I owe you my entire education oh my goodness, I’m home schooling AS & A2 level and your videos have me confident on things I didn’t even understand in GCSES when I was in school, thankyou so much Eliot, I couldn’t have done it without all this help 🙏
This is one of the topics I find hardest to understand, with all the half equations and full equations, but I feel more confident after watching this. I'll need to try some examples to get fully comfortable with it.
Thanks for your excellent work of teaching Chemistry via Skye. I have one remarks in this lesson is that you forgot to emphasise that the half reactions of redox involved equilibrium. You wrote the half equations of redox as if they were one-way reactions. Rather then reversible. This simple mistake can make the whole topic much more difficult to understand than is necessary. All the best, Dr Youssef El Aziz
Thank you so much for these amazing videos! Has really helped me get through a bulk of revision! Although it isn't related to redox questions in particular, I have noticed in past papers that they ask you to write an 'overall equation'. Do you use redox reactions or simply cancel out like compounds? Thank you!
Your videos are a great help, and I have them on my iPod so that I can watch them on the bus before school. You could team up with myGCSEscience and so an A level version of everything if you teamed up with some other teachers.
pstasiw I'm glad to hear it! Yeah, I guess that's a possibility. I thought that I had seen that the GCSEscience guy had started charging for his videos though...
As usual these videos are so helpful however, I am confused at an oxidation state, at 7:22 The Nitrogen in NH4 +. I believed that when the hydrogen was not named first in the compound it had a charge of -1 not +1 like in NaH. Then the nitrogen would have an oxidation state of +5 not -3. This is probably just me, however if you could clear this up it would be much appreciated.
Hello sir, fantastic video as always! i just have one question though, you stated the definition of reduction is: where an element/compound gains electron(s). So,at minute 14:42 why is the di-chromate ion undergoing reduction when it's actually losing electrons (because it's going from 2- to 3+). Thank you very much for your time and effort sir!
Rangahatimuhmon Thanks for the kind words! I think you might be a bit confused - I shall try and clear some things up. I'm going to assume that you've got the -2 from the fact the the dichromate ion has a charge of -2. This would sort of make sense, but remember that the dichromate ion contains oxygen too. Because of that, we look to work out the oxidation state of just the chromium. The overall charge of the dichromate is -2. Each oxygen has an oxidation state of -2. There are 7 oxygens. 7 x -2 = -14. Because the overall charge is -2, the 2 chromiums must account for the +12 that's missing. That means that each chromium is in fact +6. In that sense, it is the CHROMIUM that is being reduced, from +6 to +3. Does that make sense at all?
E Rintoul Yes sir, thanks a lot, So would it be correct to say that cr2 =12 and therefore you divide it by 2 to get a single cr which would give you +6, whereas you do not divide the 2cr as it is already on its own (meaning cr will be +3)? P.s i have some questions regarding the video you did on halogens, can i fire away? ;) Thanks a lot my man
E Rintoul You know my whole unit 2 book are notes derived from your videos, I haven't listened in class (because i don't like my teachers teaching method), nor have i read the aqa book. Your videos are extremely beneficial! Ok, on to my questions: In your Halogens video, you stated as you go down group 7, the oxidising power decreases. In other words, the ability to lose an electron decreases in strength as you go down group 7. Why is that? if the size of group 7 atoms become larger as you go down the group, wouldn't that mean an increase in distance from and nucleus and therefore and increase in shells and shielding? Wouldn't that therefore mean the ability to lose an electron will be EASIER as the outer electrons are further away from the nucleus. Edit: I just realized right now as i was typing this to you that the reason for this could be that the amount of protons that are increasing (as you go down the group) overpower the increase in shells and shielding? Either way, please clarify!
Rangahatimuhmon Well thank you again for the kind words! Out of curiosity, what is it about your teacher's methods that you don't like? Right I see what you're saying. And what you're saying kind of makes sense. Except for a tiny, tiny detail. Oxidation is loss electrons. Correct. As size increases, the outer shell electrons are further away and so the attraction is weaker. This means that the outer electrons are lost more easily. Correct. But that isn't what I said. I said that the oxidising power decreases. That is the ability to oxidise. As such, an oxidizing agent is reduced. Another way to look at it would be to say that down group 7, the elements are less easily reduced. Does that help at all?
