Balancing Half Equations in Redox Reactions

hi guys welcome to another chem tutorial so today we are looking at balancing half equations so again this is um um suitable for any ncaa level 2 and nc level 3 chemistry students um so let&#39;s get into it so today not so long of intro let&#39;s just get straight into some fencing half equations so half equations is absolutely essential um for redox you need to understand um what is happening in terms of what&#39;s turning into what and how do you balance equations because that&#39;s what actually happens in the in the reaction because when we think about redox i mentioned this in my oxidation number video it is to do with the it&#39;s mostly redox directions mostly applicable in electricity generation or you know batteries and all that sort of thing so anything that involves electricity involves electrons and redox is pretty much just movement of electrons okay so let&#39;s go into this so i listed down the four steps of balancing a half equation now again just for nca students we normally just look at acidic condition for basic conditions so again if you ib or doing ib or cambridge probably you can find that in somewhere else because it&#39;s just one extra step um so if you understand the basic stuff it shouldn&#39;t be too hard to do the basic conditions okay so let&#39;s have a look so we balance unique elements anything that&#39;s not h or no um balance or by adding water balance the h by adding h plus ions and then you are changing the charge so the best way to if you want to you can take a screenshot and then but the best way is that we are going to go into today&#39;s recording with some questions and i&#39;ll start with i&#39;ll start with the most difficult one okay now there are four steps and you need to ask yourself these four steps every time you balance off equations especially if you&#39;re just starting with them with this particular concept because for some really easy ones you can just stick you can skip a lot of the steps like because it doesn&#39;t involve like not everything have o&#39;s not everything have ages you don&#39;t need to do those steps um but it is good to practice at the beginning just ask yourself do i have done this okay not required to the next one not required to the next r i need to do this and just go through the list and you know do five balancing half equations and then you don&#39;t need to listen anymore you just become you just become a habit okay so first thing first let&#39;s get to the dichromate and the chromium half equation so first thing first i look at the cr i look at the cr so step one now i&#39;m just going to do this in one one go like one i normally do this on whiteboard i write it down like four times just to show how it works um but you know the power of youtube you can the videos recordings you can listen to it you know play back and hear it again if i&#39;m going too fast so let&#39;s go so with the cr there are two crs on the left hand side there&#39;s one cr on the right hand side now don&#39;t get confused with the charges the charges simply means if again the electrons lost electrons it has nothing to do with the quantity of how many of these atoms you have so for the chromium i have two here one here so the first thing you need to do is to balance the rule number one and put the two before the cr3 plus and i will say at least 50 of the people that get like say with the because pro chromic dichromate lines this this particular combination is one of the hardest ones it&#39;s probably the hardest ones at level two and one of the hardest ones at level three and if you if you and this fifty percent of people that get this wrong is because it misses four st at the first step they just go straight into the holes into the edges into the electron they forget about the two in front of the cr3 plus that&#39;s step one step two there i have seven holes on the left hand side i need to have seven overs on the right hand side and i balance the holes by adding water so because by adding seven water i&#39;ve added seven dollars so i got seven oh there i got seven i was here happy happy but when you added water you also added edges so you added now this is the thing when you add a seven h2o no i because i&#39;m i do this for a living so i can see it straight away so you got seven lots of h2o one lot of h2o is two h&#39;s and there are seven h2 molecules so seven times two you have 14 h&#39;s on the right hand side you have 14 h&#39;s you need 14 h&#39;s on the left-hand side so it&#39;s 14 h plus if you don&#39;t put the plus we are going to be very very unhappy because what does the h plus actually stand for it stands for acidic conditions so go back to your acids and bases again so h plus means it&#39;s acidic or which minus means is alkaline okay so i&#39;ve done my h plus i&#39;ve done my h&#39;s okay now the last thing which is something that people get confused of most of the time is they get confused with the electron they don&#39;t know where it goes because when we do all these balancing by adding h pluses by adding um all h2os h pluses we are you know and then balancing these we are actually changing the charge but you need to understand that the charge you know the purpose of balance equation is that in any reaction you don&#39;t create or destroy anything they simply turn into something else so if you started with x amount of particles you should make x amount of particles so you know the conservation of energy or the conservation