enthalpy". But enthalpy is also used in chemical reactions, and therefore in a certain context it makes sense.

[@niddin4302]

Thank you sir. U made thermodynamics look like a child's play . Couldn't have done without ur videos thanks again

[@turtles38x19]

If the enthalpy of a system is a specific value. How to know what the change of the system will result?

[@MichelvanBiezen]

That is a very general question. When we get a chance, we'll add more videos to this playlist to make more of it clear.

[@pramithevans7088]

Thankyou sir ❤

[@MichelvanBiezen]

You are welcome. Glad you found our videos. 🙂

[@nthumara6288]

it seems like enthalpy and q in the first low of themodynamic then why we difine enthalpy when we have d

[@MichelvanBiezen]

Enthalpy is not part of the first law of thermodynamics.

[@arifullah7395]

Sir enthalpy nd first law of thermodynamics are the same concept of single coin than why not we use Enthalpy instead of first law of thermodynamics ...? Is there any difference between the two concept

[@MichelvanBiezen]

There is a slight difference and typically ignored during applications of the first law of thermodynamics. (It is mostly a theoretical concept).

[@honestman276]

Thanks from Bangladesh.

[@MichelvanBiezen]

You are welcome. Welcome to the channel! 🙂

[@shashikasandaruwan7706]

well explained thank you

[@MichelvanBiezen]

Thank you.

[@mayurijadhav9855]

Thank you so much sir . I have understand enthalpy very well... thank you

[@MichelvanBiezen]

You're most welcome

[@sadikselia1427]

Can someone please explain what is the difference between H (enthalpy) and Q (heat)

[@MichelvanBiezen]

The enthalpy of a system is the sum of the heat contained in the system and the energy required to push the atmosphere around the system out of the way to make room for it.

[@alperendemirci1346]

Sir hello i have a very Quick question. Hope you answer it. A particle of mass M is moving in the positive x direction with speed V in the laboratory reference frame. It spontaneously decays into 2 photons, with the original particle dissapearing in the process. Photon 1 has energy 233 MeV and photon 2 has energy 21 MeV. And the question has 4 parts but what i need to learn is What are the directions of each photon in the laboratory reference frame? Thank you

[@MichelvanBiezen]

Momentum must be conserved. And momentum of a photon is: p = E/c

[@MichelvanBiezen]

Assuming that the high energy photon moves in the same direction as the particle then the low energy photon must then move in the opposite direction.

[@itsnyrasworld]

Thank you for your efforts ❤

[@MichelvanBiezen]

You're welcome 😊

[@mostafamahmod53]

Thanks. But what is the difference between Q and H

[@mostafamahmod53]

Please ,is the enthalpy (h) the internal energy for the open system and (u) the internal energy for the closed system

[@MichelvanBiezen]

Q represents the heat added or removed from a gas. he gas + energy needed to expand the gas. When we are dealing with a liquid or a solid the difference between delta H and delta U is very small since the expansion upon heating is very small.

[@mostafamahmod53]

@@MichelvanBiezen thank you🤍🤝

[@ayushijha9634]

If already had heat why to introduce enthalpy

[@MichelvanBiezen]

It is more of a theoretical concept. Heat is more practical.