Thank You for this video , i just have 2 questions. Oxidation is loss of electrons which will form a positive ion right . 15 mins into the video cr2o7(2-) is reduced to 2cr(3+). Can you please explain to me how this is reduction and not oxidation? Also isnt it oxidation as the oxidation number increased from -2 to +3?
Ishtiaq Hussain Hi! You are correct that oxidation is loss of electrons. And you are correct that SOMETIMES this will lead to a positive ion being formed. The better way to look at oxidation, and reduction, is to think about the terms in relation to the oxidation state of the elements in question. This brings me to your point... You are looking at the overall charge of the dichromate ion being 2- and asking how, when it is forming a 3+ ion, this is reduction and not oxidation? Well, we aren't using the entire dichromate ion. We don't care so much for the oxygen, instead we are looking at the chromium. In the dichomate ion, EACH chromium has an oxidation state of +7 and when the REDUCTION occurs, this chromium is REDUCED to +3. Does that make any sense?
Ishtiaq Hussain E Rintoul In the dichromate ion, doesn't EACH chromium have an oxidation state of +6, rather than +7? As the formula is Cr2o7^2-, so the oxygen, represented by an 'o', has an oxidation state of -14, since the overall ion is -2, the Cr2 must also be +12 as this will equal -2 overall. But because we want to know each Cr we divide 12 by 2 to give +6. Please can you tell me where you have got the +7 from?
Thank you very much this is helpful! But suppose you have to balance something like this: MnO4- + H+ + no2- ----> Mn2+ + h20 + No3- You can't use the same method by adding the h2o to balance the oxygens right?
AM I INCORRECT Oxidation is loss of electrons Reduction is gain of electrons So at 12:10 aren't they both oxidation. Hear me out. The first one is oxidation because of the reasons he stated. HOWEVER the second one goes from a 2- charge to a 3+ charge. This means it went from 2 additional electrons to 3 less electrons. This means that electrons were lost. So it must be oxidation. If I am incorrect please explain why as I am confused.
What ISA prep is that... I know that the AQA ISA deadline has long passed! In all honesty, as much as I would love to do everything, I've just not got the time! Tonight I'm going to try and get a couple of videos done, but I don't think I'm going to be able to squeeze anything ISA related in, I'm afraid! By all means ask any questions through my channel and I'll try to help!
Could you do/do you have a video of balancing more complex redox reactions? With additional reactants and products that aren’t necessarily subject to redox?
Thank you for another great video, prior to watching the vid and even after it, I get +3e on both sides rather than +6e, Is this also correct or have I fallen short somewhere?
Boro Jen xX It perhaps wasn't mentioned. I can't cover everything and AQA will more than likely throw some bits in to trick you at points! In H2O2, oxygen is -1 so don't always think of it as -2!
Hi, I have my AS Chemistry EMPA coming up after the Easter holidays...I don't suppose theres any chance you could make a video tutorial to help us prepare for these practicals and empa papers?
xxpinkladiesxx In all honesty, probably not. Due to the sporadic nature of the papers, it would be very difficult to make a "one size fits all" video, if you get what I mean. If you have any questions though, please fire away!
Amazing video again Just to clarify will we be expected to know the oxidation states or do you get given them in the exam. PS. Have you completed a lesson for mass spectrometry and infrared spectroscopy Thanks really very helpful
moneyhoneyhoney You are expected to know some oxidation states - oxygen (remember that it is -1 in peroxide), hydrogen, group 1 metals, group 2 metals, halogens etc. The questions will normally want you to work out the oxidation state of nitrogen or sulphur for example in compounds of hydrogen and oxygen etc. Hope that helps!
Hello Sir, Im going to be retaking Chem2 this year however your videos are now in new specifications. Would there be a big effect for me by revising your videos??
