Electrochemistry: Crash Course Chemistry #36

[@crashcourse]

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

[@quantuminfinity4260]

Cool!

[@sudeepjoseph69]

k

[@doctorwhocolour]

Is this designed for people who have tests in the morning?

[@mistree0007]

+ThisAccountIsNeverUsed that gave me chills :'( in 4 days is my test

[@kylecolwell8407]

actually watching this morning of

[@remleek8676]

Ryan Casey me right now

[@aliciakacharia5140]

Next period haha

[@FlamingFox12]

half an hour here

[@convict3]

I failed my exam... but i wouldn't have been able to say I tried my best without you!

[@superficial1557]

Hank saving me from year 12 chemistry >.>

[@chettymaanya9398]

Ikr.

[@MythicGirl2210]

Imagine college 😱

[@abishekraju4521]

i am. And i bet he is and so are you

[@10bit25]

I have chemistry and physics-electrochemistry and physics all apart.. lel PEC is the least thrilling by far lol. Chem and phys are fun lel

[@humairafarha3340]

Were you REALLY saved?

[@CptProtonicus]

Hi Hank! At 2:10 the 4 subscript is a typo on the Mn for the left side of the reaction; there should be no subscript. ThePlasticModeler pointed this out a month ago, but there's no annotation yet so I'll reiterate it. I love that you guys go back and correct mistakes with annotations; it gives these videos a peer review and correction process arguably superior to scientific journals!

[@aryanshetty6536]

Hank green!! The best Chemistry teacher ever. I had completely lost interest in chemistry...... But then , here comes Hank Green in crash course chemistry and TADA i love Chemistry again. All thanks to the great Hank Green. I love CrashCourse Chemistry and Vlogbrothers Hank is just too cool!!.

[@javianbrown8627]

I wish teachers could animate real life like this. it would make things so much easier

[@AdityaBytha]

Exactly!

[@humairafarha3340]

The point he says "if you were listening...." I break down. Was I really listening?

[@jesseinfinite]

I'd have prefered more formulae in the crash course... But yes he speaks at a perfect pace.

[@SanjayGupta-hx9ri]

I love crash course! If only there were a CRASH COURSE PHYSICS!

[@FROPDESAI]

Sanjay Gupta WHY DON'T THEY DO THIS?! CrashCourse , PHYSICS MIGHT BE THE MOST DEMANDED SERIES! Please, do this.

[@FROPDESAI]

John Doe Thank you. Also, your name matches the default name of the character in games by Kairosoft.

[@FROPDESAI]

***** Thank you.

[@skyloftian8241]

Sanjay Gupta Crash Course Physics is a goal on their patreon www.patreon.com/crashcourse

[@dbzaddict444]

+Tanishq Desai its just a typical no-identity name hahahahah although Kairosoft games are good fun.

[@chinecobisag5522]

I love how he genuinely laughs at his stupidity at 3:03🤣

[@blue.nostalgia]

that moment when you don't pay attention in class and came here hoping that maybe you could digest everything in minutes... yeah i'm good, just gon get some tissues and start creating excuses for my failures later

[@berrywarmer11]

This is the Chemistry that your teacher wants to teach but can't afford to due to having to adhere to a curriculum. My own class is mostly process, math and rote-learning based, using this "Crash Course" as a way to get a solid CONCEPT based understanding. Chemistry is often very boring material if you look at it in your textbook, but Crash Course makes it come alive. The effort they put in is clear, and the devotion they have to the subject is real. Don't complain about them for not delving into equations enough: there is too much boring material already out there if you wanted it; read your textbook if you want problems and formulae.

[@maryamkhan7027]

People: he talks too fast! Me: watches in 1.5×

[@geethajeylingam1460]

There is a mistake here , in galvanic cell anode is negative where the electrons are produced from, and cathode is positive. In electrolytic cells, the other way around, cathode is negative and the anode is positive

[@MattisProbably]

00:42 and onwards was the most amazing and adorable thing I have ever seen on KZbin.

