Enthalpy: Crash Course Chemistry #18
ฝัง
- เผยแพร่เมื่อ 23 พ.ค. 2024
- Energy is like the bestest best friend ever and yet, most of the time we take it for granted. Hank feels bad for our friend and wants us to learn more about it so that we can understand what it's trying to tell us - like that any bond between two atoms contains energy. How much energy? That's not the simplest question to answer, but today Hank will answer it (kinda), by teaching us about a nifty little thing called enthalpy.
If you are paying attention to this episode you'll learn what the state function is, and how it varies from a path-dependent function; why enthalpy change is different from heat; that bonds are energy and to form and break them they release and absorb heat to and from their environment. You'll get the quickest introduction to calorimetry ever (more on that in upcoming episodes) and learn the power of Hess's Law and how to use Germain Hess's concept of the standard enthalpy of formation to calculate exactly how much heat is produced by any chemical reaction.
Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App!
Download it here for Apple Devices: apple.co/3d4eyZo
Download it here for Android Devices: bit.ly/2SrDulJ
--
Table of Contents
State Function 1:50
Path-Dependent Function 1:15
Enthalpy 2:58
Bonds are Energy 5:10
Colorimetry 5:36
Hess' Law 6:19
Standard Enthalpy of Formation 7:24
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Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App!
Download it here for Apple Devices: apple.co/3d4eyZo
Download it here for Android Devices: bit.ly/2SrDulJ
"Haiku's are easy,
But sometimes they don't make sense,
Refrigerator."
Awesome shirt.
i love how he says "if you were paying attention, you learned" knowing full well half of us zoned out and have to re watch it
These videos aren't the reason I'm passing chemistry. They're the reason I have an A in chemistry.
These videos are the reason I'm passing chemistry....And the cute redhead that sits in the second row.
I've got the same problem in another class. Cute red heads, man....
In my country A=Achieved and is the equivalent of passing
So when we say we passed, it means we got A :D
but how do you manage to get marks in numericals? I dont get marks in numericals.
what is your country dude?
Hank's Law:
'The number of Crash Course videos watched is directly proportional to the grades on the chemistry test"
Learned more in 11 minutes than in 2 hours in lecture for Gen Chem. Thank you
Yeah no Joke.
Daniela Hinchman ikr😂
really, i guess it will not be as, some of the deep things can be thought by your lecturers, only.
When you gotta teach yourself because of COVID-19
I love what you do!
But, this time a few errors slipped in, so let’s correct them:
Two things:
1st thing:
@7:22 you have a slide that lists the Standard Conditions:
T = 25 °C
C = 278.15 K
P = 1 atm = 103.25kPa
That is a slide with a couple of whoopsies, that mainly look like typos
in the temperature, it is split on two lines and 273.15+25=298.15, not 278.15
in the pressure 1 atm = 101.325kPa not 103.25kPa
What I think the slide should have said is:
T = 25 °C = 298.15 K
P = 101.325kPa
Sidenote: there are several standard conditions, the one referred to in this video is SATP - Standard Ambient Temperature and Pressure, but I can see how this distinction is unimportant for this video.
2nd thing:
@10:16 Hank says: “All that energy locked away in chemical bonds and then released as heat to my aching frozen fingers.”
I have to take issue with this phrasing, as it perpetuates a common misconception, that energy is stored in bonds; thus, breaking them releases that energy. That last part is not the case:
Breaking bonds require energy.
Forming bonds releases energy.
If you look at the reaction equation @9:22 4Fe+3O2->2Fe2O3 you can see a net gain of bonds. While all bonds are certainly not created equal, the heat to Hank’s hands comes from the formation of bonds between iron and oxygen, not from the breaking of dioxygen bonds or metallic iron bonds, unfortunately his sentence implies otherwise.
I am aware this video is over 4 years old by now, but I still hope it will make it to the CrashCourse people. If you are not such a person, and still read all this, please like to increase the small chance that it gets seen.
