[Music] uh my beginner's guide for balancing equations um the first thing that I want to let you know is that there's no magic to balancing equations there's no secret that you can somehow pick up and all of a sudden become a guru um the reason I made this video is that some students just seem to struggle with how do I even do that or the concept behind it and so if you're really having troubles um hopefully I can kind of clear some of that up and if you're not this is probably not the video for you I would just go Google balancing equations practice and you'll find some really hard ones out that you can try your hand at um so let's get started uh we're going to start the first one we're going to talk about is the combustion of hydrogen um this is the hinden bird explosion and after this we quit putting uh hydrogen gas in into blimps for obvious reasons but essentially what happens is hydrogen combines with oxygen okay so if we look at the equation down here at the bottom the equation as it is is H2 + O2 yields water or H2O and we're going to get a lot of energy out of there as well now the first thing we need to talk about is what these numbers actually mean so this two down here is a subscript and that means that it tells you how many atoms of hydrogen are in a molecule and so this is what the molecule of hydrogen would look like we're going to have two atoms of hydrogen the thing that you need to remember is that you can never change the subscripts subscripts have to remain the same because if you change it you're changing what that molecule actually is and so this would be H2 this would be O2 so we have two oxygen molecules attached together then finally we have H2O and H2O is one oxygen and two hydrogens on either side and so when I look at this a lot of people will just try to go and answer this but maybe we need to step back a little bit and actually look graphically at at what's going on here and so when I look at this I can see here's reactants before the reaction and products and so just looking at it when these are graphically shown you can see that I have two of these uh red oxygen atoms on the left side and only one on the right and so the first thing you might want to do is kind of double that and so let me do that okay so now visually we've got two water molecules and so I've got two Reds on the right side and Two Reds on the left side you'll also notice so that's balanced that the hydrogens are changed and so I have four hydrogens on the right side but I only have two on the left side so now let me click it again and we've got a balanced equation in other words I can never change the subscripts I can never change what these molecules are but when you're balancing equations what you're trying to do is add more of the molecules so you can see that reactants and products will be balanced okay now how do we actually write that out so we can put in front of here what are called coefficients and coefficients are numbers in front of the molecule it tells you how many there are and so there is one oxygen and we never write the coefficient of one and so you don't want to write one as a coefficient if it's a coefficient of one you just leave it blank but let's go over here to H2 you've got this H2 that H2 and so you have 2 H2 so that would be on the left side if we go on to the right side you have this molecule of water this molecule of water and so we have two molecules of water on the right side and so if we step through this this means we have two molecules of H2 so that would be four hydrogens on the left side after you balance an equation you want to go back and look at it make sure it's balanced over here we have two H2S as well so we have four hydrogens we have two Oxygen's on the left side and we have two this coefficient multiplies times this whole thing so we have two oxygen on the right side as well and so we would call that a balanced equation and so hopefully just by looking at it graphically that might help a little bit let's go to the next one next one in a chemistry lab is um you see it all the time this is a bunson burner um and these are some Flames from a bunson burner and so uh a bunson burner Works using a gas called methane and methane is CH4 so if we take a look at methane me looks like this right here it's got one carbon molecule and then it's got four hydrogens attached around the outside and when we when we burn methane what that really means is that we're combining methane with oxygen and we're creating these two things in complete combustion we're com we're creating some carbon dioxide gas that's one carbon two oxygens and then we're creating a little bit of water the other thing we produce is going to be energy okay so if you look at this just graphically on the left side and on the right side the first first thing at least to me that jumps out is that there's way more hydrogen on the left side than the right side so the first thing I could do would be to add another water on the right side so if I've added another water on the right side the the yellow balls on the right now match the yellow balls on the left the carbon there's only one on the left matches the one on the right so we must be getting really close but I've got four Reds on the right and I only have two and so I have to add that as a whole molecule so if I add one more molecule of oxygen now we have a balanced equation so how do we write that out so methane on the left side I have one methane but I'm not going to write the number one how many molecules of oxygen do we have we have two so I'm going to put a two as a coefficient right here now on the right side we only have one carbon dioxide so I'm not going to put a one but there should be uh in your mind a one there and then how much water do we have we have just two waters so I'm going to put two right here now we can