PV diagrams - part 2: Isothermal, isometric, adiabatic processes | MCAT | Khan Academy

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24 мар 2015

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Комментарии : 104

@secondo92 7 лет назад

Holy sh** this was so well explained that even my cat would understand it!

@Destroyer9623 9 лет назад

would be good to add that the reason an adiabatic process is steeper than the iso-thermal process is due to the decrease or increase in gas particle velocity (which affects pressure) caused by the decrease or increase in temperature.

@JhaAtiksh 4 года назад

Was literally gonna ask this, my g

@DaringToast Год назад

thanks for the info, i had just begun wondering why pressure ended up higher for adiabatic expansion

@AgEyal 7 лет назад

You saved my life.

@golddigger0325 7 лет назад

Thank you for explaining so perfectly!

@cutler610 8 лет назад

Awesome video, just what I was looking for!!

@makahragayle8973 6 лет назад

Thanks for explaining these so well!

@dragowolfx 8 лет назад

ihave my thermo exam today thanks

@nandhakumars680 5 лет назад

Nice video which I understand this PV diagram for the first time thanks a lot good one 👍😍

@abhinavrauthan5181 4 года назад

What a tremendous !!! video best explanation ever!!!😇

@vortyx090 8 лет назад

Thank you very much...!!!!!

@hyuckkcuyh 2 года назад

soooo useful, I love this channel

@cathytaaf4840 4 года назад

I am so grateful for finding this video haha. Thanks!

@clayton8945 4 года назад

This is a really good video. Very clear and easy to understand.

@sonalirajput832 4 года назад

Omg..... U guys are so good at teaching 👍👍👍👍🙏🙏🙏🙏

@briannguyen6994 3 года назад

I wish there were more physics derivation videos from you specifically

@sarakhan3151 7 лет назад

thank you!

@ravilkhateek4999 5 лет назад

Well done ... Good explanation

@user-rw5pb2zb3l 6 лет назад

Do you now somthing ...u are awesome....thank sooo much

@ngumamah4477 2 года назад

So easy to understand

@coolmonkey619 3 года назад

Why does this not have more views

@yazadpardiwala687 3 года назад

7:40 You are a) extremely good at your explanations and b)very enthusiastic/funny at times

@aqsamustafabutt5400 7 лет назад

rest of theexplanation was very good

@diegoarana5862 3 года назад

this is very helpful when your teachers method of teaching is reading word for word off a PowerPoint and jarringly bouncing between slides constantly.

@rajendrapathak760 7 лет назад

All other vids kept confusing me.TYSM

@14aravindlochaner24 6 лет назад

Thank you thank you thank you very much

@dipakmudi3877 6 лет назад

thank u for help me

@cmhardin37 4 года назад

Thank you good sir. 👍🤘

@123lebornjames 8 лет назад

ohhhhhhhhh my god thank u!

@mikesmate6672 6 лет назад

Hi quick version of getting work in an Isothermal process when given the change in V ,number of moles and the temperature is using the equation W=nRTln[vf/vi];

@chakia4347 3 года назад

Thank u

@geonwoo1213 5 лет назад

nice!

@lodi8294 4 года назад

thank you

@atulprakash416 2 года назад

excellent

@bbmeme2010 7 лет назад

Well Done - thank you for explaining thermo and making it easy to apprehend. Where were you when I was in undergrad?!

@hisyamhasbi8257 4 года назад

Is apprehend means the same thing as i think it means?

@DuuuuuudeStopthat 6 лет назад

I shouldve watched your vid before I spent 3 hrs of my life trying to figure out what these three are.

@engineerstrange4447 8 лет назад

Hey can u please tell 🙏🙏🙏. Where do u write this I mean what is the software.

@arstudios6883 3 года назад

V good

@malawby 4 года назад

Does the GHE effect earth's temperature, or is earth's mean temperature of 15 C controlled by the atmosphere's mass and pressure from gravity?

@amirthavarshiniy6666 Год назад

I can't believe these videos are uploaded 7 years ago

@zaidahmed4800 4 года назад

helpfull

@anirudhstarc7234 7 лет назад

Thanks a lot!

