What is Enthalpy?

[@BensChemVideos]

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[@tylerriles3124]

I gotta say, as an HVAC tech working in the field trying to get a better understanding of enthalpy, you saying pressure is generally constant and work doesn't matter made this almost irrelevant to the real world application. This seems like a way to calculate how much an uninsulated window heats a house. Very frustrating.

[@william3371]

Thank you I have a Chem test this morning and this helped me, God bless you. Subscribed

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@william3371 you're very welcome! Hope you crushed it!

[@jonathanuis]

Ben, congrats, this is the most clear explanation about enthalpy I have even seen. I am a chemical engineer and people in my field just take for granted the word enthalpy but most of them do not understand the real concept (including me until today). thanks for your work doing such educational videos all the best from Germany

[@BensChemVideos]

Thanks for your kind words! Much love from the USA! 😃

[@dontForgetTheConstantC]

I spent a whole evening to find a clear definition. Finally, I got it. Thank you very much.

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You're very welcome! Thanks so much for watching 😀

[@daphnec4016]

Only video I've come across that makes enthalpy make sense. Other videos just recite the formula! Thank you.

[@BensChemVideos]

@@daphnec4016 so glad to hear that! Always good to know WHY! Thank you for your kind words.

[@agustinlawtaro]

There's thousands of videos that gives an intuition of entropy but this is the only that I found that gives, in the first minute, an idea of why is enthalpy useful. Thanks.

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Thank YOU! That's really helpful feedback! 😀

[@ciaramaeserafica798]

Its my first year in college and I LOVE YOUR VIDEOSSS i finally understand chemistry :)

[@thelegendofpro8038]

Bruh I’m studying this in my end of middle school

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Until today im still in college.. 😂😂😂😂😂

[@killua9369]

Have u graduated?

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Where are u now

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This was sooooooo useful! You explain things in a very clear way and it all make sense ❤❤❤❤❤❤❤❤❤please don't stop posting okra

[@Thiru-2006]

i have been just learning the formula without knowing the actual meaning of enthalpy. thank u very much for the explanation. love from India

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You're very welcome 😀

[@littlecesario]

My goodness this was life changing. Thank you!

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[@khalidali9356]

Great Explanasion

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Thanks! 😃

[@afshinghiasvand]

Thank you so much. Your description was clear and it was very helpful for me.

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[@richietozier5123]

this was super useful! thanks!

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You're very welcome! Thanks for watching 😀

[@rubyrichiez1298]

Really helpful do you have a video where you go more in detail? I’m suffering through physical chemistry right now and the integrals are killing me it’s super hard to find any physical chemistry stuff on youtube

[@Mehdi_Hammar]

You can check the TMP Chem channel, it's very very interesting ;)

[@masaqader]

Awesome content! This explained it so clearly, you're amazing at teaching!

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Thanks, glad you enjoyed it! 😀

[@brittneywilson3369]

just wanna say I LOVE YOU! YOU'RE SO AWESOME and helpful with chemistry!!!

[@earthn1447]

Thank you! Great explanation! Will help with my Climate Reality Presentation!

[@cibernerd]

thanks, clear and useful explanation !

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You're very welcome! Many thanks for watching 😀

[@dhivyamaalya]

Wow, you summed it up in a very easy way!

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[@opmanwingchun]

Thank you Ben.

[@Latif.Kakule]

Thank you so so much!! I finally get it Thank you!!!

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[@bic1349]

Amazing explanation! Subscribed 😎

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Many thanks! 😃

[@User4o3p93ghvjkaehvji]

Very useful 😃

[@BensChemVideos]

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I love your videos, they're excellent!!

[@ItachiUchiha-sc2yo]

Nice video.. Thank you

[@abdelz1617]

Great video, thank you!

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[@looppaddleanimation9488]

Thanks man. It was really helpful

[@BensChemVideos]

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[@chikeluba]

Thank you. You made that so easy

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[@darioobandohidalgo]

Thank you, Steph Curry for the video. Congratulation to you for your first Olympic medal!

[@mizutanishizuku6006]

What is the meaning of Change in Enthalpy when the pressure is not constant? In some problems deltaH was given directly by n×cp×deltaT even when the process was adiabatic and pressure varied

[@carultch]

Enthalpy is a state function, that doesn't depend on the path taken. You can heat the gas at constant pressure to give it its full change in enthalpy, and then take an isothermal process to the final condition. Isothermal processes with an ideal gas have no change in enthalpy. This will have exactly the same change in enthalpy, as if you take a process with varying pressure. The heat and work will be different, but the change in enthalpy will not. The change in enthalpy is still useful for such a process. You see this parameter used, in turbines and compressors, where the process ideally is adiabatic. The rate of work done on the gas compressing it (or by the gas expanding it in a turbine) equals the mass flow rate times the change in enthalpy. Since it is an open system process, rather than a closed system process, we need to account for energy through enthalpy, rather than internal energy.

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Thank you Sir

[@ilimselyardm9698]

Thank you sir, may Allah bless you

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[@wukf1]

awesome man! thank you!

