Next Video: ruclips.net/video/iWqUWwyPkSs/видео.html Chemistry PDF Worksheets: www.video-tutor.net/chemistry-basic-introduction.html Final Exams and Video Playlists: www.video-tutor.net/
For anyone wondering why at 7:40 the answer is -2.20V it's because electrolytic cells can have negative cell potentials which is the difference between galvonic cells. When electrolytic cells have negative cell potential values they need energy to run. It's like when your smartphone is dead; you need to recharge it first before it can run again
another neat way to determine which cell potential is "flipped" is which is more negative. The more negative a cell potential is, the more it wishes to be oxidized. And when we oxidize reactions in problems similar to these we will flip the reaction, which also can flip the sign to its corresponding reduction potential
Keep in mind when he says that it has to be positive, he means the overall potential for the entire cell, and it only applies to galvanic cells. Electrolytic cells can be negative because they are powered by an external source. You can also use the value of the cell potential to determine if the reaction will be in equilibrium (Ecell = 0) or if it’s spontaneous (Ecell = positive) or non-spontaneous (Ecell = negative). Hopefully you knew this already but I’m adding it just in case :)
@@AverageMED He's wrong. An electrolytic cell, by definition, has a negative Ecell. Always negative. Never positive. First time I've seen him make a big mistake in a video.
Thank you so much for this video, it is exactly what I was looking for! One question: for cases like Ag/Mg reaction, why does multiplying the Ag equation by 2 not change the cell potential at all? I keep thinking that if I have to move twice as many electrons, the potential should double.
hi dude the basic thing of this chapter is electrode potential do not change with how many moles , pressure , temperature you add the ep donot change . i think my answer would clear your doubt .
Can anyone explain equation 3 ? Thank you. In contrast to a galvanic cell,the most positive standard reduction half reaction within an electrolytic cell is the one that experiences oxidation. With that in mind, Why did he reverse iron half reaction and not the Br half reaction (where Br would be our anode and Fe be our cathode? Ered of cathode - E red of anode.
Br is the one receiving the electron therefore it is a reduction and Fe is losing electron therefore it’s a oxidation. Knowing that reduction is cathode and oxidation is anode. Using the formula Ered-Eox or Ecathode - Eanode = 1.09-(0.77) which is 0.32
In an electrolytic cell, you have to put in energy to do the electrolysis, so Gibbs free energy is positive here, which means cell potential needs to be negative, not positive.
Where the hell comes india man.. can you see anybody commenting usa france Germany etc.. don't make india look bad because of your stupidity. . I am indian also but for god sake don't write everywhere i am from india love from india
yes it does. for calculating cell potential in standard conditions (1M) use the method in this video. for concentrations other than 1M use nernst equation
First you say the cell potential has to be positive, then you introduce a nonspontaneous reaction (were the potential is negative) without explaining. Im confused. So i wouldve had the wrong answer if i flipped the Standard for aluminum so i could do 1,66 - 0,535?
hmm I'm not quite understanding how he got +0.21V for Q2. After reversing the iron's rxn, it becomes an oxidation (anode) with E= +0.44. So should it be: E cell = E cat - E ano = -0.23 - 0.44 which is
@@sandeepsammy9480 Sure thing. For this question, it'd be helpful to arrange the half-rxns in the decreasing order of standard cell potential values - we will have Ni (-0.23V) then Fe (-0,44V) so Ni+2 rxn is reduction (cathode) and Fe+2 is oxidation (anode). The formula (Cathode - Anode) works according to the standard potential values of reduction half-rxn. Thus, since anode = -0.44, Cathode - Anode = -0.23 - (-0.44) = 0.23 + 0.44. Hope this helps :)
Electrode potential is an intensive property and non additive in nature so we can't directly add it the way you did. Instead what we have to do is add all the reactions and equate it's Gibbs free energy to the final free energy. Could you pls solve this confusion for me?
when we calculate the cell potential we have to do subtraction. The formula is cathode - anode. In the first example you added the values and now i am confused.