+Bartholomew Pang Nope. The videos have stayed almost exactly the same - the only real difference at Year 1 (what was AS) is that they now do more on equilibria (what you do at A2 in fact) and mass spec is different.
Danyaal Qureshi Yup! The ones that you need to know are the ones of chlorine and water and chlorine and sodium hydroxide. There's no reason that they couldn't give you another equation that was disproportionation though and get you to work things out based on that.
Hi! I love your videos as always. However, I do have a question, when balancing the half equation you figured out the oxidation state of the compound but you didn’t use it. However, my teacher said that you use the oxidation states to determine how many electrons you would add to make them balance, and then to balance the charges you add the hydrogen ions, and then to balance the equation you add water molecules. I was wondering if that was right and just another way to balance redox reactions, or if that is actually wrong and my teacher is just confused. Thank you so much for this video as it seems much simpler than what she was explaining and now I’m a little confused because I don’t know what method is correct.
I don't know what to put as my name hi! I would always suggest balancing the specie being reduced/oxidised then oxygen using water, then the hydrogen using H+ ions and finally the charge using electrons. I guess there are other ways to do it but I've always found this method to work!
mr biggle might be too late but I think he’s accounting for a single chromium atom, oxygen(-2*7)= -14 Potassium(1*2)=2 the total of these would give you -12 for a chromium molecule divide by two for a single chromium atom.. think and the charge would be +6 to balance the charges ... I think x
Alex Ruding Unfortunately, you are expected to know them. To be fair, there aren't a huge number (hydrogen, oxygen, group 7, group 1 etc.). They normally give you compounds and then expect you to work out the oxidation state of an element in that compound.
Any chance you could do Group 7, Halogens and Group 2 Alkaline E.M Thanks in advance, Mainly how to write the simplest ionic equations and what we need to remember for the exam!.
F.J Vinzenz I honestly don't know. I would stay WELL away from writing a minus. The reason I did it was to show what is happening. In terms of convention, electrons are written as being gained on the opposite side as this makes it much easier to then combine half-equations.
Hi thanks for these videos!! When you balance the reduction equation, you balanced the oxygen first, what happens if there is no oxygen in the equation? Some other methods balance the electrons first but I don't really understand that.
Hi, Laura! It all depends on the half-equation given. For example, balancing Cr2O72- --> Cr3+ would require water, hydrogen ions and electrons. However, Fe3+ --> Fe2+ would only require electrons. Balance in this order... 1) balance the species present (Cr2O72- --> 2Cr3+ - note that the Cr has been balanced by doubling it) 2) deal with any unbalanced oxygens using water on the other side 3) balance hydrogens using hydrogen ions 4) balance charges using electrons If one of these steps is missing, it doesn't matter; just follow the others and you'll be fine! If you're still struggling, post me an example of what's confusing you and I'll try to help!
can someone please help me im confused between AQA and caie as i am a caie student and i want to learn from these videos is the content also same for me pls can someone explain
Of course! Potassium is +1 (this you just need to know - it's in group 1) Oxygen is -2 (again you need to know this) 2x1 (from the K2) + 7x-2 (from the oxygen) = -12 This means that the 2 chromiums must together add up to +12 (for a compound, the sum of the oxidation states must equal its charge). From this, each chromium must be +6. Does that make any sense?
Of course! Potassium is +1 (this you just need to know - it's in group 1) Oxygen is -2 (again you need to know this) 2x1 (from the K2) + 7x-2 (from the oxygen) = -12 This means that the 2 chromiums must together add up to +12 (for a compound, the sum of the oxidation states must equal its charge). From this, each chromium must be +6. Does that make any sense?
Great video, you're amazing. Many thanks. Vanadium is prepared by reducing vanadium(V) oxide with silicon. Write an equation for this reaction. (1 mark) Is it possible for you to help me with this question?
Thanks for the kind words! Without looking, I would guess that it's going to be a case where the silicon is causing displacement to occur thereby leaving the vanadium on its own, making silicon dioxide in the process. In terms of an equation... 2V2O5 + 5Si --> 5SiO2 + 4V That looks like it could be about right?