*equal
Kelvin*
Pressure*
@Finn Molloy 298.15*
Shut up nerd
well...midterm tomorrow. all i can do at this point is ask for prayers, friends.
Did you pass?
@@kombat4135 I was about to ask the same question!
Am I late to ask?
@@malshammarii2000 yeah probably
who else is cramming before assessments?
you have no idea
AP chem test tomorrow
haha SAME
Dude me too and I'm a sophomore kill me
yupppp... 04:16 AM here.
Enthalpy @ 3:10
Calorimetry @ 5:30
Hess's Law @ 7:20 and 8:20 and 9:15
Thank you!
Thank you!
Thank you!
fuckin fight me Hank green I'm gonna grow up and find the volume of the goddamn ocean
You want a graduated cylinder for that or what?
+Christopher OBrien if it can be supplied, then yes please.
+adam c i bet you 1 million you wont find it in the next 10 years
+adam c NO EXTRAPOLATING
+adam c The volume of the ocean is ~1.332 billion cubic kilometers.
I had 4 lectures on this stuff, 2 seminar sittings and spend about 4h trying to understand this with my notes and textbooks. And then i watched a 10 minute video and am wondering why everyone explains this so complicated in the books and lecturs! Honestly, if I pass this exam tomorrow, its only because of crash course!
It is so satisfying to actually understand things!!!!
after watching this i feel like youtube is gonna help me through my university studies.
very helpful and it gave me a motivational boost of interest to keep on studying! thanks!
+Nihar Baijal Yeah. MIT OpenCourseWare is a great resource.
I feel pity about me that you are learning this in university but I'm learning this in highschool and confusing about enthalpy and losing my holidays.
12123 yurana just first year biology, so i don't even have very advanced chemistry ;)
***** I'm G12 and learning this in Japan's international school with Ontario course, which I'm not native but doing this incomprehensible thingy.
I'm in BIO105 and this is really helpful.
Hank I have never loved your nerdy face more than I do right now. I've been cramming for this Gen Chem test all night and you have probably just saved me from myself. I owe you buddy.
If I discover a scientific law I might just name it Hanks law.
Yeah, That would be original
@Rowan Brown WELL I WOULD NAME IT HANK GREEN'S LAW
Green's law would confuse ppl
I wish that one day some brilliant student who learned Chemistry through your lessons would discover a new law and name it after you. You really deserve it Hank..... U must be a genius for explaining us chemistry through 10 min videos which our stupid teachers couldn't do in hour long regular lessons
and the newly discovered element with atomic no.119 has been named Hankanium
+Mitali Patil no element with atomic number 119 has been discovered as of today
+Mitali Patil This element probably won't be discovered, it was a miracle enough to get 118.
Most likely, the next element that is stable is 132
??? i require evidence of such
??
+SwenglishGamer it was a joke
I'm sad that there weren't any dollar bills flying out of the banana stand. There's always money in the banana stand.
Please do some physics crash courses!!! I really need it 🙏
there are also physics videos.
Vasanth Kinda trash tho
Shining to the rescue
I mean shini
PBS space time is pretty great
I just discovered this channel, and this is probably the best lecturing i have ever seen. I think this is how lessons should look like even on colleges and universities. The fun stuff is what we need at classes, the rest we can read in books. Enjoyed it and looking forward to exploring the rest of the channel.
I wish so much that John Green would be my AP chemistry teacher
This video features Hank Green, John's brother.
+Breezy Starmeadow Ah
Same! I take AP Chemistry too and my teacher just doesn't know how to explain things well.
+GlamGoddes101 same here.
User I think you mean Hank...
Since my final is this week, Enthalpy is a friend I am going to try very, very hard to understand...
This account is like a gift from the heavens. I honestly downloaded the all their videos, whether or not i have the course or not. It's fun to watch and at the same time very very productive
6:48 , when you were like "not bad", i couldn't help but laugh at that part.