I just wanted to know if the balancing of the electrons changed the cell potential for my homework. Thankfully I have found somewhere where it says that it does not change. Where else can I find the answer to this question? Like actually I was surfing this channels videos to find this answer.
Dont you think when we subtract one from other with opposite charge the net result with sign of those which is larger term...as you did in case of secnd e.g ...suggest me please
@@sajidmehmood6976 If Ni is used as oxidation it's wrong cause with half - reactions, one half - reaction must be reduced and the other oxidized . Both of them can't be oxidized. Fe is already oxidized
Do they often give equations along side😢.Here at my school you don't dare expect any cell equation💔. Please do a video for assigning which one should be oxidized or reduced when two elements are under consideration. Or send me a link if it is already available . That is just my challenge presently😢
If a galvanic cell, invert the reaction that will result in a positive E. If an electrolytic cell, it depends what they are looking for. The "E" can be negative, positive, or zero. Thus it doesn't matter which you invert.
wait, isn't getting the cell potential of a galvanic cell done in a way in that, E(oxidation)-E(reduction)? And it seems like we do not gave to change the signs when flipping the equations around....
On question 3) (7:35) you don't multiply Fe^2+ potential by two. So the overall result should be -0.45v not +0.32v. If this is the answer why galvanic cell result negative?
It is super helpful to look at the charges of each elements first! (for example, Fe^2+ in reactant side but on product side, it has 3+ charge, then it is getting bigger, which is oxidation= Anode). However, if the charge was Br2 itself and with a zero charge in reactant side and in product side, it is -1 charge, then it is getting less, which is reduction= cathode. It is super helpful to think of an number line! Going to left (decreasing charge= Cathode) and going to right (got bigger number of charges = Anode). But don't get confused, reduction means gaining ELECTRONS and oxidation means losing ELECTRONS, not charges!!
An easier and quicker way is looking at the electric potentials of both half reactions and picking the largest electric potential. That will be your Ecathode , so you can subtract that with the lower electric potential (your Eanode) to get your overall cell potential. For example, for #1 you pick the 0.8V since it is the larger number and subtract that with -2.37V which will give you 3.17V.
Next Video: ruclips.net/video/iWqUWwyPkSs/видео.html
Chemistry PDF Worksheets: www.video-tutor.net/chemistry-basic-introduction.html
Final Exams and Video Playlists: www.video-tutor.net/
for years people have been wanting to see the owner of this golden voice
fax
When do you think he will reveal his face?
True 😢 like just tell the username !! We will find you
Yes
For years people have been wanting to hear the voice of this golden typer😜😜
dude, you legit explain things much better than my professor and my two textbooks combined together.
100% it only took me 5 minutes of this video to understand the whole thing. Teachers need to learn from this guy
@Idris Jalen wow my account got hacked in the process because instapwn is a total scam!
@@Guy_OFFICIAL Both of these accounts are bots which were created at the same time to make Instapwn appear more authentic.
lets clone him and let the clones replace all teacher on the planet...
For a brighter future!
I hope you aren't sick of hearing this; THANK YOU!!! I was stuck on this unit for two days. Your explanations are very clear and concise.
Me too I was stuck and couldn't skip it either and he came and saved me
this channel is legit helping me a lot with all my struggles in chem.
Me too
Fr
For anyone wondering why at 7:40 the answer is -2.20V it's because electrolytic cells can have negative cell potentials which is the difference between galvonic cells.
When electrolytic cells have negative cell potential values they need energy to run. It's like when your smartphone is dead; you need to recharge it first before it can run again
thanks!
How did u get -2.20V at problem 3?
THANKS!
another neat way to determine which cell potential is "flipped" is which is more negative. The more negative a cell potential is, the more it wishes to be oxidized.
And when we oxidize reactions in problems similar to these we will flip the reaction, which also can flip the sign to its corresponding reduction potential
Thanks!!!