@user-nk1cz4fk1p 7 лет назад

Hi, please take note that there is a mistake at 12:11. both isothermal and adiabatic curves should be single arrow. during compression process, the work done of isothermal process is less than the work done of adiabatic process, so the adiabatic curve should above isothermal curve in the revers way.

@connecteddthoughts 7 лет назад

No, that's not a mistake. He used two arrows to symbolize compression and expansion in both isothermal and adiabatic processes. At least, that's what I think.

@DaveShree 6 месяцев назад

Do you think that internal energy remain same and work done by heat exchange in isothermal process, then think again. Heat exchange takes place when there is difference in temperature but in isothermal, temperature is same. Work done is at cost of internal energy, change in pressure.

@viraldunia7905 3 года назад

brother. what is the name of this Software. you are writing like pen by mouse Amazing.

@nikko-kun643 6 лет назад

wll explained

@barahui9 3 года назад

Thank you for this video. My professor thought it was cool to use a shitty graph and an unintuitive explanation to help us understand this.

@Arsalankhan-mv7ng 6 лет назад

👌👌👌

@JuAnKing24 6 лет назад

isn't it delta U = -W since work is done onto the system cause work isn't done BY the system?

@nayanikakundu7824 6 лет назад

Actually, this depends completely on your perception. Conventionally, when work is done ON the system, it is taken to be positive, because, the system gains energy as, U=Q+W. On the other hand, when work is done BY the system, it is taken to be negative, as energy is lost by the system, giving rise to the relationship, U= Q- W. However, if you take the first law of thermodynamics as: U= Q-W, then, your assumptions is correct. If work done on the system is taken as negative, then, U=Q-(-W) i.e. U= Q+W. This completely depends on your perception, and honestly, convention does not matter as long as your conception is sound.

@DonSyndrome 5 лет назад

Damn good explanation. I studied engineering at Cornell. Trying to coach my son’s Science Olympiad Thermodynamics team.

@hisyamhasbi8257 4 года назад

Holy fuck, thanks man, truly from the ravine of my heart!!!!

@thushara765 5 месяцев назад

❤

@Abdulrahman-wo2ob 8 лет назад

For some reason, I thought the isothermal & adiabatic curves are switched, meaning tha adiabatic requires more work. I guess I was wrong.

@darkop8293 2 года назад

This was a good video but I think the equation for (delta U=Q+W) is wrong I think it's suppose to be minus

@jairabelleventurillo9998 4 года назад

isn't it that the formula for 1st law of thermo dynamics is Q= change in U + WORK? how come that change in U is now equal to heat plus work. ? it should be Q-W ? please correct me if I'm mistaken. Thank you.

@Gudi923 3 года назад

The equation is U= Q + W and the W can be positive or negative depending on what the gas does. If the gas did the work, then work is negative. If the work was done on the gas then the Work is positive. Hope that helps

@Starfighter-x2s 3 года назад

8:20 you mean deltaQ=U+W

@MuhammadQasim-fu4hb 2 года назад

I thought the first law of thermodynamics was delta U = Q - W

@nithin884 7 лет назад

How is pressure constant in Isochoric process?

@carultch Год назад

It isn't. It is volume that is constant in an isochoric process.

@aqsamustafabutt5400 7 лет назад

why adiabatic graph is more steeper?????????

@rickandelon9374 5 лет назад

It is because of the instant action required to do it. NOT SURE BUT!

@carultch Год назад

Here's the derivation of the adiabatic condition: hyperphysics.phy-astr.gsu.edu/hbase/thermo/adiabc.html#c1

@Akbarwayse 8 лет назад

At 8:22, did you mean that U = Q - W?

@dingleberrys232 6 лет назад

Although i didnt ask the question, thank you for your reply. I was getting proper confused, but now i understand.

@muhammadhassamkhan2331 4 года назад

I am stuck with first law of thermodynamics because of its mathematical expression, some are using like above expression which is u= Q+w and remaining are using U= Q- W

@francisjosephlarita2818 4 года назад

They put negative on it because of W=-P(Vf-Vi) iguess?.

