Specific heat, heat of fusion and vaporization example | Chemistry | Khan Academy

[@finpin2622]

I couldn't understand this at all in chemistry but now I'm like "oh, yeah, that makes sense" THE CHART HELPS EVERYTHING

[@debasissahu5261]

Sal, your voice makes everything seem so easy to me . Thanks!!!!

[@tictock700]

I know this video is quite old, but thank you so much!! For some reason teachers love to give very vague lessons. This really helps clear up all the little things!!

[@Reydriel]

Bangblockbap That's usually because they don't actually know what they're talking about :P

[@digedanken]

The voice, turning complexity into simplicity and great sense of humour, made me watch this video from the start to the end! Thank you Sr.

[@ryanbrunner5622]

First line: "a couple of video agos we learned.." lol i still love your videos and appreciate your attempt to give students an intuitive insight on the subject matter

[@noellepluschau13]

I wasn't in class when this topic was taught, and I didn't do well on the test. I have my midterm tomorrow so I was looking up videos to teach me and know it all comes to me so easily! Thank you Kahn Academy!

[@abbienovoaruiz6986]

7:18 , did he change or make a mistake on the number of *heat of fusion* that is *(333.55)* writing it he like 335.55? Because sins that its totally diferent the results. Please tell me, I am confused...!

[@ChrisThurberDusseldorfer]

You're amazing. Again, a fraction of a period of Chem class and I learned so much more...

[@thabangmakgenepye447]

Am watching in 2018 and thnx for that mistake it really help to show if i was following or not

[@ThatGuy-hu9mt]

At ~9:50, why does he not go through heat of vaporization? Also is the value of Hf 333.55 or 335.55?

[@falls0ft]

@Maishir Yes, the Celsius and the Kelvin scale are essentially the same, except 0K is -273.15*C so the kelvin scale starts at a lower point but the amount of heat you need to add to increase by 1*C or 1K is the same - (or for liquid water, 4J) inb4 confusing

[@devaneyann4970]

Why is my chem teacher getting paid more than Sal?

[@ERboss-87]

he isnt

[@rowandas952]

@@ERboss-87 wasnt*

[@Manigo1743]

How do you know how much any of them gets paid?

[@mondo1318]

I cannot thank you enough for all your videos. I have used them for Physiology, Chemistry, Microbiology, & Physics. Always so helpful, clear, short and sweet! You are awesome!

[@xtradizy]

Thanks so much, got me to understand heating curves more and what happens when you add in a certain amount of energy into the system. Homework accomplished :)

[@ThePraveenRakki]

Thank you so much,,, I understood this so fast!!

[@PramodKarthikeyan]

Thank you this was extremely helpful 😀

[@WerewolfSlayer91]

Man this guy has MASTER degree in EVERY F***** subject, with technical education.

[@bskbsk1032]

Thank you very much. This topic was so dry for me, but now it is interesting.

[@desidol22]

ahhh! Thanks so much! i finally understood this stuff :]

[@dcf8978]

THANK YOU SO MUCH!!!! This finally makes sense!

[@stickynena89]

YOU'RE THE MAN! THANK YOU SO MUCH

[@grawrzz13]

I love you sooo much!! my teacher is terrible at explaining things, but I can see clearly now xD THANK YOUUU!

[@Fungwabus117]

you are awesome these videos are logical and help me understand thanks bro

[@gumdrops27]

U just helped me understand something that took a week for me to even get enough interest to try in school. Come to my school and be a chemestry teacher please. :)

[@Sushiarushi]

@PaulRyan2k no its chemistry, it deals with the change in the specific heat of elements. We're learning about it now in AP chemistry.

[@tylermatthews6475]

I'm pretty sure he should have used moles instead of mass when using the equation regarding phase change (vaporization/melting). Because mass would not cancel delta H (KJ/mol), only moles will. and the equation for q is "q = n X delta H (vap) NOT "m X delta H". where n is moles not mass. He seems to be correct for heating up/cooling down a phase, using mass as the q. Because, that equation is "q= m X C X delta T". Does anyone agree? if so, like so they can see and update this video. source- "principles of chemistry text book 2nd edition".

[@jjjooorrrjjjooorrr]

Do you know everything!!!?? THANK YOU!!!!!!

[@narusasu7279]

Why didn't he work out the step from 100 degree water to 100 degree vapor? Since he worked out 0 degree ice to 0 degree water....