I love the arrested development reference. And I love the video. This whole thing is just really good. Especially as a recap for finals. Thx guys
Chemistry = Confusing fun stuff. :)
Gaa! Really confusing because of the math - the rest of it REALLY is fun though, right? to bad I'l failing the class :(
You'll be fine :) The math is easy depending on the way you think of it
She might fail English though...
Nathan Gjelsness lol
***** ...right
Wow this is ridiculous.
I am a high school student and I have a few friends who study chemistry (and I don’t I study physics), I remember that a few weeks ago they had a test coming up, we were in a classroom, and they were on the board writing equations. I had no idea what they were doing, but now I do they did this calculations this is ridiculous with a few episodes of crash course chemistry I understand in chemistry about as much as a few friends of mine understand from studying it in school for a year and a half.
Thank you Hank I’m so much smarter because of you.
Crash Course coming in clutch during finals season! Thanks Hank!
Thank you for explaining the correlation between delta H and q. I didn't understand it from my textbook and I needed it for homework. Hank, if you are reading this, you and your writers are amazing and thank you!!!!!
Hank: Explaining stuff about enthalpy
Me: Trying to read this T-shirt
XD
Thank you, thank you. What my instructor could not communicate in two hour long lectures, you made intuitive in less than fifteen minutes. Bravo sir.
...and I thought I knew everything (or just enough) about enthalpy and thermochemistry. I'm surprised how many new things I actually learned from this.
Great vid as always!
I swear....learned more stuff in 10 mins than 100 hours in lectures!!! Hats off to #crashcourse (y) !!! Ye are just freakin'
awesome!!
Haikus are easy
But sometimes they don't make sense
Refrigerator
Your haiku makes sense
But don't joke about a fridge
I prefer freezers
Haikus are quite rigged
They never make sense silly
Dab on em haters
Doctor cardio Fix the first line and then your haiku will work
@@doctorcardio1559
My experience?
Most Americans' haikus
Use the word "haiku".
@@aerobyrdable They usually are meant to not make sense
People generally don't understand them
the P R I U S has found me
dude you're the coolest scientist and best teacher I've ever listened to. Congrats and keep up the good job!!
Hank, I wanted to let you know that you and John here at CrashCourse have helped me. With your abundance of (long) videos, I'm not only learning by listening in at random parts, but your voices help calm my anxiety and it's basically like listening to calming music for me. Thank you! xx
thank you!!! this is so useful for my AS Chemistry
OMG same!!
How is it going, senior?😏😏
Thank you so much for these videos. Totally helped me study for my AP chem exam!
Excellent Video . I was struggling with this enthalpy for over a couple of years
And you just make it clear in 11 minutes
Thankyou very much
You guys are incredible. I love your videos! Sometimes I struggle to find the playlist any given video is a part of. If the content blurb under the video had a link back to that playlist, I'd probably watch Crash Course more exclusively.
loved the arrested development reference
+jesninee I thought that they were "a huge mistake".
+James Greydanus I'm sorry about that...
+James Greydanus There's always money in the banana stand!
Dom Z My brother actually saw the actor who plays George Bluth at star wars Force awakens opening and said that to him. xD
+James Greydanus your brother is a legend!
Shout out to Michael Bluth's Banana stand...
good
Why does this channel not have more views? These are all so amazing!!!
Thank you! 11 minutes watching this was so much more informative then my 3 hour lectures! Maybe we should all give you guys our tuition!
AP chemistry stresses me out
This video series allowed me to understand everything I missed or forgot in AP Chemistry back in high school three years back. Cool!
You're the only reason why I know what's going on in my chemistry class. Thanks so much!
The kelvin you used for the standard enthalpy is incorrect. Standard enthalpy is 298.15 K not 278.15 K.
You are hilarious and just brightened my day of studying! Loved the "Can I just go look at pictures of cats now?" !!