[@ssc396]

School : Time for some EXAMS....😈 Crash course : Time to save some life

[@EmilyB42]

To be honest I'm watching this video because I just got hired as an engineer at a flow cell battery research company and I need a bit of a refresher. So thanks

[@ChuuliviaHye]

Last unit test for my ap chemistry class yesssss i need this class to be over omfg

[@ruchi4965]

Same for me! Out last test is electrochem tomorrow

[@qtentertainment3845]

+Sapphire Kawashima Saaame

[@jacobroberts8931]

fml let this class end I have 4 more weeks

[@BowlOfCuriosity]

is it weird that theres a love and hate relationship for the feel of the class ._. MAY WE SURVIVE MAY 2 #letthecramminggamebegin

[@ChuuliviaHye]

BowlOfCuriosity im so stressed for ap tests omggggggggg 5 tests q.q

[@JinTheSlim]

Excuse me, I have to pick up the blown off pieces of my head...

[@haninnasirabdullah1462]

I know right?!

[@selly-123-w6q]

Hhahahhahhah

[@alexapeters9786]

Error in 1:53... Manganese(IV)oxide is MnO2 like shown in the half reactions, and not Mn4O2 like is shown in initial ecuation.

[@JohnSmith-gl8qq]

Alexa Peters Ayeee i was about to comment that. (And speaking of typos, *equation)

[@PikachuTries]

Was looking for this comment

[@bayleaf4003]

This show really helps in my AP Chemistry class!!! Thank you to all who make these shows they help more than you know!!!!

[@SuperPrettyCOLORS]

had to drop AP chem. I didn't watch enough of these videos.

[@swde4793]

Wrong, In batteries only! Positive terminal is called the "Cathode" and the Negative terminal is the "Anode". I repeat Batteries Only.

[@nevereveranything]

If by batteries you mean a galvanic cell than yes. In an electrolytic cell the charges of the cathode and anode are switched because current is moving in the opposite direction (like recharging a battery).

[@RubyChiang]

Andrew Karpinen so only in batteries is the cathode negative and the anode positive? I was confused because it showed the opposite, thinking; "Isn't the cathode positive and anode is negative?"

[@raishams4032]

Andrew Karpinen You are correct! My textbook says the same!

[@raishams4032]

Oh wait, the diagram at 3:54 shows this, oops

[@swde4793]

Ruby Chiang Answering your Q. No, A battery ( any typical battery, i.e. NOT a capacitor) chemically able to create a Voltage difference between its internal structures end to end Will provide EMF (Electro Motive Force) in the following path. ( Conventional electron therory always applies during discussion unless specified otherwise.) From the Negative - terminal ( internally ) with the EMF pointing --> + towards the positive terminal. (as im sure we all understand, I'm writing all this for sake of "clarity " here. ) Thus it is opposite any descrete components down the line, as they "Recive" their voltage at there "Anode" (+) and then deliver from there (-) "Cathode" . Using a Diode example, then power flows to the next component say an Capacitor at it's (+) "Anode". Are you seeing the pattern here? -+-+-+-+ as the Battery is two separate elements to its device. Hence the battery is a "Source" and sources thru it's Cathode out to an Anode in the circuit. You may notice I do NOT mention "Current" or "Charge" here as in general we use that terminology every day and thats ok. But not here because it's im portant to note that a battery does not provide electrons to a circuit. The free electrons used are in the wires and circuit itself. Ions work i side the battery and do work in the cell to provide EMF potential. Same as well for charge. If the last part confused you and made you curious then look up "Coulomb's law" and study and understand charge and you will then understand without question that a battery couldn't even stay together built from the strongest of materials. I hope thks answed your Q.'s simply put A battery ( using a car batt. As a common example) has a Positive (+) terminal that IS a "Cathode" and a Negative (-) terminal IS an "Anode". As I said before. Only, batteries. All other electronic components as usually desribed is true Positive (+) = Anode and the "Cathode" = (-) Negative.

[@Manabender]

0:42 Unbelievably giddy Hank is unbelievably giddy.

[@jarehelt]

crash course physics hank!! pleeaassee!