Now we are in 2024 and i'm watching ur vidéos all i want to say to you it's just you're perfect and thaaaaaank you for everything😻
Thank you dude you are saving me from having anxiety attacks. Thank you thank you thank you.
6 years and this is still golden.....i hope next generation finds this helpful too
Do you know how many lives you’re saving by making these videos ? 🥺 thank you so much 😭😭
Im 10 min this guys explain 4 lessons better than a "AP chem" teacher did in combined of 4-5 hours =_=
You're the best man. I friggin' love you!
😂😂😂😂
You gay
@@HimanshuRaj-ry2gx to whom are u saying that??? 🤔🤔🤔
Bro quit dreaming
The heros we need (sakht launda)
First three seconds and you already answered my question I had thanks man!!!
so fast huh
fr so simple and i was wondering that after like 2 assignments and test tmr
Sus
Never knew that a study ASMR also exists ❤
You just explained what my teacher told us in 1 and half hour in freaking 10 mins
true dat my teacher just confused me so much that i had to revisit the whole thing again
Thank you! Using you for entrace test. Happy teacher's day!
"A standard cell potential has to be positive" can't believe my professor never mentioned that in lecture man haha
Keep in mind when he says that it has to be positive, he means the overall potential for the entire cell, and it only applies to galvanic cells. Electrolytic cells can be negative because they are powered by an external source. You can also use the value of the cell potential to determine if the reaction will be in equilibrium (Ecell = 0) or if it’s spontaneous (Ecell = positive) or non-spontaneous (Ecell = negative). Hopefully you knew this already but I’m adding it just in case :)
@@avationmusic can an electrolytic cell be positive?? I am having a hard time wondering why they ever would be
@@AverageMED He's wrong. An electrolytic cell, by definition, has a negative Ecell. Always negative. Never positive. First time I've seen him make a big mistake in a video.
@@user-pr5py8cw9x yeah i was gonna say by definition it has to be negative
what do you do when you're not told if it's electrolytic or galvanic?
the way he says reaction🥺❤️3:41
Thank you, I can't describe how much I appreciate the lessons you give us.
I’m studying chemistry in Greece and your videos are amazingly helpful..Thank you ;) !!!
Thank you!!!
*Organic Chemistry Tutor*
I love your voice! Your videos are so helpful!
Thank you so much for this video, it is exactly what I was looking for! One question: for cases like Ag/Mg reaction, why does multiplying the Ag equation by 2 not change the cell potential at all? I keep thinking that if I have to move twice as many electrons, the potential should double.
Cell potential is an intensive property, so it will not change even if the number of moles vary.
hi dude the basic thing of this chapter is electrode potential do not change with how many moles , pressure , temperature you add the ep donot change . i think my answer would clear your doubt .
In Standard cell potential don't we subtract the cell potential of cathode from anode as per formula?
Bkr video h nhi hai isko knowledge
Mohammad nasir you do, but he reversed one of the reactions, that’s why he still got the correct answer despite adding them.
@@shubhamsinghhh99 I think you should check yourself before accusing him.
yeap it should, that's how is shown on the books
His half rxn are standard hence he can choose to reverse the other one
Explanation was too simple.... Thanks 😊
1 bit of constructive feedback: invest in a quality microphone.
I love your videos; you are great at explaining things.
You don't know how much thankful I am .. i understood many other stuff too
Thank you ❤
Thank you very much for this my friend, much obliged
Explained wonderfully!
Thanks!!
THANK YOU SO MUCH ILY YOU ARE SAVING MY GRADES
Can anyone explain equation 3 ? Thank you.
In contrast to a galvanic cell,the most positive standard reduction half reaction within an electrolytic cell is the one that experiences oxidation.
With that in mind, Why did he reverse iron half reaction and not the Br half reaction (where Br would be our anode and Fe be our cathode? Ered of cathode - E red of anode.