@suhani715 Год назад

It's just some difference we have in subjects ...like the plus one is for phy and negative for Chem.....it's just differs on tge respective of where you are seeing or basically the point of view :)

@md.ahanafibnayakubsajim9782 6 лет назад

This is a isothermal process. So the eqution should be like dQ=dW(where du=0)

@harlymoon452 6 лет назад

Sajim Ahamed no I think it should be W=-∆U where (Q=0)

@md.ahanafibnayakubsajim9782 6 лет назад

harly moon i need sometime to think about it.

@williamnathanael412 6 лет назад

harly moon isothermal means there is no change in temperature, hence no change in internal energy, U. dU is therefore 0, yet heat might still flow, so dQ isn't zero.

@RalishGaming 9 лет назад

Hey! Just wanted to point out something. During your isothermal description you rearranged the formula wrong, should be U=Q-W. Great vid though! Helped out alot :)

@nurulshafiqah1 8 лет назад

ohh thanks..im confuse for a little bit because of that while watching this

@kelvintan4674 7 лет назад

U=Q+W is true because he said W= work done "on" gas... For U=Q-W, W= work done "by" the gas... its just a matter of how u want W to be represented by...😉

@abhijitsingh07 6 лет назад

But first law of thermodynamic States that dQ=W+dU , so how dU=W in an adiabatic process

@dingleberrys232 6 лет назад

Do you mean why is it not dU=-W? Because I do not understand why it is not a negative W value.

@leftenanalim 5 лет назад

Because in an adiabatic process, heat change is 0, hence dq=0. Therefore 0=dU+W W=-dU

@arunapothula5577 4 года назад

water temp outside container increase or not

@iksiX99 4 года назад

yes, but very little, unless you have a small amount of it

@FieldsSam1 9 лет назад

Is the Q component heat transfer?

@billyroberts4316 8 лет назад

+The man himself yes, thermal energy

@hussienjaafar915 7 лет назад

but when we compressed the tank W is negative, the equation is delta U= Q-W ( W is in negative since work is done "on system") thus it becomes positive and not delta U= Q+W and since heat is flowing out so Q is negative , just wanted to clarify on delta U= Q-W , please reply

@secreswallowtail3372 6 лет назад

what about gamma ratio?

@carultch Год назад

The gamma ratio (some books call it k), is the ratio of specific heat capacities, that governs the reversible adiabatic process for an ideal gas. It is defined as gamma = cp/cv, as the ratio of constant pressure specific heat capacity, to constant volume specific heat capacity. It generally is a function of the shape of the gas molecule, such that 2-atom gasses like air and its components have gamma = 1.4, and single atom gasses like Argon, have gamma = 1.67. It has to do with the degrees of freedom in the gas molecule, that act as modes of energy storage.

@astha_yadav 2 года назад

Holy Jesus if only i searched and watched these in 11th grade 😭😭 Edit: wasted money on shi*ty tutions

@dheerajkumar-dq6qi 6 лет назад

why adiabatic curve is more steeper than isothermal curve ???

@carultch Год назад

Good question. The adiabatic curve is given by the relationship of P*V^k = constant, where k is the ratio of specific heat capacities, defined as k=cp/cv. Since the constant pressure specific heat is always greater than the constant volume specific heat, due to the gas expanding as it is heated under constant pressure, the value of k will always be greater than 1. Isothermal is given by P*V = constant (straight from the ideal gas law), while P*V^k = constant generates a steeper curve that governs the adiabatic reversible process. Why does P*V^k govern adiabatic processes? Here's the derivation. hyperphysics.phy-astr.gsu.edu/hbase/thermo/adiabc.html#c1

@charliedajoob2246 6 лет назад

LOOKIT. NOW LOOKIT. LOOKIT

@hh61 7 лет назад

Why is that at a constant volume no work can be done but at a constant pressure work can be done?

@ChrisCardozaisawesome 7 лет назад

Husam because at constant volume, change in volume is 0. the p🔺v term goes to 0 leaving u=q . so at constant volume, no matter what work you do, it wont affect your system.

@hh61 7 лет назад

Ohhhhhhh, for the life of me I was super confused about it, but yeah if the final and initial volume stays the same then that will be 0. Now it sounds so simple!