Specific heat and latent leat of fusion and vaporization | Chemistry | Khan Academy

[@jlpugh18]

I can't stress this enough, but these videos is the reason why I have a 95% in my science class.

[@rdlounge]

You are Mega amazing! Your videos are clear, concise, not fast, not slow, fluent and well structured. Your voice is soooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo perfect for a tired student! not soft, not loud ! Sal must be proud of you!! Please do more chemistry and physics videos !! Science needs people like you who are perfect speakers!!! Please !! say your name :)

[@LovelySmile55]

sounds like a sext

[@dr.nightmare1669]

meh LMAO

[@devantebrewster4468]

where did he get -17415?

[@hanusiddhanth7952]

HAH GAYYYYYYYYY

[@hanusiddhanth7952]

THREESOME MUCH ? ;)

[@ranjusoni7056]

I am totally amazed.I have been struggling to understand latent heat from last 15 days.I did not know how easy it is!!!!! All credit to YOU.

[@BabyGAIA99]

I like this tutor!!! Perfect speech! you should make more video!

[@neora8509]

holy sh*t my chemistry teacher (and school system) sucked. thanks to this video I was finally able to understand what all these things meant...

[@shauryaseam4597]

Now I can finally say yes when my dad asks: ARE YA WINNIN SON?

[@knutsnbolts2268]

I can't thank you enough. I finally got the concept of this. Qc+Qw=0 makes so much sense than the one my teacher taught us in school which is -[McCfe(Tf-Ti)]=MwSw(Tf-Ti) Now I can finally go through my homework smoothly without staring at my paper for hours and hours.

[@janieli]

Thank you, oh my god. Online classes are way too difficult if it weren't for you.

[@destinationbathroombeauty4206]

still in 2018 this is awesome. I watched a bunch but the clarity and conciseness really solidified this to me

[@nayantararanganatha6083]

THIS IS AMAZING!!! I have had this explained by my teacher and my tutor and you explained it in a way that filled in all the gaps!

[@chravuri]

it's 2024 and still helps students. Glad to have a class from you.

[@michaelclark4619]

WHat is this presenters name? I love his voice

[@pspfdghost]

+Michael Clark description at Khan Academy says that his name is David SantoPietro

[@nu.wa.n]

+Michael Clark some of his physics videos are like raps.

[@amritas2400]

I love that man

[@sheikhnouman6335]

Graph made it easy at the end. Nice One.

[@Airus777]

This was easy to understand, i never understood what 'Lv & Lf' was, and this video taught me, thanks again!

[@olmp-pl8dp]

after 8 years you cant imagine how much this video helped me thank you sir

[@whatwaq]

Perfect, much better than my physic class. Thank you!

[@tylera5598]

thank you sooo much, i missed last week of my physics class because of theatre, prom and like the eclipse and i came back and he had taught like, from momentum to thermal energy 😭. good lord.

[@ahmadazimi2151]

Do you just add all of those values at the end?

[@narottammadhabji5354]

It helps a lot Nice explanation 👌👌

[@alley5869]

In the last problem that you did are you suppose to add all of the Q values in the end? (oh wait I answered my own question you do! Thanks for the video!

[@sharonsolana]

I determined the same thing: add up all the Q's. But I am not 100% sure.

[@ximenaalmonte5870]

8:14 How did this final temperature come out?

[@vedbhobe9420]

powerful explanation clearing all the doubts......THE BEST!!!!

[@muneebanjum6268]

Very very veryyyy well explained...tysm😍

[@SciHeartJourney]

That was well explained and presented. Thank you! I'm curious about 1 thing. Let's say you boil 1 Kg of water at sea level. How much more energy does it take for that steam to to lift it 300 meters?

[@sibashaktidash2444]

MIND BLOWING filled in all the gaps and is understandable

[@Mellybeans0919]

Your videos make so much more sense!!

[@jiaqizhou5779]

HOLY SHITTTTTTT I NEED THIS TO BE MY PHYSICS TEACHER

[@pspfdghost]

+khanacademymedicine there is a tiny mistake at 14:19 - when David was calculating heat of vaporization (pink Q), he wrote 2,260,000 J/kgC -- there should be J/kg :) Greetings from KA Polish translation team ;)

[@forhandle111]

PSPFDGhost Yeah, you are correct there...