go through the whole thing so how many carbons do we have one on the left one on the right how many hydrogen do we have four on the left and this two is Multiplied the subscript so we've got four on the right and four on the left and then if we look at oxygen we've got four on the left and then we've got two oxygen here and we have two oxygen there and so when I'm solving and trying to balance equations I'm not really seeing these um but if that helps you visualize it um then it'll help you do better at that so let's let's try it so the only way to get better at this is to just practice and so let's try a few and I'll show you how I would think through this in my mind so if you look at the first one this is H2O2 which is hydrogen peroxide breaks down into hydrogen gas and oxygen gas okay so how would I how would I set this up well on the left side we've got H2 so if I want to write it out I could so I've got two hydrogens on the left and as far as Oxygen's on the left I've got two oxygens as well and so on the right side how many hydrogens do I have I have two on the right and I have two on the left as well and so this already is a balanced equation and so what do you do if you find a balanced equation that's already balanced you don't do anything to it in other words we'd write a one in front of each of those but we never write ones and so I'm going to leave that one the way it is let's go to the next one on the left side we've got sodium we've got chlorine gas and then we're making table salt and so if you want to write this out you could we've got Na and I've got one of those I've got chlorine on the left side and I've got two of those so that's on the left side that's on the reactant side now let's go to the product side how many sodium do we have we only have one sodium and how many chlorine do we have on the right side well we only have one chlorine so that's a problem because on the uh product side we only have one atom of chlorine and on the reactant side we actually have two so how could I fix that well well let's try to go back let's say I've got too few chlorine on this side so let me just try and add the next step which is to add a two on the right side so by adding a two on the right side I've taken care of my chlorine so on the right side now I have two sodium and two chlorine but I've I've set up another problem in other words I have two sodium on the right side so now I have to balance that over here so I'm going to come back here and write a two over here which that makes this a two okay so now we've got two two two two and that's bad balanced and so the right answer for that one is to put a two in front of the sodium and then a two in front of the sodium chloride and that's a balanced equation remember you can never change the subscrip all right let's do another one another one and so these are getting progressively harder and so I'll give you some tips as far as that goes um the first tip would be this if we look at this one we've got silver sulfide silver and then sulfur and so this eight jumps out right away so on the right side I've got eight sulfur atoms we on the left side I've only got one and so as a bare minimum I'm going to try writing an eight right here let's see what that does well now we have eight sulfur on the left side eight sulfur on the right side but our Silvers aren't matching so on the left side we actually have 16 silver but on the right side we only have one and so let me just try writing a 16 down so now that's a balanced equation so we could go through 16 silver 16 silver eight sulfur eight sulfur and that's going to be be a balanced equation the nice thing about balancing equations is you can always check it at the end and you know that you are right it's not like you're maybe right you absolutely are right as long as you're just adding the coefficients all right so here's the ones that are more likely that you're going to find and so let's work through this and always be patient remembering that if you get frustrated you can just erase them all start over again you should be able to figure them all out it's just kind of a guess and Che but let me show you how I would think this one out so we've got water carbon dioxide got a hydrocarbon here and then we've got an oxygen and so on the right side the thing that jumps out to me right away is we've got seven carbons on the right side and so what I'm going to try to do is put a seven over here okay so what does that do for me now I've got my seven carbons taken care of um the other thing that jumps out right away is on the right side I have eight hydrogens and water is the only thing on the left side that actually has hydrogens and so if there's an eight here let me try putting a four over here okay so what that does is give me hydrogen on the left is going to give me eight hydrogen on the right side is going to give me eight as well now I love it when I solve these and I get down to just like one thing left and it has one atom in it and so I think carbons and hydrogens are good on either side but let me take a look at the oxygens on the left side we have four oxygens so in this molecule of four Waters and then we have 14 here and so I've got 14 total oxygen seven here and then four over here and so how do I get to so I again I've got 18 total and so if I were to put a nine over here that would give me on the right side 18 total oxygens on the left side totally Ox uh uh 18 total oxygen as well so that would be a perfectly balanced equation and so that's kind of my starters guide on how to balance equations um remember you can only add the coefficients you can ever change the subscripts and uh and if you can get confused start imagining them as molecules and and even draw them out if you have to and that might help a little bit so uh I hope that's helpful and uh have a great day