[@kirstenmedd6140]

When you labelled the battery where the anode is the positive terminal, and the cathode is the negative terminal, this is backwards to what I have learned. Oxidation, or the loss of electrons happens at the anode, while reduction, or the gain of electrons happens at the cathode. The cathode should be positive in a galvanic cell, or battery, whereas the anode should be negative. In an electrolytic cell they are opposite. In the battery described above, the zinc is oxidized in the anode (or negative terminal), and manganese (iv) oxide is reduced in the cathode (or positive terminal, using a graphite inert electrode). I think this video needs a slight edit to correct this.

[@muneebparacha3038]

This is simple cell where the anode and cathode depend on the electronegativity series

[@LindaengelustrupBlogspot]

It depends: In a galvaic element the anode is negative but in an elecrolysis an anode is positive. Remember: the rule "ANton the OX is scaRED of the CAT" still counts. (OXidation by the ANode and REDuction by the CATode) if I understand it somewhat correctly that is =)

[@kayleehyson136]

At least Hank actually takes the time to teach. AP Chemistry would be impossible for me without him!

[@irawinniewijaya2647]

I have chem quiz tomorrow and i'm watching this instead of studying my note and books lol

[@georgehanna8768]

WAIT WHAT! 2:06, Mn4O2 is not the same thing as MnO2! There is something seriously wrong here. According to the reaction both Mn4 and Zn are being oxidized which cant be. The MnO2 should be the correct reagent to make sense.

[@FROPDESAI]

George Hanna At 0:42, we have the cutest Hank green ever!

[@deepanshugajbhiye]

George Hanna the rxn for MnO2 is wrong! it takes 1 e to give MnO(OH). also many e 0 calculations are wrong but still great explanation

[@1713Fearless]

I truly thank you for saving my academic life.

[@xeztan]

Lydia Hayward you're beautiful

[@shefinmuhammad1130]

hi

[@DripisDaIdiot]

Why do everyone want to let her to like you guys...the more u guys say the less chance she likes you it’s just feels...............weird?

[@rahulchakraborty1779]

dude u make chemistry soooo interesting

[@MrEarthboundKing]

as·pect ra·tio noun 1. The ratio of two dimensions of something as considered from a specific direction, in particular. 2. Rhe dimensions of a display resolution. For example, a resolution of 800x600 has an aspect ratio of 4:3.

[@alexk7138]

These videos are timeless, and will be forever helpful to struggling ap chem students like me

[@TheDeedeenana]

At 4:00 everything just clicked and there I was screaming because I felt like I finally understood all the knowledge in the universe. Thank you.

[@kaybee1749]

3:01 When you have an AP chem test tomorrow morning and you're staying up to cram.

[@saadinhalf]

0:41 the chaotic energy of the universe just increased a little more there

[@Durfit]

These videos are beyond helpful. I really cannot thank you enough for them.

[@danryan2371]

At 2:49 they have it backwards. Positive is cathode and negative is the anode...

[@mocool05]

Awesome. Love the Xhibit animation! Epicness.

[@patriciocastillo2772]

The quality of the video is outstanding!! Everything is summaries and present in a clear and short way.

[@StarPurplePurpleStar]

In writing the Mn redox reaction (at 2:05) Mn (IV) oxide should be written as MnO2, not Mn4O2 as it's written now. Crash Course, do you do corrections? Sorry if I'm being picky, I love the videos!

[@AdvaitSaravade]

+LouisaStar you should be picky.

[@dcxs5896]

+LouisaStar Its a test u see

[@greatwhitesufi]

+LouisaStar Literally 3 seconds later they wrote it correctly, so no harm no foul.

[@courtsily]

+LouisaStar wouldn't it be written as M2O by that logic? Because there is twice as much Manganese as Oxide in M4O2

[@courtsily]

+Advait Saravade wouldn't it be written as M2O by that logic? Because there is twice as much Manganese as Oxide in M4O2

[@hallmorales]

According to my professor and my college chem book, the outer layer in alkaline batteries is actually zinc, while the inner layer is a paste of KOH with manganese oxide.