of material so in this case we need to look at the charge and if you&#39;re not so confident with us just follow my step just look at each individual um each individual one separately all right look at the cr2072 minus you look at the top right hand side corner i&#39;m just going to start highlighting all of these you look at the top right hand side corner for the charge this is minus two um because that&#39;s what i&#39;ve highlighted and then this is plus one for one h but look at that number in front of it there are 14 h plus h pluses so this is plus 14. so on the left hand side i have negative 2 and negative 4 plus 14 combined together that&#39;s positive 12. let&#39;s look at the right hand side um each cr has a plus 3 but again there are two crs so that&#39;s going to be two times plus three that&#39;s going to be plus six and the water has nothing because there&#39;s nothing there so it&#39;s a big fat zero so on the right hand side my oxidation my charge is plus six my left hand side is plus 12. we add electrons to the more positive side this is more positive by how many by 6. so we add 6 electrons to balance this particular equation okay and another tip because we are learning uh we&#39;re learning redox you know oxidation reduction reaction if you have electrons on the left hand side of the equation you have a reduction reaction okay so redox okay so you have electrons on the left hand side and then that&#39;s a reduction reaction okay so that&#39;s a very easy way for you to identify because the electrons are being gained all right if the electrons on the right hand side the electrons are being lost okay so let&#39;s do another one let&#39;s do the another difficult one um so here it goes if i do the m and all four minus let&#39;s go back to the black color quite like that color um mno4 minus turning into m and two plus so step one let&#39;s look at the mn one mn one mn sweet nothing needs to be done that&#39;s four o&#39;s four h2o because i need the four o&#39;s and by adding four o&#39;s i added eight h&#39;s so i need eight h plus on the left-hand side to balance the h&#39;s and then let&#39;s look at the charge this is negative one this is plus eight all together my left hand side is plus six and this is plus two this is zero combined together this is plus two again if you wonder where i get those charges from just highlight the top right hand side corner and then ask yourself what is the charge now this is plot seven this is plus two the left hand side is more positive by five so i add five electrons again electrons on the left-hand side this is a reduction reaction okay practice banks makes perfect um let&#39;s do some more so those are the hardest ones um let&#39;s do some i mean i mean if you you know this is i minus turning into i2 if you&#39;re on pause pause the video and just give it a go yourself you know read the rules and then give it a go yourself but i&#39;m just gonna explain it um so you can pause any time you want so this is how mine is turning into i2 so first rule is balance the eyes um there&#39;s two i on the right hand side there&#39;s only one eye here so i need to balance that 2i minus 2i2 now step 2 step 3 don&#39;t apply because they know those no h&#39;s so you don&#39;t need to do any of those let&#39;s look at the left hand side again we&#39;ll highlight the top right hand side corner that charge nothing there this has a charge of negative let&#39;s do it slowly negative one times two so this is negative two okay because there are two negative one so it&#39;s negative two on the right hand side this is an element so zero so you&#39;re going from negative two to zero and this is where people get confused you add electrons to the more positive side i know it&#39;s hard to believe but zero is more positive than negative two okay so yeah two electrons on this side okay and then let&#39;s do one more before we wrap it up if you&#39;re going from fe to plus to fe3 plus and then there&#39;s no balancing involved whatsoever other than the last step there&#39;s no first step one fe one fe done no h&#39;s no o&#39;s none of that done look at the charges is plus two this is plus three this is more positive by one electron and that is your half equation balanced okay so it&#39;s very very straightforward um let&#39;s see it&#39;s it&#39;s um yeah very straightforward so just one in doubt come back to these rules and um you should be alright so one thing that i might actually do let&#39;s do the four equations let&#39;s balance the four equations why don&#39;t we balance four equations let me give you another example let&#39;s say if i&#39;m going from a l to a of three plus and then the other reaction i&#39;m going let&#39;s pick something really easy let&#39;s go from br 2 to br minus okay so this is a redox reaction um so we can apply what we learned so far so the oxidation number of that is zero the oxidation number there is plus three this is zero this is negative one if you still can&#39;t get the hang of this watch my oxidation number video okay so how do we balance it this is plus three this is zero so i need three electrons on this side now for this one i need to balance it first step because they&#39;re two brs there&#39;s only one br so i need to put a big two in front and by doing that um this used to be negative one charge but now they&#39;re two of it so it&#39;s negative two this side is zero so i need two electrons on the left hand side so you know remember redox electrons on the right hand