Galvanic Cells

[salut295]

My essay is going to be a peace of cake, thanks to you!

[NeoWizard212]

really nice vid. if anybody's looking for a really nice overview of galvanic cells, i stumbled across a video on some guy's channel called J Co Review... it's short, sweet, and taught me in 5 mins what my prof failed to teach me in 45 lol

[mobinf]

@10:42, shouldnt the zinc in the solution be Zn 2+,as in the ion, not Zn +2 the oxidation state?

[Joeylumadip]

@khanacademy sholdnt the hlaf reaction be Zn--> (Zn^ 2+) + 2e-

[SharathCK]

@Joeylumadip yeah that must have been a typo...

[mrslovvet]

CLARITY!

[wcastillo2501]

cool video it makes sense now

[GenericCoder]

Shouldn't the TotalE = .34 + .7 = 1.04 V ? Instead of 1.1V?

[MaxPaget]

@GenericCoder It was 0.76 see 7:50

[GenericCoder]

@MaxPaget I see I somehow heard him saying .7 instead of .76 V my mind must have been lagging :D.

Thanks.

[Joeylumadip]

@GenericCoder he said .34 + .76

[wowowwiwa]

when mixing elements together, the more active element will go from an element to an ion. viceversa for the less active element. zinc is more active than copper therefore it wants to become an ion, the only way to become an ion is going into liquid. copper is the opposite....thought yaw all should know

[s0m0c]

Great.

[DENlERU]

My Chemistry book says that there won't be any current without the salt bridge, but from this video I understood it as that the salt bridge is needed if you want electrons to flow from the positive side to the negative side for a longer time?

[harshgupta11dec]

Is a cathode positive or negative?

I think cathode is negative because It attracts cations, which are positively charged.

[juanpablodt]

This will help with my final tomorrow. Thanks!

[999anonymosym]

At about 9:25 i think , what can that aqueous solution be , if you can give me a reaction on whats happening to each bar

[rafax8]

I thougth the cathode was negative in galvanic cells!!!!!!!

[andyroo2540]

This is excellent thank you!

[Villacis80]

10:14 Sal Zn is not a transiction metal, but it´s just a tiny error dont worry, it doesnt affect the class :)

[ThePharaoh9993]

@Villacis80 Zn is a transition metal.

[Villacis80]

@ThePharaoh9993 No it isn´t, an element for be considered a transition metal need to have its D orbitals uncompleted it´s because of this that these acquire its propierties that made them to call them "transition", Zn an Sc are in the block D thats right, but both element have complete D orbitals, so these dont present these properties so are not considered as transition metal, if you look the definition of a transition metal you will found that it is an element that has its D orbitals uncomplet

[deadlyXviet]

@Villacis80 Actually it is. Just because it only has one charge doesn't mean it isn't a transition metal.

[cnfused100]

@AmirTunes nd @povern7 its bcz the E value of Cu is less positive than Zn thus making it easier to reduce hope it helps :)

[GreatVgnc]

That was a very good video, but I would suggest going more over spontaneous reactions, as in the Zn redox. reaction

[broli123]

I've watched all the previous videos and have to say this one confused me quite a bit. Could you do a more in depth video explaining the "why's" there seems to be so much assumptions made without any basis.

[poveron7]

The only thing I don't understand about Galvanic Cells is: Why the Zn is the one who Oxidates and the Ca is the one who reduces? Nobody never says that. If you know why, please answer.

Like @AmirTunes asked, I want to know to. Why?

[EurekaTutoring]

Salman has always been one of the best tutors on youtube. In fact, to some people words khanacademy and youtube became almost interchangeable:)

[205049770]

Is it possible you can do a video on cyclic voltammetry, because I am really struggling with that.

[zacmiley12]

So how can you tell which one is the anode and cathode?

Do electrons flow from the anode to cathode?

[topilopi123]

Great vid!