I'm so happy that you're not afraid to use formulas in your videos. I'm gracious for the trust towards the audience.
Really helpful. You make me feel more interested to study chemistry. Thank you very much!
Can you please make a video where you explain all this as if you were talking to a five year old?
Asking for a friend.
Seconded
Watched this in AP Chem today, aw yeah.
I just want to thank you and the crash course team for making my high school chemistry tests not that fearsome.
I love all these videos, the science I learn in school only focuses on the basic rules and doesn't explain why the formulas work and it's frustrating. With Crash Course, I can grasp it better because it's not just a bunch of numbers, letters, and symbols. Also, I have that shirt, and my English teachers love when I wear it.
"can I just go look at pictures of cats now??.,/,./"
Hahahaha Hank knows his audience
All I could think of when he said "Better living through chemistry" was "Better living with Collins and Collins"
This video is epic.I learned a lot.This is the reason I got an A+ in chem.Loved it.Thanks bro
Ive started watching the biology course today and I'm 15 videos (lectures) in. Awesome videos, awesome course and sufficient information provided. Thank you crashcourse.
I needed this for AP chem...ugh.
+Bob John i feel you bruh, i took the ap chem trap 2 when i picked classes junior year. RIP
+Bob John really? the class is pretty easy for me
Thomas Bui It's different depending on the school. For a school like mine it's the hardest class you can take.
Yeah, it's like the bane of everyone's high school career. So, there's that. And I just kind of understand it because of my high arithmetic abilities. You know?
Thomas Bui No. At my school it's harder. Even the super smart people have a hard time.
"Today we shall answer it! Kinda!" Hank has the best quotes xD
Great episode. My physics professor never bothered to get the idea of enthalpy across which made thermodynamics harder to figure out. You cleared that mist that surrounded enthalpy. Thanks a lot.
that was almost a perfect summary of the second half of of my Thermo II class in Mechanical Engineering. well done sir
Thank you so much for putting the bluth banana stand
"IF i am reckless and insane"? Why is there an IF there...
This video has finally answered to me where the pV term in the equation for enthalpy went. Thanks!
This is by far the best explanation of enthalpy and state function. Better than textbooks!!!
At 7:24 seconds the temperature in kelvin is not correct. The video is really helpful. Keep up the good work!
ya... its
C = 273.16 kelvin
How'd you know that I was distracted and wanted to look at pictures of cats :O
This videos are wonderful Hank. It's a great reminder for a Chemistry major over the summer.
This video FINALLY helped me grasp the concept of enthalpy after about the 2nd or 3rd view. THANK YOU!!!
Theoretically, would placing the substance in a vacuum mean that the enthalpy of the substance would only be made up of its internal energy, as no energy is required to displace the air particles (VP)?
I am sure this has been said before somewhere in the comments but at 7:22 it should be 298.15K (not 278.15K).
Good catch! It is the difference between "standard conditions" and "standard ambient conditions." The former is 1 bar and 273.15 K and the latter is 1 atm and 298.15 K. Because he was using Standard Ambient Pressure, he needed to be consistent with his temperature.
Im so glad my chem teacher found this channel since watching these vids before class is now our homework
I use these videos more than my Chemistry textbook. Thank you so much.
AP Chem kids wya?
got a midterm in 4 hours im soo fucked
Ken Gonthier what upp I have a fckin test on Friday and I'm a sophomore kms
good luck tomorrow morning!!!
hey guys we made it
Got a test tomorrow lmaoo
Can you do some more high level chemistry videos (some relating to the AP chem curriculum) Thank You!
Cramming 2 minutes before the AP test. This is the epitome of life. Thank you school system.
Strange enough that I understand all the concepts you talk about in English rather than in my native language which would be German. Guess that's a clear sign of good quality work you're doing there!