[@zarinawillows2347]

Is it just me or Hank looks super excited today. ☺️☺️

[@Nat-og5jd]

Never understood chemistry.Actually hated it.After watching this video I understood things which my teachers were never able to make me understand all those years.I have become a fan of chemistry.Respect to you and chemistry!!

[@RobCardIV]

yea !! the review notes at the end were perfect ! i could stop at every note and think back about what the subject was.

[@bhavinpatel4355]

love the videos, but at 1:52 the equation has Mn4O2 instead if MnO2, But keep making the videos, i love me some chemistry

[@jsinovercos]

Am I the only one that is excited upon every CrashCourse upload?

[@vwlz8637]

do Crash Course Maths, I NEED IT! NOW!

[@vivianaromeror2297]

In an electrolytic cell, the anode is positive while the cathode is negative. You might want to specify that since many people may become confused. In a Galvanic cell, the anode is negative and the cathode is positive.

[@KaleidoscopeFay]

i might actually pass my midterm now, thanks Hank

[@cheekyquin]

It will continue to frustrate me that my teachers dont even try to make chemistry interesting.. When i watch this i get super excited but the thought of chemclass gives me chills

[@frances277]

Wow this just summarized everything i’ve been trying to understand the past 2 days😭

[@hassandaniyal5540]

I had to give a test to enter the new school because of your videos i was able to successfuly pass the entry test. Thanks CC

[@tizakamanga2027]

In the Galvanic cell how are the two metals reacting without touching or being in contact when just connected by a wire

[@conorturk1757]

This is how you sound when you don't put periods in your paragraphs.

[@yvonnekavithe6247]

when he licked the battery lmao made my day

[@tmm246]

i am just bowing before my computer. i have a massive ap chem test tomorrow and oh my god thank you!!

[@kaii-lb]

9 years later and hank green still explains really well

[@purplenadz96]

Hank! Love the Crash Course Chemistry series! Please do one for physics it'd be really interesting and I think many people will watch :)

[@thatplane3865]

Feels like a rite of passage to be reviewing this morning of AP

[@TheBlackestKey]

I've watched a lot of crash course, and this is the first time that I need it to actually learn the concepts from class. AWESOME video I must say, very fast but I'll just have to pause it and take notes. Thank you very much Hank and the rest of the Crash Course staff.

[@jamesowings3681]

this is enjoyable to watch and its great for identifying what you aren't familiar with for review but I definitely don't recommend this for last minute studies but rather a small partial review after long length studying... that being said there is very little I can say otherwise... if you are taking AP or an exam.... you should most definitely be familiar with the structure of a Galvanic cell, know where the anodes and cathodes are in an equation, and figure out half reactions... much of what is said in this video is extra and shouldn't be taken into account as of "importance". Nonetheless, you cannot go wrong watching this video along with many others as you will indeed always understand Chemistry a great deal more with each reappearance of the subject you wish to learn and/or understand further.

[@mariosantos9928]

Writing CAPE Chemistry tomorrow, this is going to save my life lol (Caribbean Advanced Proficiency Examinations)

[@theopenmindedworld5906]

Same

[@zombieking411]

same

[@powderdescent]

Yo ho, yo ho aChemist’s life for me?

[@pigslayer275]

Voltage = Popularity... i have very low voltage

[@Sumeyy444]

Don't worry; my voltage is negative :P

[@windhurricane5736]

DamnJokster So you're infamous?

[@jiteanpandit7986]

Where live u

[@FreeSkillsStyle]

What a great way to unite art and sciences, you guys are awesome

[@tahnihinchley5337]

So I made my own galvanic cell and wanted to see what happened to the current when the molarity of the zinc sulphate was changed. The result was that when the molarity increased, the current decreased. I am unsure why this was the case. Can you please explain it for me? Thank you

[@BlazeCyndaquil]

At least by convention, yes. I certainly agree. What Hank has makes sense, but in a different way. I'm not sure what he was going for, but many Chemistry textbooks would disagree with it.