[@narusasu7279]

Oh wait haha I paused the vid when he made that mistake and didn't see that he corrected it after I unpaused the vid Nvm...😅

[@Bawnkeeh]

+naru sasu I made the exact same mistake even after I read your comment, haha.

[@zaynaba1854]

Omg I was having a crisis until I saw this comment and I kept watching. Haha, thanks

[@affinity_0912]

Love your videos and thank you😆😆

[@RAYz544]

THNX internet is the best tutor of the world :P

[@jtzab]

My college instructor couldn't explain this in this way at all. I could not understand the difference between specific heat and heat of fusion until I watched this video. Thanks! I don't know why teachers (seem to) think that the way to make a class a challenge is to explain things cryptically. I have to see the whole picture to get it. Learning deficiency or not, if teachers want to force the archaic model on people, they should not be teachers.

[@mattgreene8706]

Life sucks when teachers can't empathize.

[@Jeff-oh3de]

I got a chemistry test in 18 minutes on Heat Fusion Heat Flow H charts etc AHHHHHHH

[@Jeff-oh3de]

@@jacobdejesus2998 I have no notes I got a 77 on it

[@DeltaCJ]

it finally makes sense! thank youuuuuu sir!

[@curtpiazza1688]

I wish this was explained to me like this years ago! 😢 😊

[@RuchitaSahni]

COOL VID..gr8 job in educatin ppl~

[@majestic_science3424]

lol I love how he trolled us and left out the fucking biggest amount of energy in the formation of water vapor. then he's just like "oh uh looks like I forgot that little detail " lmao

[@Lady_Katie]

Your videos are awesome Sal! Thanks for saving the day again :)

[@Hellsconsort]

Yeay I was listening! I thought he forgot, then I thought it was just me, then he said \o/

[@JamesVestal-dz5qm]

Lattice structure is introduced while describing enthalpy of fusion of h2o without being described.

[@tripleAAA560]

final exams next week and Thank God for youtube teachers

[@VinylUnboxings]

Did 333.55 switch to 335.55 by mistake when you did the calculations?

[@relaxxx2607]

Thank you so much Sal this video was very very helpful. Have a test tomorrow on this and thanks to you I feel much more prepared.

[@RarwAshleyPersonal]

Thank you sir, for helping me with my homework.

[@RusticRiceball]

Thanks so much for this!

[@AhWing89]

thanks for the info.

[@TheJamaicanQueeny]

Error: You used two different figures for heat of vaporization! 335.55 and 333.55

[@darleenmarieramos]

Sal you said that the Hf was 333.55, when you did the problem you multiplied it as 335.55*200 and it gave me a wrong number when I did it with the initial Hf you gave (333.55).

[@hassanawan5920]

Hi I need your help about thermodynamics .

[@ChetanSharma-oy4ge]

we memorise these values or they already given in the question? specific heat values ? (solid liquid and vapor )

[@Tylorgirl22]

This was very helpful, thank you

[@v3NoMSteaLth]

@khanacademy I have to be honest, you are the reason i'm passing physics.Thank you.

[@CaptainGanu]

According to me its chemistry

[@e.b.2525]

Thanks a million! Best explanation yet!

[@hassanawan5920]

Hi

[@random3148]

Thank you so much! Now I won't fail my test!

[@sciencenerd7639]

thank you

[@bb33nnii]

god bless the youtube teachers

[@kkmatt]

it isn't the same. for the equations, you are only interested in the CHANGE in temperature. The DIFFERENCE from -10 degrees C to 0 degrees C is the same as 263.15 K to 273.15 K: 10 degrees.

[@Representt]

@Violetavrie for specific heat yes

[@caswelmaluleke7445]

1)do i have to go the very same procedure if the graph starts at the horizontal axis? 2)there is no alternative method of doing it,for instance dpoing it in one line by taking out the common factor which is the mass?

[@annarudberg5537]

Super helpful

[@tigercece11]

Thank you so much. I wish kahn academy could be my teacher.

[@johnperalessyahoo]

very, very, very! helpful.

[@FourEyedLadyOriginal]

Well done!

[@allylack5508]

When I learned this in class, for the segments that the phase changes take place. So for segment B and D, where melting and vaporization take place. The formula I was given was the number of moles x delta H fusion, and moles x delta H vap. Is this still the same???? I am confused!

[@Ali-tf5oe]

So actually you told that the heat of fusion is the amount of heat required to take away yo fuse 100°C ice into 100°C water, it's not 100°C, it's 0°C ice to 0°C water... Yes and you're the best teacher I've ever had🛐

[@obyuzoka]

Nice

[@Hollyglitter]

should he have used Kg? as thats the SI unit?