You lost me after the banana stand
same -_- why do i have to go first in presenting for finals this is base level chemistry in highschool why are we doing this to children
Its good advice but can you slow down please, Would be appreciated,
That's the beauty of using the internet and vehicles like TH-cam for education; you can simply pause, replay, and review all of the material!
yeah. the point of these videos is to be fast. Just pause and play if it is inconvenient.
You can set videos to half speed on youtube.
Doctor Derpy I'm fine with the speed he talks but I wanted to see what he sounds like in half speed and dear god he sounds so drunk. Imagine Stephan Hawking drunk and his machine was drunk too.
Jack Xhemali This made me try the video at every speed possible and, my God, was it hilarious! He sounds the best fast though.
So I'm a ceramic artist an I typically fire with wood. I am taking all of these videos and using them to better understand why and how materials respond the way they do in such a volatile atmosphere. Keep up the good work.
In the final moments of my MCAT preparation, your videos are great concept reviews. Set the player to x2 speed and we have the quickest reviews yet.
Do Organic Chemistry!!!
Do a crash course physics series
You said it buddy!
Hey! Guess what? BAM instant physics Crash Course. Yeah you probably know this but they have a few episodes now.
thank god for youtube. 12 chapter exam wednesday dont have time to read the textbook to review. videos like this are nice to bring back everything fast.
I'm majoring in veterinary medicine for college and I have to take chemistry my first year. My professors are great teachers it's just I'm in south korea and I understand Korean like a middle schooler so these videos are really helpful for reviewing what I learned.
Arrested development, bluths banana stand
i thought that standard conditions was 298 kelvin which is 25 degrees , not 273 which is 0 degrees ???
Cara otima iniciativa, eu sempre quiz ter esses videos legendados pra poder mostrar aos meus amigos q nao entendem ingles muito bem, parabens.... vc ta fazendo um trabalho foda heheh
this is so much better than my class , thank you sir. accurate and well explained video.
I still hate chemistry
U need Tyler DeWitt
Well maybe Chemistry hates you... in Soviet Russia.
I like it but I suck at it (ㅜ.ㅜ)
Hey I hate chemistry as well
J S facts
Personally I think an element named after you is far more prestigious.
+Kyle Nichols Which can never happen again.
EDIT: Nevermind, if one was discovered in 2010, I guess there could be more.
+Ghost7856 2 in 2011/2012-ish and no fewer than FOUR are currently having their new name choices considered, to assigned later this year, after their (temporary/potential) existence being confirmed in 2015! :)
edition.cnn.com/2016/01/04/world/periodic-table-new-elements/
...then there's the quest for further discoveries beyond 119!
DrewKF
I see. That's neat...
You make me laugh and smile and love learning. Your videos are fantastic. Thank you for doing them.
bless! ur vids really help me out in bio and chem! we appreciate you😄
Dear CrashCourse people I think you made a mistake or 2 at 7:23. If I am not mistaken it should be: C= 298.15 K and P = 1 atm = 101.325 kPa. I know it is not a huge problem but maybe people get confused.
+Arthera lol just saw this too. its definitely 298.15
+Arthera He messed up the C but he rounds kPa if you look at his previous vids
Aurya T The kPa is wrong it should be 101,325. If you round that number off you wouldn't get 103,25.
haha im surprised you even caught that, cuz of how fast the video goes
Hello Crash Course team and everyone behind this awesome project, I just want to let you know that I've tried to contact on you for having permission to create portuguese subtitles for some episodes and since I got no response, I got a little ahead of myself and began to do it anyway. I want to apologize and want to let you people know that I'm trying to credit you everytime.
Well, that's what I wanted to say, if I'm doing anything wrong let me know and I'll take down the videos.
Best wishes, me
Dear crash course, I don't think you know how much help this is. THANK YOU SO MUCH FOR THESE VIDEOS
This has been really helpful with my AS preparations now l really understand enthalpy changes except that l need to really know about calculations of enthalpy change of hydration of an anhydrous salt using Hess law ,