side this is oxidation electrons on the left hand side this is reduction and this is how you check that you&#39;ve done it correctly because if you have electrons on the same sides you have done something wrong a hundred percent you will never ever have electrons on the same sides if you&#39;re doing redox okay so next step these are the four half equations how do you balance the full equation so four equation is when you combine these two things together and you can see they have a common denominator which is the electrons and i deliberately picked this one because this doesn&#39;t give us a nice and easy um cancellation because we what we want to do you can think about it the oxidation loses the electrons and the reduction reaction gains electrons so both you know you need both of them to react so when the number of electrons being lost and the electrons being gained are not the same we need to balance them in a way that they will you know will change a ratio that they will release and gain the same number of electrons so we got three electrons here we got two electrons here so when we do the full equation i want to make sure the number of electrons must be the same they need to be the same and how do i make them the same is by multiplying this whole thing by two because that&#39;ll give me six electrons multiplying this whole thing by three which will give me six electrons and then if i have six electrons on the right hand side six electrons on the left hand side then that will mean yep same number of electrons being gained same number of electrons being um being lost so everything else should just be a copy paste okay so we need the electrons to be the same and if they are already the same simply combine them okay so in this case i need to go so i need to multiply everything by two so this is where at the beginning if you&#39;re doing this at the beginning just be patient there you go just just write it down again but then i multiply everything by two the next one i multiply everything by three just copy them down it&#39;s not that hard um because if you don&#39;t do it this way at the beginning you will forget because you most likely multiply everything by two in the top one then you forgot one of them then that ruins everything now can you see now my six electrons on the right and six electrons on the left they will cancel each other out so what does that mean that means i&#39;m gonna combine everything let&#39;s do it this way that means you&#39;re gonna combine everything on the left hand side together and everything on the right hand side together so this is just become a copy paste business copy arrow copy and this is your full equation okay so this is probably one of the harder ones let me give you one more because this might involve some cancellation so if i go from let&#39;s give you one more um let&#39;s have something that has water in it um all right here&#39;s another no3 minus turning to another and this is a reduction reaction so i need an oxidation reaction uh this is not the best one let me think let&#39;s get rid of that let&#39;s get rid of that let&#39;s use our awesome and level minus because this is the easiest one to be honest what to give examples for um we already balance it as well because this part we&#39;re not looking at the balancing we&#39;re looking at the full equation so if i have what is something that i mean i can just revert okay okay i&#39;m just late at night i&#39;m just gonna pick the opposite okay so if i have this particular reaction let&#39;s balance it um this is going to be for water this is going to be eight h plus and this is going to be five electrons okay um now if we balance this one so the n is already balanced i look at the o there&#39;s a two o&#39;s three hours i need water and then by adding water i did two h&#39;s i had two edges and look at the charge this is zero this is zero this is negative one this is plus two so i need to add i need to add one more electron on the right hand side okay now let&#39;s get rid of this so this is my four equation my half equation i got five electrons on the left hand side i got one electron on the right hand side so first thing first they are on opposite sides so that means i must have done that correctly so what does that mean let&#39;s balance it okay and not let&#39;s write a full balance equation i mean the easiest way well that&#39;s not the easiest only one way is to multiply this entire thing by five why because i need five electrons because i have five electrons in my reduction reaction so it&#39;s five no two plus five water turn into five and no 3 minus plus 10 h plus plus 5 electrons just so the electron numbers on this on opposite sides are the same now remember we will need to add everything on the left hand side of the equation together and everything on the right hand side of the equation to get the text because that&#39;s what is that what balance equation does it combines them together so we are going to have mno4 minus plus oops um plus eight h plus plus five and no two plus five h2o now i run a bit of space because i wrote too big um that&#39;s gonna turn into um m and 2 plus plus 4 h2o plus 5 and no minus n03 minus plus 10 h plus and now you notice i don&#39;t even write the electrons because there&#39;s no point okay because they already cancelled each other out actually yeah it&#39;s fine you guys can understand this all right so just remember just try fit them in a straight line i just run out of space because i write so big