[@Bawnkeeh]

+Holly O'Riordan grams and Kg are all SI units. It doesn't matter which one you use. I guess it depends on what your professor wants too. But actually most of the time grams are used rather than Kg or mg, etc.

[@tomalley3585]

in chemistry you use grams, I hate it. in physics you use kilograms. chem is gms (grams, metres, seconds) and physics, my favourite, is kms heheh

[@SwolePatrol_1969]

@Sushiarushi That's weird, because in my course it's in my Physics, not my Chemistry book. Oh well :P

[@tharpoe]

Because Latent Heat (Heat of Fusion and Heat of Vaporisation) occurs after each change in phase and the formula is Q(Energy)= Heat of Fusion * Mass

[@jimmyrussin2992]

Thank you so much this helped a lot!

[@rebelchem]

@caribbeansuntrue all of his constants are in grams, so no problem. He does get the definition of fusion backwards though. Fine video mostly. Easy to understand when you can rewind and play again and again...

[@Gale953]

Thank you!

[@RuchitaSahni]

@Violetavrie ya- 373 K = 100 degrees C :)

[@zypykirubi1140]

Thanks A LOT!!!!!

[@rapharenthlei]

Thank you so much Mr.Khan :)

[@niccidell]

I just adore you

[@surdana]

Why does the anion have no affect on the color of a flame in the flame test?

[@elsimple15]

thanks for your comment, i was wondering how come he didn't convert to K ... but i now noticed the difference is the same ;)

[@edwardarakelyan9807]

Thanks khan, I hope my comment is read by uni physic lecturers. you all have to learn to teach from Khan...(not all but most of the lecturers)

[@jomsoo9142]

I get this video, but it would be better if conversions are done to show that the measurements are actually canceling out before arriving to the final answer. And I notice that the heat of fusion value used midway in the video was incorrect because at the start of the video, what was written is 333.55 J/g, but what was used is 335.55 J/g.

[@troller123able]

Thanks man!! :)

[@SirMaarten314]

I have a question probably a stupid one but nevertheless here it is: Once the ice is heated enough it turns into a liquid shouldn't we change metric system? after all aren't liquids expressed in Liters?

[@ThewickedLol]

OMG thank you! :)

[@MattS6993]

@1aliceinchains I'm doing the course this year :)

[@codemonkey732]

Damn, I need to stop watching these to do chemistry homework. My chemistry class is stopping me from learning chemistry. How ironic.

[@rowandas952]

9 years ago lmao

[@cerebrum1270]

great video.

[@katiej2489]

October 2019 🙋🏻

[@ranjanatiwari9808]

Very good

[@RsGhost1]

@apasionadagatinha Because it's the temperature change, 0 - - 10 = 10

[@Violetavrie]

So... Kelvin and Celsius are interchangeable?

[@Pugpono]

Sal! Thank you! The visualization really helps to see what q = mCs∆T really is and what it's doing. Something clicked, thank you!

[@remmytortilla]

I'm confused, where did he get the 335.55 at 7:22

[@aanon4019]

He screwed up number of threes v number of fives in the heat of fusion of water

[@prabhanshukatiyar4635]

thats a constant value for specific heat of vaporisation

[@ToastMasterGuy]

@SirMaarten314 No question is a stupid one. ;-) You would not make this conversion because grams measures weight while mL an L measures volume, two completely different things. Also grams is metric already XP.

[@doomkun]

I think what you're referring to is a bose einstein condensate.

[@prabhanshukatiyar4635]

thnx bro

[@mattgreene8706]

If heat does not rise while undergoing fusion or fission, what is happening to the atoms and molecules when the energy is being applied to the system? If they are not vibrating more and creating more heat, how is the energy affecting the atoms?

[@Mohammad_lyallpuri]

10:53 / 1

[@cachdoan]

And then I only have 3 minutes to do this problem in reality... That's about how much time our instructor gave us to solve this type of problem. Time is up, and finger is crossed.

[@skll2081]

I don’t even know if my chem professor knows how to do this, he just sends these videos.

[@chennis134]

It takes so much energy to go from 0 degree ice to 0 degree water and 100 degree water to 100 degree vapor

[@Nyuum]

Q(J)= MassxSpecific heat capacityx (difference in temp)

[@HAWXLEADER]

they both vchange by 1 degree with the same amount of energy... they are the same but with 237.15 diference! in this case we don't care what it is we only care it jumps by 1 degree with a certain amount off energy! you are welcome!