[BarcaB0y10]

redcat anox

[cr7sl7]

@thekobe157 those values are the set standard reduction potential values - they'll be in a table in your book

[shadows1313]

Missing a salt bridge

[thekobe157]

is there's anyone here knows how he got the .34V and the .76V ?.

[thekobe157]

good video though,but how did you get the .34v in half reaction?,and .76v in the other reaction?.

[paelnaz001]

When Sal says 1st year does he mean first year high school ie grade 9? :/ Im in the 12th grade and Im encountering this for the first time. Am I so far behind? D:

[matthewscottgray]

@paelnaz001 No he meant 1st year of school as in kindergarten, are you really that far behind???

[paelnaz001]

@matthewscottgray That was an honest serious question. Don't be such a dick.

[anonymous345]

@paelnaz001

He means 1st year of chemistry, or the first chemistry class you take. Usually people learn this before 12th grade.

[bunnie304]

Thank you so much for making this video!!!! (And all your other ones) They REALLY help a LOT. I was staring at my book for a good hour on the galvanic cell section and NOTHING that I read registered in my head. But thanks to you, within 15 minutes, I have a much better understanding of galvanic cells! You're the BEST! <3

[AnotherBrownKid]

there should be more videos for electrocheistry. these vids are great, but the videos arent organised in a specific order,

[MrLaanix]

I think he sounds like mike portnoy :O  thanks for the video man :D <33

[bitememwah]

thanks Jesus =]



[xinrui9181]

love all your videos! wish u r my professor!!! =)

[jmama57]

Thank you so much for making this video!! It helps me so much getting to SEE chemicals in action instead of just reading it in a book and wondering why elements keep changing place! We are learning about batteries in class now and I was struggling with redox reactions, this helped a lot. Thanks again =)

[TheNothingsomething]

Hi. I have a question. What happens if u increase the concentration in the cells. if u put Cu(s) in CuSO4(aq). The koncentration gows down... If u instead put Zn(s) in ZnSO4(aq), it increases, with a few V... WHY??! What is it that happens...?.. Please help me with this.. Its a big assignment in my school, but i cant figure it out myself..:S...???

[yayaagogo]

what about reduction potential?can u make some video about this?

[riyarsr]

17:38 You meant K+ (Potassium), not Na+ (Sodium).

Na+ will jump into the solution with the Copper bar to replace the Copper jumping out.

[66CrtS]

OWWW!!!!! that hurt! Why did you have to copy and past the reaction down there!! Oww..

[B3rNd92]

great :) im german but your way of explaining is that good that its easier for me to watch your version in english than the teacher's in german

[missfun24]

actually, i hav prob in electrolytic cell. so, can anyone plz tel 2 me whr is best website 4 tat topic? urgent, coz i;m havin exam in 2days. thank u.

[dawance88]

I've never understood the concept of salt bridges until now. You're amazing!!!

[AmirTunes]

How come the Zn wants to jump off of the bar, but the Cu wants to jump onto the bar?

[ELLo1997]

@AmirTunes because Copper is more noble ten Zinc. The non-noble metal is always getting oxidiced (Zn --> Zn+² + 2e-) and the noble one wants to get reduced into his elemental state (Cu+² --> Cu + 2e-).

i hope that helped..

[AmirTunes]

@ELLo1997 Thanks! :) It's just that my chemistry class ended about 6 months ago, but still thanks. :)

[ELLo1997]

@AmirTunes oh ok ^^

[hellokittydimaggio]

@AmirTunes b/c on the activity series table, zinc is more higher on the table than copper, which means its more easily oxidized (go from Zn to Zn2+), if it were the other way around and copper was the solid, I don't think the reaction would take place bu im not sure...

[GenericCoder]

@AmirTunes Its because electronegativity which is the measure of how much atom want to attract electron.

The Zinc electron would tend to jump to the Cu.

[TheAbsoluTurk]

@AmirTunes Being a spontaneous reaction, Cu^2+ is a stronger oxidizing agent. If you have a table, you'll notice Cu^2+ is higher than Zn(s) and on opposite sides.