Br is the one receiving the electron therefore it is a reduction and Fe is losing electron therefore it’s a oxidation. Knowing that reduction is cathode and oxidation is anode. Using the formula Ered-Eox or Ecathode - Eanode = 1.09-(0.77) which is 0.32
Thankss! Ezpz to understand ur explanation ! My brain feels relaxed now😃 hopefully i will get my quiz n test excellent marks!🥺
How did u get -2.20 ..I got +2.20 in the last question
In an electrolytic cell, you have to put in energy to do the electrolysis, so Gibbs free energy is positive here, which means cell potential needs to be negative, not positive.
Great.please make video how to affect using active and inert electrode on the product of electrolysis
should we multiply the E°cell value when equation is being multiplied?
No since the standard potential is in volts and not in volts/mole.
You saved me some tears... Yet again
Interesting. It’s a bit confusing when it comes to the redox flow battery. Can you do it for iron redox flow battery reactions.
I like ur way of speaking .You are just fabulous.👍👍👍👍👏👏👏
You are best ...
India 🇮🇳
Where the hell comes india man.. can you see anybody commenting usa france Germany etc.. don't make india look bad because of your stupidity. . I am indian also but for god sake don't write everywhere i am from india love from india
dude. if i had a million bucks i would give it all to you
Hi question, does molarity of the substances affect the cell potential?
yes it does. for calculating cell potential in standard conditions (1M) use the method in this video. for concentrations other than 1M use nernst equation
Please tell me why souldn't we need to balance the last example?
please dont ever stop making videos please
Bro this guy is a better teacher then my actual teacher
I always have to speed these up, but good stuff
U are a legend professor. God bless U😇😇
Why i didnt watch your videos a couple of years ago 😣
Seriously man🙁🙁🙁🙁
In 10:56, +109, pls tell me how to get that number..
Best explanation
Amazing explanation dude 👏👏👏👏👍👍👍👌👌👌👌
This is awesome way to understand... Thanks👍👍👌👌
loving this content
First you say the cell potential has to be positive, then you introduce a nonspontaneous reaction (were the potential is negative) without explaining.
Im confused.
So i wouldve had the wrong answer if i flipped the Standard for aluminum so i could do 1,66 - 0,535?
same here! XP
for galvanic cell, that's the rule that it must be positive. in electrolytic cell it can be either
Where did they get the value of Voltage?
hmm I'm not quite understanding how he got +0.21V for Q2. After reversing the iron's rxn, it becomes an oxidation (anode) with E= +0.44. So should it be: E cell = E cat - E ano = -0.23 - 0.44 which is
Even I have the same doudt and going through the comments...so that anyone can reply me .
If your doudt has clarified .. can you please tell ?
@@sandeepsammy9480 Sure thing. For this question, it'd be helpful to arrange the half-rxns in the decreasing order of standard cell potential values - we will have Ni (-0.23V) then Fe (-0,44V) so Ni+2 rxn is reduction (cathode) and Fe+2 is oxidation (anode). The formula (Cathode - Anode) works according to the standard potential values of reduction half-rxn. Thus, since anode = -0.44, Cathode - Anode = -0.23 - (-0.44) = 0.23 + 0.44. Hope this helps :)
@@sandeepsammy9480 Also it's a galvanic cell meaning Cathode - Anode always > 0
@@venusz6134 thankyou ...I understood ..thanks for the clarification
how did you come up with the reduction potentials?
Electrode potential is an intensive property and non additive in nature so we can't directly add it the way you did. Instead what we have to do is add all the reactions and equate it's Gibbs free energy to the final free energy. Could you pls solve this confusion for me?
Yea thats what im thinking
You're the best! Thank you.
when we calculate the cell potential we have to do subtraction. The formula is cathode - anode. In the first example you added the values and now i am confused.
In that formula we use reducation potential where as he used oxidation and red potential respectively
Bro
+0.80-(-2.37)=+0.80+(2.37)
Still the same bro.
I wanna hug and kiss this guy. Thank you so much!
You are a real teacher!
Thanks!!!❤️
YOU SAVED ME AGAIN!!!