when i&#39;m using the stupid tablet okay now if you write it down like this as you find the answer we will mark it down the reason being in mathematics you don&#39;t do this you know 2x plus 4 equals 3x and then you leave that as your final answer that&#39;s not acceptable you have to solve what axis can you see the things i&#39;m highlighting now the things i&#39;m highlighting now you can see the same they&#39;re the same type of element that they&#39;re the same thing different quantity but the same ion or molecule or element that i&#39;m highlighting they are on opposite sides so they need to cancel okay so there&#39;s five water here there&#39;s four water here they need to cancel so you need to simplify it so it&#39;s going to be mno4 minus plus 5no2 plus 1 h2o y because the 5 and the 4 cancel out i have one left and that&#39;s going to turn into m and 2 plus plus 5 and or 3 minus plus 2 h plus because this 10 and this 8 cancels out to be 2. okay so this is a more correct one and it&#39;s more simplified and that&#39;s what you need to do for this particular internal both level two and level three okay so regardless of which level you are you need to be able to do the basics okay so at level two this is pretty much you know you need to do observations and things like that um so i&#39;ll probably cover that a little bit more in detail i i&#39;m i&#39;m just doing the basics um so if you&#39;re someone that&#39;s doing level three cam but are you struggling with the basics you need to do this okay because it doesn&#39;t matter how good your electrochemistry is um if you don&#39;t get this you can&#39;t pass okay um so hopefully this has been helpful um i will so the next few um um episodes will be mainly for the year thirteens um because i&#39;m teaching the year 13 so we&#39;re going to lock down so you know so um all the all the all the things i need to kind of always um prioritize the year 13 because the year 12 storms start the internals yet but i am aware that some schools may have started with the quantitative analysis um so once i&#39;ve done with the redox i will start putting things um you know for the for the for the titration stuff um as well on my youtube channel so stay tuned um like and subscribe if you haven&#39;t share with your friend that are struggling him and like always um hopefully learn something and i&#39;ll see you guys next time bye

hi guys welcome to another chem tutorial so today we are looking at balancing half equations so again this is um um suitable for any ncaa level 2 and nc level 3 chemistry students um so let&amp;#39;s get into it so today not so long of intro let&amp;#39;s just get straight into some fencing half equations so half equations is absolutely essential um for redox you need to understand um what is happening in terms of what&amp;#39;s turning into what and how do you balance equations because that&amp;#39;s what actually happens in the in the reaction because when we think about redox i mentioned this in my oxidation number video it is to do with the it&amp;#39;s mostly redox directions mostly applicable in electricity generation or you know batteries and all that sort of thing so anything that involves electricity involves electrons and redox is pretty much just movement of electrons okay so let&amp;#39;s go into this so i listed down the four steps of balancing a half equation now again just for nca students we normally just look at acidic condition for basic conditions so again if you ib or doing ib or cambridge probably you can find that in somewhere else because it&amp;#39;s just one extra step um so if you understand the basic stuff it shouldn&amp;#39;t be too hard to do the basic conditions okay so let&amp;#39;s have a look so we balance unique elements anything that&amp;#39;s not h or no um balance or by adding water balance the h by adding h plus ions and then you are changing the charge so the best way to if you want to you can take a screenshot and then but the best way is that we are going to go into today&amp;#39;s recording with some questions and i&amp;#39;ll start with i&amp;#39;ll start with the most difficult one okay now there are four steps and you need to ask yourself these four steps every time you balance off equations especially if you&amp;#39;re just starting with them with this particular concept because for some really easy ones you can just stick you can skip a lot of the steps like because it doesn&amp;#39;t involve like not everything have o&amp;#39;s not everything have ages you don&amp;#39;t need to do those steps um but it is good to practice at the beginning just ask yourself do i have done this okay not required to the next one not required to the next r i need to do this and just go through the list and you know do five balancing half equations and then you don&amp;#39;t need to listen anymore you just become you just become a habit okay so first thing first let&amp;#39;s get to the dichromate and the chromium half equation so first thing first i look at the cr i look at the cr so step one now i&amp;#39;m just going to do this in one one go like one i normally do this on whiteboard i write it down like four times just to show how it works um but you know the power of youtube you can the videos recordings you can listen to it you know play back and hear it again if i&amp;#39;m going too fast so let&amp;#39;s go so with the cr there are two crs on the left hand side there&amp;#39;s one cr on the right hand side now don&amp;#39;t get confused with the