Thank you so much for the videos mate! I have a teacher who does one side of the course and I don't understand his teaching methods at all :/ so cheers for these
8 years ago and still helping chemistry students. Hero
Still the best man around
10yrs ago and he still is
I owe you my entire education oh my goodness, I’m home schooling AS & A2 level and your videos have me confident on things I didn’t even understand in GCSES when I was in school, thankyou so much Eliot, I couldn’t have done it without all this help 🙏
Took my teacher 3 lessons to explain this worse than what you just did in 16 minutes. Thank you so much
This is one of the topics I find hardest to understand, with all the half equations and full equations, but I feel more confident after watching this. I'll need to try some examples to get fully comfortable with it.
Boro Jen xX I LOVE redox! I'm glad it helped!
E Rintoul I used to hate it before I watched this lol, now I think it's fun
Duck off
I find organic the hardest yet its sooo interesting
@@maazahmed2341 same
Thanks for your excellent work of teaching Chemistry via Skye. I have one remarks in this lesson is that you forgot to emphasise that the half reactions of redox involved equilibrium. You wrote the half equations of redox as if they were one-way reactions. Rather then reversible. This simple mistake can make the whole topic much more difficult to understand than is necessary.
All the best,
Dr Youssef El Aziz
Your videos are honestly the only reason I'm surviving my Inorganic Chemistry modules for Biology, thank you so much!
Once again, thank you so much for your helpful videos! I finally understand redox! :)
***** No problem!
Physical Chemistry revision done wooo :)
InternHits Gowan lad!
Thank you very much for taking the time and effort to make these videos! They've really helped to consolidate and clarify classwork!
lol this has been spinning my head for nearly 24 hours now, thanks :)
10 years later and bro is still the goat
you made this so much easier to understand as my chem teacher just cannot
So glad I’m not the only student who sees a redox question and immediately wants to cry
REDOX IS YOUR FRIEND
You're saving my a-level chemistry single-handedly cheers
I genuinely love you so much, without you I would've known close to nothing. I hope you are well!
Thank you so much for these amazing videos! Has really helped me get through a bulk of revision! Although it isn't related to redox questions in particular, I have noticed in past papers that they ask you to write an 'overall equation'. Do you use redox reactions or simply cancel out like compounds? Thank you!
Your videos are a great help, and I have them on my iPod so that I can watch them on the bus before school. You could team up with myGCSEscience and so an A level version of everything if you teamed up with some other teachers.
pstasiw I'm glad to hear it! Yeah, I guess that's a possibility. I thought that I had seen that the GCSEscience guy had started charging for his videos though...
As usual these videos are so helpful however, I am confused at an oxidation state, at 7:22 The Nitrogen in NH4 +. I believed that when the hydrogen was not named first in the compound it had a charge of -1 not +1 like in NaH. Then the nitrogen would have an oxidation state of +5 not -3. This is probably just me, however if you could clear this up it would be much appreciated.
I know this is 8 years ago but I was confused about this too thank you for pointing it out
I'm the worst at this but this vid has given me more confidence 😭💕 #Not all superheroes wear capes
damn i finally understand this... what would i do without you?
Thanks for helping me out Sir! I understand this topic a lot more now, also loved the accent lol.
Hello sir, fantastic video as always!
i just have one question though, you stated the definition of reduction is: where an element/compound gains electron(s). So,at minute 14:42 why is the di-chromate ion undergoing reduction when it's actually losing electrons (because it's going from 2- to 3+).
Thank you very much for your time and effort sir!
Rangahatimuhmon Thanks for the kind words!
I think you might be a bit confused - I shall try and clear some things up.
I'm going to assume that you've got the -2 from the fact the the dichromate ion has a charge of -2. This would sort of make sense, but remember that the dichromate ion contains oxygen too. Because of that, we look to work out the oxidation state of just the chromium.
The overall charge of the dichromate is -2. Each oxygen has an oxidation state of -2. There are 7 oxygens. 7 x -2 = -14.
Because the overall charge is -2, the 2 chromiums must account for the +12 that's missing. That means that each chromium is in fact +6.