[@Mr-ep2qi]

so it is the sum total of all the energies at the end correct?

[@Dennis-er8xc]

simple and Straight

[@swayamjilla1790]

Superb explanation. Thanks

[@historylinetolinemarking]

Woww you are amazing..

[@rayz0rxxx]

wow i try to understand this specific thing in scholl for 1.5 yrs and still blur this video makes it looks very easy

[@kimspenda]

excellent!!! thank you

[@masol3726]

14:11 What unit would the integral of that graph represent?

[@angrypepecancer5205]

Many thanks. I have a physics exam tomorrow and this helps allot. Sub and like. This really clear video than the others.

[@yousifshahwan6330]

Thank you i had a physics exam and this helped

[@sharonsolana]

Great video! Thank you!

[@samantharosen7593]

for the last problem... you dont have to add all of the Qs together?

[@zooted.]

i dont want this guy to die

[@hoinhtrieu9637]

wao i really freaking easy to learn, i mean how you teaching, yea 💯 sir

[@abhiramupadhye9643]

You are the best physics teacher I have ever seen

[@unknown-mn9wo]

Tysm i have an exam tomorrow hopefully it goes well

[@rassimsimou1594]

Good

[@abigailbrand5836]

Super super helpful and clear!!! Thank you!!

[@luisdelgado7764]

Question, how much joules would it take to vaporize 1kg of water into water vapor, in 1 second.

[@sharonsolana]

That was a workout!

[@vatsaljain7029]

You are so good! Great Help! Thanks! 👍

[@suneethaproductions204]

at what age do people of your country learn this concept ???????????

[@suneethaproductions204]

in India we learn at 13 years old

[@stephbrdse]

In order to do the heat of vaporization/fusion, will I always need to calculate the specific heat first?

[@manavgandhi7023]

thanks

[@sivashanmugam8734]

Thank you so much 🙏

[@riteshgoyal7560]

can we take specific heat of water as 4200J?and the video is very clear!!thanks

[@joetyler835]

in my school it uses 4200 just to make us easy to memorize it.. but to be more accurate use the definite specific heat

[@shellebelle9708]

I don't understand how you got 17415 and 167440. Can you please explain?

[@OBERON56]

Hershelle Wright he worked it out with out the change in temp for both

[@vaishaliohri8808]

The videos r great but just one thing it should be 2 litres of water not 2kg of water

[@avijaanroychoudhury3021]

excellent 👍👍👍👍

[@unknown-mn9wo]

Why is the specific heat for water different because in my book it says 4180 does the scale temperature effects it?

[@fraznofire2508]

5:51 wtf how did you get those numbers

[@PK-qs5xw]

He just multiplied the equation above he multiplied q for the object with the mass times specific and change in time and adds q mass times specific heat and change in time

[@rainheaven904]

Thanks so much :D

[@happychunky6845]

brilliant video

[@lenapetrovic7094]

But aren't you supposed to use Kelvin? Great Videos by the way, your channel has given me an A so many times I lost count :)

[@forhandle111]

Lena Petrović The units are going to be canceled out because you will change the C in McAT like the R in PV = nRT. Kelvins will cancel out with C-Kelvin and Celcius will cancel out with C-Celcius. But I also think Kelvin is more international and makes more sense.

[@suhaasnarayan7258]

Do you not need to convert kilograms to grams?

[@danielhara9633]

I really like this guy

[@gregorypatterson8276]

what about steam to liquid?

[@ansahsiddiqui1384]

thank u sooooo much

[@IZZY3201]

Thank you for making this video 👍👍

[@jacobvandijk6525]

After 3:41 : the copper and the water DO NOT contain heat! They contain internal energy. Heat is the FLOW of energy! Very confusing use of physical concepts.