charges the charges simply means if again the electrons lost electrons it has nothing to do with the quantity of how many of these atoms you have so for the chromium i have two here one here so the first thing you need to do is to balance the rule number one and put the two before the cr3 plus and i will say at least 50 of the people that get like say with the because pro chromic dichromate lines this this particular combination is one of the hardest ones it&amp;#39;s probably the hardest ones at level two and one of the hardest ones at level three and if you if you and this fifty percent of people that get this wrong is because it misses four st at the first step they just go straight into the holes into the edges into the electron they forget about the two in front of the cr3 plus that&amp;#39;s step one step two there i have seven holes on the left hand side i need to have seven overs on the right hand side and i balance the holes by adding water so because by adding seven water i&amp;#39;ve added seven dollars so i got seven oh there i got seven i was here happy happy but when you added water you also added edges so you added now this is the thing when you add a seven h2o no i because i&amp;#39;m i do this for a living so i can see it straight away so you got seven lots of h2o one lot of h2o is two h&amp;#39;s and there are seven h2 molecules so seven times two you have 14 h&amp;#39;s on the right hand side you have 14 h&amp;#39;s you need 14 h&amp;#39;s on the left-hand side so it&amp;#39;s 14 h plus if you don&amp;#39;t put the plus we are going to be very very unhappy because what does the h plus actually stand for it stands for acidic conditions so go back to your acids and bases again so h plus means it&amp;#39;s acidic or which minus means is alkaline okay so i&amp;#39;ve done my h plus i&amp;#39;ve done my h&amp;#39;s okay now the last thing which is something that people get confused of most of the time is they get confused with the electron they don&amp;#39;t know where it goes because when we do all these balancing by adding h pluses by adding um all h2os h pluses we are you know and then balancing these we are actually changing the charge but you need to understand that the charge you know the purpose of balance equation is that in any reaction you don&amp;#39;t create or destroy anything they simply turn into something else so if you started with x amount of particles you should make x amount of particles so you know the conservation of energy or the conservation of material so in this case we need to look at the charge and if you&amp;#39;re not so confident with us just follow my step just look at each individual um each individual one separately all right look at the cr2072 minus you look at the top right hand side corner i&amp;#39;m just going to start highlighting all of these you look at the top right hand side corner for the charge this is minus two um because that&amp;#39;s what i&amp;#39;ve highlighted and then this is plus one for one h but look at that number in front of it there are 14 h plus h pluses so this is plus 14. so on the left hand side i have negative 2 and negative 4 plus 14 combined together that&amp;#39;s positive 12. let&amp;#39;s look at the right hand side um each cr has a plus 3 but again there are two crs so that&amp;#39;s going to be two times plus three that&amp;#39;s going to be plus six and the water has nothing because there&amp;#39;s nothing there so it&amp;#39;s a big fat zero so on the right hand side my oxidation my charge is plus six my left hand side is plus 12. we add electrons to the more positive side this is more positive by how many by 6. so we add 6 electrons to balance this particular equation okay and another tip because we are learning uh we&amp;#39;re learning redox you know oxidation reduction reaction if you have electrons on the left hand side of the equation you have a reduction reaction okay so redox okay so you have electrons on the left hand side and then that&amp;#39;s a reduction reaction okay so that&amp;#39;s a very easy way for you to identify because the electrons are being gained all right if the electrons on the right hand side the electrons are being lost okay so let&amp;#39;s do another one let&amp;#39;s do the another difficult one um so here it goes if i do the m and all four minus let&amp;#39;s go back to the black color quite like that color um mno4 minus turning into m and two plus so step one let&amp;#39;s look at the mn one mn one mn sweet nothing needs to be done that&amp;#39;s four o&amp;#39;s four h2o because i need the four o&amp;#39;s and by adding four o&amp;#39;s i added eight h&amp;#39;s so i need eight h plus on the left-hand side to balance the h&amp;#39;s and then let&amp;#39;s look at the charge this is negative one this is plus eight all together my left hand side is plus six and this is plus two this is zero combined together this is plus two again if you wonder where i get those charges from just highlight the top right hand side corner and then ask yourself what is the charge now this is plot seven this is plus two the left hand side is more positive by five so i add five electrons again electrons on the left-hand side this is a reduction reaction okay practice banks makes perfect um let&amp;#39;s do some more so those are the hardest ones um let&amp;#39;s do some i mean i mean if you you know this is i minus turning into i2 if you&amp;#39;re on pause pause the video and just give it a go yourself you know read the rules and then give