In that sense, it is the CHROMIUM that is being reduced, from +6 to +3.
Does that make sense at all?
E Rintoul Yes sir, thanks a lot,
So would it be correct to say that cr2 =12 and therefore you divide it by 2 to get a single cr which would give you +6, whereas you do not divide the 2cr as it is already on its own (meaning cr will be +3)?
P.s i have some questions regarding the video you did on halogens, can i fire away? ;)
Thanks a lot my man
Rangahatimuhmon Yessss, nailed it, old boy!
And of course you can - fire away!
E Rintoul You know my whole unit 2 book are notes derived from your videos, I haven't listened in class (because i don't like my teachers teaching method), nor have i read the aqa book. Your videos are extremely beneficial!
Ok, on to my questions:
In your Halogens video, you stated as you go down group 7, the oxidising power decreases. In other words, the ability to lose an electron decreases in strength as you go down group 7. Why is that? if the size of group 7 atoms become larger as you go down the group, wouldn't that mean an increase in distance from and nucleus and therefore and increase in shells and shielding? Wouldn't that therefore mean the ability to lose an electron will be EASIER as the outer electrons are further away from the nucleus. Edit: I just realized right now as i was typing this to you that the reason for this could be that the amount of protons that are increasing (as you go down the group) overpower the increase in shells and shielding?
Either way, please clarify!
Rangahatimuhmon Well thank you again for the kind words! Out of curiosity, what is it about your teacher's methods that you don't like?
Right I see what you're saying. And what you're saying kind of makes sense. Except for a tiny, tiny detail.
Oxidation is loss electrons. Correct. As size increases, the outer shell electrons are further away and so the attraction is weaker. This means that the outer electrons are lost more easily. Correct.
But that isn't what I said. I said that the oxidising power decreases. That is the ability to oxidise. As such, an oxidizing agent is reduced.
Another way to look at it would be to say that down group 7, the elements are less easily reduced.
Does that help at all?
This really really helped with oxidation states thank you
A few more examples included in the end would have been better as it would just help to consolidate this.
Also at 12:09 why do we add 6 electrons ?
Thank You for this video , i just have 2 questions.
Oxidation is loss of electrons which will form a positive ion right . 15 mins into the video cr2o7(2-) is reduced to 2cr(3+). Can you please explain to me how this is reduction and not oxidation? Also isnt it oxidation as the oxidation number increased from -2 to +3?
Ishtiaq Hussain Hi! You are correct that oxidation is loss of electrons. And you are correct that SOMETIMES this will lead to a positive ion being formed. The better way to look at oxidation, and reduction, is to think about the terms in relation to the oxidation state of the elements in question.
This brings me to your point... You are looking at the overall charge of the dichromate ion being 2- and asking how, when it is forming a 3+ ion, this is reduction and not oxidation?
Well, we aren't using the entire dichromate ion. We don't care so much for the oxygen, instead we are looking at the chromium. In the dichomate ion, EACH chromium has an oxidation state of +7 and when the REDUCTION occurs, this chromium is REDUCED to +3.
Does that make any sense?
E Rintoul
Oh i understand , thank you for your help . It's greatly appreciated.
Ishtiaq Hussain No problem at all :)
Ishtiaq Hussain E Rintoul In the dichromate ion, doesn't EACH chromium have an oxidation state of +6, rather than +7?
As the formula is Cr2o7^2-, so the oxygen, represented by an 'o', has an oxidation state of -14, since the overall ion is -2, the Cr2 must also be +12 as this will equal -2 overall. But because we want to know each Cr we divide 12 by 2 to give +6.
Please can you tell me where you have got the +7 from?
Umar Ashfaq I got the +7 from a typo! You're completely correct that it is +6 (which I'm sure is in the video somewhere...). Thanks for that!
Thank you very much this is helpful!
But suppose you have to balance something like this: MnO4- + H+ + no2- ----> Mn2+ + h20 + No3-
You can't use the same method by adding the h2o to balance the oxygens right?
AM I INCORRECT
Oxidation is loss of electrons
Reduction is gain of electrons
So at 12:10 aren't they both oxidation.