[@TheImaanNetwork]

For people like myself, who hate when people talk slow when explaining things, thank you and salute you. So concise and quick.

[@siddharthbhardwaj574]

Alkaline Battery best DESCRIBED..............LOVE CRASH COURSE

[@katie.scarlett]

this video came at perfect timing because this is what we're learning in APChem right now :)

[@emilyellisemilyellis]

hank's getting me through senior chem in 2023 xD i missed most of my classes on redox reactions and galvanic cells and now i'm doing a whole experiment on galvanic cells because my teacher said that titration's too difficult, kinda forgot that i'd have to study all the theory before i can even start

[@sflm9277]

I teach electrochemistry and avoid calling cathode and anode negative or positive, as it is opposite in galvanic and electrolytic cells. What is always correct is that at the cathode, reduction occurs and at the anode oxidation.

[@FirstRisingSouI]

How batteries work has always been a mystery to me, despite taking high school and college chemistry classes. This is the third time I've watched this episode, and I think I might be starting to get it. Let's see if I understand. The copper and zinc react with their solution, forming copper and zinc ions. These ions then react with each other, while the electrons form a current in the conductor. Have I got it right?

[@Benjen97]

hmm, ish. The copper and zinc ions don't react With each other directly. Sulfate ions moves through the salt bridge and Electrons move the opposite way through the conductor

[@FirstRisingSouI]

Okay, so it's a system of reactions, where everything reacts with what is next to it, the sulfate ions are conducted through the salt bridge, and the electrons are conducted through the metal.

[@Benjen97]

yes, and the Whole thing happens because one side is more reactive than the other. Ideally both the copper and zinc would like to be in an ionic state (so it has a full Electron Shell), but because zinc is more reactive than the copper, zinc will basically force feed the copper With it's excess Electron (Zn (s) --> Zn2+ + 2e-) So if you were to measure the zinc metal you would see that it loses weight, because Zn atoms are moving from its pure state to the ionic state in the ZnSO4 solution. You now have free floating Zn2+ ions in that solution. The excess Electrons will then move through the electrodes and the conductors to the other side. The copper sulfate solution (CuSO4) These excess Electrons gets picked up by the Cu2+ ions in the solution and more solid copper is formed (the copper electrode gains mass/weight) As the CuSO4 solution loses copper ions, there will be free SO4 2- ions floating about. These moves through the salt bridge and reacts with the free floating excess Zn2+ ions in the zinc sulfate solution. So bottom line, the zinc metal turns into zinc ions in a solution, the copper ions in the other solution turns into copper metal. (Zinc electrode loses mass, copper electrode gains mass) I hope this was clear to you :) -Sincerely Norwegian Chemistry and Biology student :)

[@FirstRisingSouI]

Thanks. I have always found it strange that I can master quantum physics and general relativity at the graduate level, but freshman chemistry is still hard for me.

[@Benjen97]

That's cool. I've never done physics, but I'm doing HL chemistry and biology atm. And off the two I find chemistry really interesting

[@tpstrat14]

Being a space science junky, the “electron vacuum” bit was worth its weight in gold in my attempt to understand this.

[@MrCOPYPASTE]

And yet you surpass the quality of your videos. Thanks for being awesome :)

[@MagicallyEmily]

IT ALL MAKES SENSE NOW

[@kingivanthe3rd]

i think youre the next bill nie for anything educational because my teachers are showing you for history

[@laurahornback6983]

This makes prepping for the MCAT a LOT easier.

[@nerdynadine5892]

I have a first year chem exam tomorrow and this is so great! Awesome review tool!

[@gizmobirdman]

I applaud anyone who didn't have to consistently positive video to take in every sentence he said

[@soso14pinkya]

It's weird that when you made videos about Thermochemistry I was a junior in high school studying it. Now I'm studying Electrochemistry ._. THANK YOU..