it a go yourself but i&amp;#39;m just gonna explain it um so you can pause any time you want so this is how mine is turning into i2 so first rule is balance the eyes um there&amp;#39;s two i on the right hand side there&amp;#39;s only one eye here so i need to balance that 2i minus 2i2 now step 2 step 3 don&amp;#39;t apply because they know those no h&amp;#39;s so you don&amp;#39;t need to do any of those let&amp;#39;s look at the left hand side again we&amp;#39;ll highlight the top right hand side corner that charge nothing there this has a charge of negative let&amp;#39;s do it slowly negative one times two so this is negative two okay because there are two negative one so it&amp;#39;s negative two on the right hand side this is an element so zero so you&amp;#39;re going from negative two to zero and this is where people get confused you add electrons to the more positive side i know it&amp;#39;s hard to believe but zero is more positive than negative two okay so yeah two electrons on this side okay and then let&amp;#39;s do one more before we wrap it up if you&amp;#39;re going from fe to plus to fe3 plus and then there&amp;#39;s no balancing involved whatsoever other than the last step there&amp;#39;s no first step one fe one fe done no h&amp;#39;s no o&amp;#39;s none of that done look at the charges is plus two this is plus three this is more positive by one electron and that is your half equation balanced okay so it&amp;#39;s very very straightforward um let&amp;#39;s see it&amp;#39;s it&amp;#39;s um yeah very straightforward so just one in doubt come back to these rules and um you should be alright so one thing that i might actually do let&amp;#39;s do the four equations let&amp;#39;s balance the four equations why don&amp;#39;t we balance four equations let me give you another example let&amp;#39;s say if i&amp;#39;m going from a l to a of three plus and then the other reaction i&amp;#39;m going let&amp;#39;s pick something really easy let&amp;#39;s go from br 2 to br minus okay so this is a redox reaction um so we can apply what we learned so far so the oxidation number of that is zero the oxidation number there is plus three this is zero this is negative one if you still can&amp;#39;t get the hang of this watch my oxidation number video okay so how do we balance it this is plus three this is zero so i need three electrons on this side now for this one i need to balance it first step because they&amp;#39;re two brs there&amp;#39;s only one br so i need to put a big two in front and by doing that um this used to be negative one charge but now they&amp;#39;re two of it so it&amp;#39;s negative two this side is zero so i need two electrons on the left hand side so you know remember redox electrons on the right hand side this is oxidation electrons on the left hand side this is reduction and this is how you check that you&amp;#39;ve done it correctly because if you have electrons on the same sides you have done something wrong a hundred percent you will never ever have electrons on the same sides if you&amp;#39;re doing redox okay so next step these are the four half equations how do you balance the full equation so four equation is when you combine these two things together and you can see they have a common denominator which is the electrons and i deliberately picked this one because this doesn&amp;#39;t give us a nice and easy um cancellation because we what we want to do you can think about it the oxidation loses the electrons and the reduction reaction gains electrons so both you know you need both of them to react so when the number of electrons being lost and the electrons being gained are not the same we need to balance them in a way that they will you know will change a ratio that they will release and gain the same number of electrons so we got three electrons here we got two electrons here so when we do the full equation i want to make sure the number of electrons must be the same they need to be the same and how do i make them the same is by multiplying this whole thing by two because that&amp;#39;ll give me six electrons multiplying this whole thing by three which will give me six electrons and then if i have six electrons on the right hand side six electrons on the left hand side then that will mean yep same number of electrons being gained same number of electrons being um being lost so everything else should just be a copy paste okay so we need the electrons to be the same and if they are already the same simply combine them okay so in this case i need to go so i need to multiply everything by two so this is where at the beginning if you&amp;#39;re doing this at the beginning just be patient there you go just just write it down again but then i multiply everything by two the next one i multiply everything by three just copy them down it&amp;#39;s not that hard um because if you don&amp;#39;t do it this way at the beginning you will forget because you most likely multiply everything by two in the top one then you forgot one of them then that ruins everything now can you see now my six electrons on the right and six electrons on the left they will cancel each other out so what does that mean that means i&amp;#39;m gonna combine everything let&amp;#39;s do it this way that means you&amp;#39;re gonna combine everything on the left hand side together and everything on the right hand side together so this is just become a copy paste business copy arrow copy and this is your full equation okay so this is probably one of the