Hear me out. The first one is oxidation because of the reasons he stated. HOWEVER the second one goes from a 2- charge to a 3+ charge. This means it went from 2 additional electrons to 3 less electrons. This means that electrons were lost. So it must be oxidation.
If I am incorrect please explain why as I am confused.
If I am not wrong the 2- charge is for Oxygen only NOT FOR CR2 , so Cr2 actually has +6 charge and is getting reduced to +3
This is great, ISA prep would really help if could do a video? Thanks
What ISA prep is that... I know that the AQA ISA deadline has long passed!
In all honesty, as much as I would love to do everything, I've just not got the time! Tonight I'm going to try and get a couple of videos done, but I don't think I'm going to be able to squeeze anything ISA related in, I'm afraid!
By all means ask any questions through my channel and I'll try to help!
Could you do/do you have a video of balancing more complex redox reactions? With additional reactants and products that aren’t necessarily subject to redox?
Thank you sir this was really helpful
This is such a deadly topic. 😢😢
so what grade did you get
is there a way to work out for example what CrO7 2- would reduce into? how do you know its Cr3+
Thank you so much for simplifying it for me. This topic confused the hell outta m
Your videos are so helpful, thank you so much 👍🏻👍🏻
🤔
Man, these videos are great
Thank you for another great video, prior to watching the vid and even after it, I get +3e on both sides rather than +6e,
Is this also correct or have I fallen short somewhere?
I don't understand the bit where you said this is reduction and this bit is oxidation. At 14:36
I've just noticed, but oxygen has an oxidation state of +1 in O2F2 and +2 in OF2. I dont think that was mentioned
Boro Jen xX It perhaps wasn't mentioned. I can't cover everything and AQA will more than likely throw some bits in to trick you at points! In H2O2, oxygen is -1 so don't always think of it as -2!
Hi, I have my AS Chemistry EMPA coming up after the Easter holidays...I don't suppose theres any chance you could make a video tutorial to help us prepare for these practicals and empa papers?
xxpinkladiesxx In all honesty, probably not. Due to the sporadic nature of the papers, it would be very difficult to make a "one size fits all" video, if you get what I mean. If you have any questions though, please fire away!
Amazing video again
Just to clarify will we be expected to know the oxidation states or do you get given them in the exam.
PS. Have you completed a lesson for mass spectrometry and infrared spectroscopy
Thanks really very helpful
moneyhoneyhoney You are expected to know some oxidation states - oxygen (remember that it is -1 in peroxide), hydrogen, group 1 metals, group 2 metals, halogens etc. The questions will normally want you to work out the oxidation state of nitrogen or sulphur for example in compounds of hydrogen and oxygen etc.
Hope that helps!
I thought the oxidation state of H2 was 0
Seth Crockett RIP lad
Sir, could you explain more about mediums of the redox reactions? Like in acidic or basic conditions
Hello Sir, Im going to be retaking Chem2 this year however your videos are now in new specifications. Would there be a big effect for me by revising your videos??
+Bartholomew Pang Nope. The videos have stayed almost exactly the same - the only real difference at Year 1 (what was AS) is that they now do more on equilibria (what you do at A2 in fact) and mass spec is different.
Great video I now understand this. Thanks a lot!
hi, thanks for the videos,
are we required to know about disproportion reactions?
Danyaal Qureshi Yup! The ones that you need to know are the ones of chlorine and water and chlorine and sodium hydroxide. There's no reason that they couldn't give you another equation that was disproportionation though and get you to work things out based on that.
thanks!
Hi! I love your videos as always. However, I do have a question, when balancing the half equation you figured out the oxidation state of the compound but you didn’t use it. However, my teacher said that you use the oxidation states to determine how many electrons you would add to make them balance, and then to balance the charges you add the hydrogen ions, and then to balance the equation you add water molecules. I was wondering if that was right and just another way to balance redox reactions, or if that is actually wrong and my teacher is just confused. Thank you so much for this video as it seems much simpler than what she was explaining and now I’m a little confused because I don’t know what method is correct.