[KoreaxxLove]

@AmirTunes Well, this reply is really late, but for anyone who is wondering...It occurs spontaneously due to a potential energy difference. The potential energy of electrons is higher in the anode than in the cathode, so electrons flow spontaneously from the anode to the cathode.

[AmirTunes]

Hello, so you say that the copper in the aq solution wants to go back to a solid, and the Zn solid wants to become an aq ion... why do they want to do this? Thanks!

[tom2king]

anode is the +vely charged pole while the cathode is the -vely charged pole.anions are the particles which are attracted towards anode because they are -vely charged while cations are the particles which move towards the cathode because they are +vely charged.

[k00lieo417]

im having so much trouble in my ap chem class but this clears it up ALOT!! :] thank you!! 

[lnvfednk]

isnt it supposed to be a salt bridge too? or am i wrong

[propnash]

browsing YOU TUBE for last 5 hours , finally you are the only one who explained from elementary level.. thank you

[irmb5teS]

thats great, i was wondering, have you done electrolysis?

[MJsDisciple]

thanks sal. one of your best

[atong518]

thank you for the help :)

[amm23ka]

Thankyou SO much.

This is amazing.

[SteroidsR4success]

Lol, this video is just fucking amazing. You wouldve thought that God made it.

[GingleGangle1]

@SteroidsR4success God doesn't talk so much)

[drstingrae]

You should actually contrast Oxidation/Reduction and

Cathode/Anode charges of Galvanic Cell to an Electrolytic cell in which the anode is (+) and Cathode is (-)

[NJKjonasfan4ever]

where did you do your studies?

high school, university, etc

must be real good schools cause your teaching is so good!

[JacobLJacques]

This is ridiculously helpful i have an exam tomorrow ans had to know this concept

[proffezur]

Wow... The US is very behind.

I learned this in grade 12, and learned even more advanced concepts dealing with electro chemistry... But hey what can you do, this is but one reason why CANADA PWNS ALL!!!

[LegoCritic]

@proffezur Dude, get off your pedestal. I'm in the US, I'm in grade 12, and I'm learning this material.

[proffezur]

@LegoCritic Wow Really? Oh I remember when I learned this stuff... Way back in grade 12. >_>

[XyellojelloX]

@proffezur im learning this right now and im in 10th grade :)

[Vali1012]

very useful!thx!

there's also a mnemonic trick to remember the odiation...you say it' the A&O (alpha and omega)

so on the anode theres the oxidation (A&O)

greetz

[desoan]

Preparing for the SAT chem, and the books explain this very poorly. Thanks for the thorough yet easy-to-understand tutorial.

[cow2001]

At the begining, you call Cu 2+ (aq) "molecules", but they're just atoms.

[Blueknightex]

No they're not ;) Cu 2+ are "ions". He calls them molecules because these ions are bonded to another molecule like SO4 2- which makes up a molecule.

[cow2001]

A molecule is a bunch of atoms joined together by covalent bonds. Between copper and sulfate there's an ionic bond, not covalent.

[Blueknightex]

By the way an ionic bond is between a metal and a non-metal.(two 'single' elements).

SO4 2- is not a non- metal it is a "molecule"(made up of elements sulfur and oxygen).

So when Cu 2+ is bonded to it they form a "molecule".

[iGustaf]

They re ions, not atoms

[vkgoku2012]

Your current is flowing in the same direction as electron I think in your physics video on current you kept stressing that current flows in opposite direction.

[vkgoku2012]

When are you gonna cover E knot.

[gamefaq]

tiny errors. but i still enjoyed the entire video. keep it up!

at around 5:30, you left the 2+ charge off the Zn on the right side of the half reaction.

at around 12:30, you said that a current was flowing but you drew an arrow going to the right. maybe you should have said that its the electrons that are flowing to the right since current flows to the left in your galvanic cell.

[khanacademy]

You are correct. Even though the electrons flow from the anode to the cathode, the convention is to say that "current" is flowing from the cathode to the anode. Maybe I'll make another short video to clear this up.