[@markyisser9004]

don't get me wrong, i really really respect your work and what you are doing. And, i do not believe you meant for it to be insulting (hopefully anyway); but, personally, it still 'strikes a chord' in midst of all this intellectual endeavoring. Yours' truly, Appreciative Subscriber

[@mitalipatil8068]

Love love love itt....around 30 pages of my textbook in 9 minutes :3

[@bravefire4103]

I can't believe he really just licked that battery. Science is trully an art.

[@bronkdog]

this was put together very well... this also reminded me how I hated the chemistry lingo.. oxidation is loosing elections but not be confused with reduction which is gaining but however the reducing agent is.... general chemistry wasn't one of my most enjoyable classes. to anyone that plans on taking it, I would recommend taking higher level physics and math first if possible. i see a lot of people get discourage from this course that have a lot of potential.

[@the_cosmic_alexolotl2282]

I take the AP Chem exam in a week...

[@SpencerJenkins45]

+Alexandra Grabowski same here

[@vivekpatel4661]

I'm screwed

[@Kelly_C]

Vivek Patel lol same

[@gn.punpun]

what is ap exactly? where are you from? and what level of education are you in

[@MegaDeathadder]

Vertigo Immanotgonnatellya wow i have to learn this stuff just to get into medical school, in my country you need to get 3 B's on the same certificate not resets. Questions are very hard and syllabus has a lot more content lol. Americans have it so easy

[@Hannah123605]

The annoying moment where my test is always the week before these episodes come out with a way to actually get stuff

[@Kasatome]

It's confusing but. . . Electron flow is from Cathode(Negative) to Anode(Positive). What we measure in electricity is not the flow of the electrons exactly, but rather the flow of positive charge from Anode to Cathode.

[@Cnix92]

click on settings button , click playback speed -0.75, slow it down to your liking :) thank me later

[@tobicoul]

point of correction in battries the anode is negative and the cathode is positive. you need tho not that mistake +CrashCourse

[@LiveGoodPhilippines888]

yes he talks fast but this man has done a great job, and if you want to understand him you can just read the subtitles below then pause the video at a time, so that you can get what he is saying. . . this video is so informative, anyway.

[@MonkeyDLuffy-xr4fl]

In batteries the Anode is the negative terminal and the Cathode is the positive! In electrolysis and recharging it's the other way around...

[@ruchi4965]

I'm pretty sure that in a voltaic/galvanic cell the cathode is positive and the anode is negative. He said the opposite around 2:50? I'm confused does anyone know?

[@Hoolcolbery]

+Ruchi A Well he's right i that in Electrochemistry oxidation the anode and cathode are determined, not by whether the electrode is positive or negative but by where oxidation and reduction occurs, with the oxidizing electrode being the anode and the other the cathode.

[@LindaengelustrupBlogspot]

It depends: In a galvaic element the anode is negative but in an elecrolysis an anode is positive. Remember: the rule "ANton the OX is scaRED of the CAT" still counts. (OXidation by the ANode and REDuction by the CATode) if I understand it somewhat correctly that is =)

[@aslamvillan5417]

Yes, The negative terminal or electrode where the electrons generates (Anode) and positive terminal where the electron terminates (cathode).

[@darkcoffeebean7299]

Have my SAT 2 in chem in two days. Thank god for CrashCourse :)

[@jeslinephoon4887]

speaking at a perfect pace gotta say I luv this

[@thorstenkramer8295]

Hi First I have to say: Great job, I love Crash course, Scishow..... an waiting for crash course physics ! but here i heared: "if the Voltage is high, each electron can do a lot more work"....??? I think, each electron can do the same work, but higher voltage drives more of them, which leads to higher work?

[@lukedickie9503]

just had the chemistry HSC exam, this would of been a lot of help if it was uploaded like 10 hours earlier then it was

[@joeserneem853]

Chemistry raised to the power of awesome. That's what I think of all your crash courses, Hank! THNX!

[@cascer123]

I could've used this yesterday while studying for the chemistry exam I had today

[@rishabhkapoor6542]

Great video FYI Mn4O2 is manganese (I) oxide-Mn's charge is+1 NOT manganese (Iv) oxide. MnO2 is manganese (IV) oxide