harder ones let me give you one more because this might involve some cancellation so if i go from let&amp;#39;s give you one more um let&amp;#39;s have something that has water in it um all right here&amp;#39;s another no3 minus turning to another and this is a reduction reaction so i need an oxidation reaction uh this is not the best one let me think let&amp;#39;s get rid of that let&amp;#39;s get rid of that let&amp;#39;s use our awesome and level minus because this is the easiest one to be honest what to give examples for um we already balance it as well because this part we&amp;#39;re not looking at the balancing we&amp;#39;re looking at the full equation so if i have what is something that i mean i can just revert okay okay i&amp;#39;m just late at night i&amp;#39;m just gonna pick the opposite okay so if i have this particular reaction let&amp;#39;s balance it um this is going to be for water this is going to be eight h plus and this is going to be five electrons okay um now if we balance this one so the n is already balanced i look at the o there&amp;#39;s a two o&amp;#39;s three hours i need water and then by adding water i did two h&amp;#39;s i had two edges and look at the charge this is zero this is zero this is negative one this is plus two so i need to add i need to add one more electron on the right hand side okay now let&amp;#39;s get rid of this so this is my four equation my half equation i got five electrons on the left hand side i got one electron on the right hand side so first thing first they are on opposite sides so that means i must have done that correctly so what does that mean let&amp;#39;s balance it okay and not let&amp;#39;s write a full balance equation i mean the easiest way well that&amp;#39;s not the easiest only one way is to multiply this entire thing by five why because i need five electrons because i have five electrons in my reduction reaction so it&amp;#39;s five no two plus five water turn into five and no 3 minus plus 10 h plus plus 5 electrons just so the electron numbers on this on opposite sides are the same now remember we will need to add everything on the left hand side of the equation together and everything on the right hand side of the equation to get the text because that&amp;#39;s what is that what balance equation does it combines them together so we are going to have mno4 minus plus oops um plus eight h plus plus five and no two plus five h2o now i run a bit of space because i wrote too big um that&amp;#39;s gonna turn into um m and 2 plus plus 4 h2o plus 5 and no minus n03 minus plus 10 h plus and now you notice i don&amp;#39;t even write the electrons because there&amp;#39;s no point okay because they already cancelled each other out actually yeah it&amp;#39;s fine you guys can understand this all right so just remember just try fit them in a straight line i just run out of space because i write so big when i&amp;#39;m using the stupid tablet okay now if you write it down like this as you find the answer we will mark it down the reason being in mathematics you don&amp;#39;t do this you know 2x plus 4 equals 3x and then you leave that as your final answer that&amp;#39;s not acceptable you have to solve what axis can you see the things i&amp;#39;m highlighting now the things i&amp;#39;m highlighting now you can see the same they&amp;#39;re the same type of element that they&amp;#39;re the same thing different quantity but the same ion or molecule or element that i&amp;#39;m highlighting they are on opposite sides so they need to cancel okay so there&amp;#39;s five water here there&amp;#39;s four water here they need to cancel so you need to simplify it so it&amp;#39;s going to be mno4 minus plus 5no2 plus 1 h2o y because the 5 and the 4 cancel out i have one left and that&amp;#39;s going to turn into m and 2 plus plus 5 and or 3 minus plus 2 h plus because this 10 and this 8 cancels out to be 2. okay so this is a more correct one and it&amp;#39;s more simplified and that&amp;#39;s what you need to do for this particular internal both level two and level three okay so regardless of which level you are you need to be able to do the basics okay so at level two this is pretty much you know you need to do observations and things like that um so i&amp;#39;ll probably cover that a little bit more in detail i i&amp;#39;m i&amp;#39;m just doing the basics um so if you&amp;#39;re someone that&amp;#39;s doing level three cam but are you struggling with the basics you need to do this okay because it doesn&amp;#39;t matter how good your electrochemistry is um if you don&amp;#39;t get this you can&amp;#39;t pass okay um so hopefully this has been helpful um i will so the next few um um episodes will be mainly for the year thirteens um because i&amp;#39;m teaching the year 13 so we&amp;#39;re going to lock down so you know so um all the all the all the things i need to kind of always um prioritize the year 13 because the year 12 storms start the internals yet but i am aware that some schools may have started with the quantitative analysis um so once i&amp;#39;ve done with the redox i will start putting things um you know for the for the for the titration stuff um as well on my youtube channel so stay tuned um like and subscribe if you haven&amp;#39;t share with your friend that are struggling him and like always um hopefully learn something and i&amp;#39;ll see you guys next time bye

Transcript for:Balancing Half Equations in Redox Reactions

Transcript for:
Balancing Half Equations in Redox Reactions