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[@AK-op4be]

Thanks✨

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[@MrAminmohamed]

Thanks a lot

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[@userr_aa]

it's not just useful,instead it's tooooooo useful

[@BensChemVideos]

Thank you for your kind words, and thanks for watching! 😀

[@casaxtreme2952]

Good explanation! The only thing that bugs me is the capital and lower case letters. I learned that capitals are total values and lower case letters are "per mass". Which means that the q and w should be capital or all the others lower case.

[@priyanshuostwal5039]

so what does the steam table value gives us mean? Say at 300C and 5bar pressure, the enthalpy value of water/steam is 2534kJ/kg (NOT ACTUAL VALUE). So what is this value? Does it say if we raise the temperature of 1kg liquid at a constant pressure of 5 bar from 0C to 300C, we will need 2534kJ ??

[@BensChemVideos]

I don't understand the question. Could you rephrase it?

[@carultch]

The datum at which enthalpy is defined as zero, is arbitrary. You need to use steam tables with the same reference point. It's common to define it at zero at a point such as 0C and saturated liquid. Refrigeration tables define it at zero at -40C and saturated liquid. It is only difference between enthalpy values in steam tables that means anything. And an application of this, is finding the power produced expanding the steam in a turbine.

[@legend-uj2dp]

thanks so much man

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[@athiradas1002]

Thank you ❤️

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[@MIFZALMOHAMADNAZREL]

thank you

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[@stoneguardian9292]

me reading your title for the first time was Benis

[@BensChemVideos]

Lol nice

[@jenniferwang946]

Wait so enthrall is basically heat released or absorbed under constant pressure???

[@BensChemVideos]

Yes, enthalpy is basically the absorption or release of heat under conditions of constant pressure. Thanks for watching!

[@jenniferwang946]

Ben's Chem Videos oh thank you so much 😊

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[@daphnec4016]

Why is change in enthalpy equal to q+w-w when w = -p delta V? Wouldn't it just be change in enthalpy is equal to q+w(-p delta V)?

[@BensChemVideos]

@@daphnec4016 I think the video explains it better than I could in a comment, but I'll give it a shot. DeltaH is equal to deltaE + P * deltaV If deltaE is equal to q + w (first law), then delta H is equal to q + w + P*deltaV. If w = -P*deltaV, then POSITIVE P*DeltaV is equal to -w Substituting -w in place of the P*deltaV term in the enthalpy equation gives... DeltaH = q + w - w The w's cancel, and we're left with q.

[@daphnec4016]

@@BensChemVideos thank you!

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@@daphnec4016 you bet!

[@mysticjaarse]

Mr Ben I thought the symbol for Internal Energy was H. I see you are using E. Are we allowed to use E?

[@BensChemVideos]

I've seen both "E" and "U" for internal energy. I've never seen "H" used to represent internal energy. It doesn't matter too much what symbol you use, as long as you and those with whom you communicate all agree on terms.

[@mysticjaarse]

@@BensChemVideos thank you, I think I was confusing it with enthalpy sorry : )

[@estherkatentazimba4322]

Is work always negative even when the surrounding is the one that does work on the system??...

[@BensChemVideos]

If the system is doing work on the surroundings, then work is negative. If the surroundings are doing work on the system, then work is positive.

[@carultch]

The sign convention is arbitrary, and depends on what standards you are using. I'm accustomed to the heat engine standard, where heat added to the system is positive, and work done by the system is positive.

[@freshgamingreviews]

really helpful thanks.. my OCD ass tried to scratch that red dot away tho

[@BensChemVideos]

You're very welcome! Many thanks for watching 😀

[@VegitaBleEater]

To sum it up Enthalpy is the way to say it is the change in heat. Not exactly but yeah.

[@carultch]

Enthalpy is the energy needed to create a substance (internal energy U), plus the energy needed to make space for the substance (P*V).

[@J5izon]

I’m getting lost at the end. How did we get “w-w”?

[@shorts28793]

enthalpy ko energy khte h ky

[@daryadil8035]

It was better to take work negative in the first law's equation.

[@slttttt]

If enthalpy is only defined for constant pressure then why do they talk about enthalpy in other processes and what does enthalpy mean in other processes

[@carultch]

Enthalpy is a state function, that doesn't depend on the path taken. You can heat the gas at constant pressure to give it its full change in enthalpy, and then take an isothermal process to the final condition. Isothermal processes with an ideal gas have no change in enthalpy. This will have exactly the same change in enthalpy, as if you take a process with varying pressure. The heat and work will be different, but the change in enthalpy will not. The change in enthalpy is still useful for such a process. You see this parameter used, in turbines and compressors, where the process ideally is adiabatic. The rate of work done on the gas compressing it (or by the gas expanding it in a turbine) equals the mass flow rate times the change in enthalpy. Since it is an open system process, rather than a closed system process, we need to account for energy through enthalpy, rather than internal energy.

[@jenniferwang946]

High school AP bio freshman’s anyone ??? 😭

[@josenava4555]

Hi

[@RashmiranjanDas-yw3pu]

Banda

[@josenava4555]

I still don't understand

[@BOB_VOX]

I hope you understood after 7 years

[@PulkitGupta-g2t]

😂

[@mr.beehere1808]

Here 9 years later using this vid to study for my AP chem test🫶 updating later what my score is

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Best of luck!

[@mr.beehere1808]

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