[@abdelstar3999]

perfect i understood . thank you very much

[@sammocammo8729]

What happens when you have positive specific heats and negatives? eg. above freezing specific heat is 3.6 and below freezing is 1.88 . how do I factor this in? and also when the freezing point is not at 0? say the freezing point of apples is -2.3 degrees celcius

[@migron4662]

I can't understand Your question is Half

[@melho.martinez761]

Damnnn. A1. Thanks! Hope I remember this for my quizzzz. ;(

[@andrewlau7521]

How did the quiz go

[@woradonworadee1098]

Thanks for Thai sub.

[@MsShubhammalik]

I think he meant the amount of heat require to turn solid into liquid for heat of fusion, not the other way round

[@edsoncastillo96]

how you do it when your water is already at 100 c? Calculate the heat change in calories for vaporization of 30.0 g of water at 100 ∘C

[@azrielshacham6829]

The specific heat (Yellow) is 2010 J/Kg C or 2010 KJ/Kg C

[@angrypepecancer5205]

should Qsubc should be negative?

[@forhandle111]

angry pepe cancer Yes and no. The Qsubc is a unknown so it can be positive(like water) or negative (like copper) but, in this example, it is negative.

[@acevictory3587]

Thanks m8

[@vanessaescalera4117]

where did the -17415 come from?

[@ruzicamarosevic7763]

Cool video, but you have been writing Temperature that is in K(KELVIN) in Celsius degrees... If you already do that, at least write theta not T

[@Hansel.c]

Excellente

[@carterfoggin4548]

Online school ???

[@anonnona6940]

Shouldn't it be 90-Tf in the first example as Tf is definitely < 90°C. Pls someone tell me.

[@princessbloomofdomino950]

No the ice's cooling down so the temperature (Tf) drops by 90 degrees (Ti)

[@jayg9607]

But I'm still confused as to what's the difference between latent heat and specific latent heat

[@arhamraza9505]

Specific heat is the amount of heat required to raise the temperature of a substance a certain amount. Latent heat is the amount of heat released during a change of state

[@anonnona6940]

latent heat is just amount to get liquid to vapour(varies from mass to mass, more mass=more latent heat) but specific latent heat is mass specific and it is like heat required to get it to steam per unit mass. = heat required/mass

[@phoenixhartmann7121]

How far does one need to scroll down to find a comment about the 'latent leat' in the title?

[@aarohanrai26]

We've learnt that the specific heat capacity of water=4200J/kg°c

[@masol3726]

the earth is an oblait spheroid

[@RaviRaj-xt4vg]

Nic voice

[@misterhasnainraza]

Amazing explanation

[@Daniel-dl6cu]

I feel like I've been lied to by teachers because I was taught that water has a specifric heat of 4.186 but everyone keeps writing it without the decimal point.So of course I get a completely different answer. What is the truth?

[@karenhouley3626]

4.186 is the specific heat of water in J/g⁰C, but this equation uses J/kg⁰C, so if you convert it, it equals 4186J/kg⁰C

[@luialejo8972]

193.5 wat is that number

[@Sa.Fa12]

Isn’t it 4.184

[@dzdzdz_]

omg i love you :(

[@ahaan-thakker9142]

Very helpful

[@VirtualWorld-wv2um]

Video at 2x ... Like he's rapping😂

[@akhilvenkat9434]

he almost went aggressive at the end

[@1Shoda]

I love u so much

[@Anonymous-wo7ce]

Man, it literally takes around 25 million joules to heat an ice to steam

[@stacersrod]

the specific heat of water is NOT 4184 J it's 4.184J.

[@kylemumma1290]

its 4.184 J/gC, since theres 1000g in a kg its 4184 J/kgC

[@stacersrod]

your units do not match. there should be less kg than g. regardless, it’s 4.184 J/g°C. the unit is in grams and if it were to be kilograms the decimal would be even smaller.

[@praneethaluru2601]

awesome

[@davidhou4256]

Isn't the specific Heat for Water is 4.184J/g Celsius ? I'm so confused!

[@tbssen36]

David Hou Late reply, but you are correct. The specific heat of water is 4.184 J/g, but he converted it to kJ/g thus multiplied 4.184 by 1000 (because 1 kJ = 1000 J.)

[@HARSHVARDHAN-im2hb]

Wow

[@ncbwztcw]

And we are losing the polar ice caps at what speed? 😭