I don't know what to put as my name hi! I would always suggest balancing the specie being reduced/oxidised then oxygen using water, then the hydrogen using H+ ions and finally the charge using electrons. I guess there are other ways to do it but I've always found this method to work!
E Rintoul , I often would get it wrong with her method, but with yours I did some practice questions I got them all right! Thank you so much!!!!!
at 10:35, i dont understand how you got Cr to have +6 charge.. can you explain please?
mr biggle might be too late but I think he’s accounting for a single chromium atom, oxygen(-2*7)= -14
Potassium(1*2)=2 the total of these would give you -12 for a chromium molecule divide by two for a single chromium atom.. think and the charge would be +6 to balance the charges ... I think x
@@michelleowusu1622 there's literally no potassium?? i'm so confused
This video was very helpful :) Thank you
LoveLife997 No problem!
Woop! Got all the oxidation states questions correct! x
am i crazy or did he not get the ox state of Cu in (CuCl2)- wrong? shouldn't it have been +2 instead of +1? because Cl2 has a -2 charge...
Thank you. Well explained
OMG I love this video you are amazing THANKS SO MUCH !!!
This isn't a chemistry related question but how do you film your videos ? :)
I use a Wacom Bamboo tablet for the writing onto a blank canvas on Smoothdraw, then I record using Camtasia!
would aqa supply you with some of the oxidation states or are just just supposed to know all the rules?
Alex Ruding Unfortunately, you are expected to know them. To be fair, there aren't a huge number (hydrogen, oxygen, group 7, group 1 etc.). They normally give you compounds and then expect you to work out the oxidation state of an element in that compound.
Thank you so much for this video. I wish i can subscribe more than once
Any chance you could do
Group 7, Halogens and Group 2 Alkaline E.M
Thanks in advance, Mainly how to write the simplest ionic equations and what we need to remember for the exam!.
They're on the list to be done! Watch this space...
Thanks sir
Thank you so much! Do you do A2 videos too?
Mr Rintoul is it accepted if you were to right an electron being minused as shown at 10:00 in the exam
F.J Vinzenz I honestly don't know. I would stay WELL away from writing a minus. The reason I did it was to show what is happening. In terms of convention, electrons are written as being gained on the opposite side as this makes it much easier to then combine half-equations.
Fair enough I only asked out of inquiry not as a suggestion I wouldn't think of doing so, but nonetheless thanks
Hi thanks for these videos!!
When you balance the reduction equation, you balanced the oxygen first, what happens if there is no oxygen in the equation?
Some other methods balance the electrons first but I don't really understand that.
Hi, Laura!
It all depends on the half-equation given.
For example, balancing Cr2O72- --> Cr3+ would require water, hydrogen ions and electrons.
However, Fe3+ --> Fe2+ would only require electrons.
Balance in this order...
1) balance the species present (Cr2O72- --> 2Cr3+ - note that the Cr has been balanced by doubling it)
2) deal with any unbalanced oxygens using water on the other side
3) balance hydrogens using hydrogen ions
4) balance charges using electrons
If one of these steps is missing, it doesn't matter; just follow the others and you'll be fine!
If you're still struggling, post me an example of what's confusing you and I'll try to help!
Hi
That's great so basically if there is no oxygen you don't need to add or balance the oxygen or hydrogen you just need to add the electrons.
Laura Harris Absolutely!
Could you please do a video on Equilibria!
Thanks in advance.
Equilibria is top of my list of videos to make. Watch this space...
Thank you, this video really helped!
Can you do more videos on transition metals
for 10.54, how did you get chromium as +6?
+Blueberry 2 Love watch the video from the beginning, he explains it.
Gain of electrons is reduction 9:33
i will never understand redox reactions ever :(
You will don't worry😊
Shn clashes KEEPIN SPIRITS HIGH RESPECT LAD
Lol
Shn clashes hows your quarantine my man
@@forzeferrari2668 Fine and well, you?
really good channel
thank you bro
why is copper -1? Surely 2x-1=-2 and then the negative overall charge makes it -3?