I learned in class the formula for ecell was to subtract ecathode and eanode? Can you explain why you are adding them?
This is the same problem I'm facing 😭
clear lecture.... thank u
Forgalvanic cell cell potential hs to be positive. For electrolytic cell it can be negative positive or zero.
I just wanted to know if the balancing of the electrons changed the cell potential for my homework. Thankfully I have found somewhere where it says that it does not change. Where else can I find the answer to this question? Like actually I was surfing this channels videos to find this answer.
omgg thank you so much! This literally helped me alot!
this video was helpful
I will do my best
Dont you think when we subtract one from other with opposite charge the net result with sign of those which is larger term...as you did in case of secnd e.g ...suggest me please
As in Ni and Fe eg. The net sign is negatve...
I have read this eg in another book with Ni used as oxidation
@@sajidmehmood6976 If Ni is used as oxidation it's wrong cause with half - reactions, one half - reaction must be reduced and the other oxidized . Both of them can't be oxidized. Fe is already oxidized
Thank you so much
God 😇🙏👼 bless you all😄😇
Do they often give equations along side😢.Here at my school you don't dare expect any cell equation💔. Please do a video for assigning which one should be oxidized or reduced when two elements are under consideration. Or send me a link if it is already available . That is just my challenge presently😢
Will the cell potential value for each reaction be given ?
Sorry I need clearification on problem 3 as I think you didn't need to change the sign of the 0.77V to negative as the equations were in order.
Wow! Thanks man you're helping me alot ❤🙏
i was soooo confused, thank you sooooo much
The question 4 was kinda weird to me, hope you could explain more
The second example why you replace the first equation not the second?
In your second example, why did you reverse Fe and not Ni?
Why cell potential of lead acid battery is 2volt if lead and sulpher potential is much lower ????
thank you sm :) god bless u. sending love your way
How do we know which reaction we have to reverse??? Either one or two 🤔🤔
Thanks dude
Thank you po
when the electrons are present on the same side then which reaction is to be inversed and on what basis?
If a galvanic cell, invert the reaction that will result in a positive E.
If an electrolytic cell, it depends what they are looking for. The "E" can be negative, positive, or zero. Thus it doesn't matter which you invert.
Do we have to remember the data as you have shown in example 3..
thanks for always making it all seem easy :))
So when can this formula be used? E= Ered-EOX
wait, isn't getting the cell potential of a galvanic cell done in a way in that, E(oxidation)-E(reduction)? And it seems like we do not gave to change the signs when flipping the equations around....
But if the cell potential on both sides is both positive
Should the cell potential for electrolytic cells always be negative (so deltaG is +) since its nonspontaneous via the equation G = -nFE?
yes my same thoughts. especially for the Br2 2Fe2+ one he does at like 7:30
Saeemm
On question 3) (7:35) you don't multiply Fe^2+ potential by two. So the overall result should be -0.45v not +0.32v. If this is the answer why galvanic cell result negative?
because its asking for an electrolytic cell.
U didn't told which one will come on anode or cathode ???
It is super helpful to look at the charges of each elements first! (for example, Fe^2+ in reactant side but on product side, it has 3+ charge, then it is getting bigger, which is oxidation= Anode). However, if the charge was Br2 itself and with a zero charge in reactant side and in product side, it is -1 charge, then it is getting less, which is reduction= cathode. It is super helpful to think of an number line! Going to left (decreasing charge= Cathode) and going to right (got bigger number of charges = Anode). But don't get confused, reduction means gaining ELECTRONS and oxidation means losing ELECTRONS, not charges!!
Thank you
5:51 how did you get those cell potentials
An easier and quicker way is looking at the electric potentials of both half reactions and picking the largest electric potential. That will be your Ecathode , so you can subtract that with the lower electric potential (your Eanode) to get your overall cell potential. For example, for #1 you pick the 0.8V since it is the larger number and subtract that with -2.37V which will give you 3.17V.
Thank you, sir
What if you don’t know if it’s an electrolytic cell or galvanic cell?