+303beth (CuCl2)- Because we know Cl= -1 (2x-1=-2) and the overall charge is -1 we want to get from the -2 of the Cl2 to the overall -1 so we add 1 :)
+Shaun Flaherty got it! Thanks :)
can someone please help me im confused between AQA and caie as i am a caie student and i want to learn from these videos is the content also same for me pls can someone explain
is this valid for 2015?
+Banana Splatter Yerp.
2017?
Yes, also 2017.
3.27 what about for a metal from transition and hydrogen will that hydrogen then still be classed as +1?
No, H is +1 except for when it is in a metal hydride. Being bonded to a metal from the transition metals would make it -1.
+A Khan thanks
You’re amazing I hope you know that
I am confused on why chromium in K2CR207 is +6 can you please explain further thanks.
Of course!
Potassium is +1 (this you just need to know - it's in group 1)
Oxygen is -2 (again you need to know this)
2x1 (from the K2) + 7x-2 (from the oxygen) = -12
This means that the 2 chromiums must together add up to +12 (for a compound, the sum of the oxidation states must equal its charge).
From this, each chromium must be +6.
Does that make any sense?
Of course!
Potassium is +1 (this you just need to know - it's in group 1)
Oxygen is -2 (again you need to know this)
2x1 (from the K2) + 7x-2 (from the oxygen) = -12
This means that the 2 chromiums must together add up to +12 (for a compound, the sum of the oxidation states must equal its charge).
From this, each chromium must be +6.
Does that make any sense?
Where is the half reaction in basic medium
thanx!
woot! finally I understand
Whackie E Well done!
you are the best
thank you man, this really helped! This might be a lot to ask, but could you also put up the sheets that you make online so they can be printed?
fuck off
TYYY
At the start he said Na=0 then he said Na=+1 ? I’m confused, someone please explain. Also, my teacher says that K=0 and he’s saying it’s +1, helppp
Na by itself is 0 because it's an uncombined element. However in a compound it's +1 for example in NaCl Na=+1 and Cl=-1 so +1+-1=0
I Cant believe i understand redox. SHOCKER
4:42 can hear bell
Lmao
I have my A level Cape exam Chemistry on Thursday wish me luck
I need to find someone who does this type of thing, but for Physics
we all do 😢
search Dr.Physics A. he might be able to help you!!!
Home time at 4:42 ??? :P
Great video, you're amazing. Many thanks.
Vanadium is prepared by reducing vanadium(V) oxide with silicon. Write an equation for this reaction. (1 mark)
Is it possible for you to help me with this question?
Thanks for the kind words!
Without looking, I would guess that it's going to be a case where the silicon is causing displacement to occur thereby leaving the vanadium on its own, making silicon dioxide in the process.
In terms of an equation...
2V2O5 + 5Si --> 5SiO2 + 4V
That looks like it could be about right?
E Rintoul Thank you sir
Hey for cr2o72- how did u get a charge of 6
(x×2)+(-2×7)=-2
So x equals 6
x means the oxidation number of Cr2
So oxygen has an oxidation number of -2 so (-2×7)
@@glimmerpearl115 thank you
I would do anything for Eliot Rintoul. Anything..
mind = blown. woah. I think i get it though! thank you!
oh God im stressing!!!!! i don’t get half equations :((((
this shit is confusing :(
Lol. Yeah
May I ask, what does "AQA" stand for?
AQA Is the exam board for the subject
Jerry Zhang I stands for Assessment and Qualifications Alliance - it's the exam board!
Alex Baker Ta!
4:42 are you in school?
Is this valid for 2017 🙄
Yeah I think so, this is what I'm doing in my yr 12 A-level course so it's a valid video explaining this all.
Thank you so much for the videos mate! I have a teacher who does one side of the course and I don't understand his teaching methods at all :/ so cheers for these
7:45 2 x (-1) = -2
never mind i forgot to understand that ? + 2 x (-1) = -1
love u
thanx that was helpful :)
I'm glad it was of some help!
Anyone here in 2021? :)
My AS exam is in 2 months and I’m shitting myself
4:43 dingdingdingding