 Howdy say on fleeting science. We're going to be looking at balancing equations very simply So we're going to start by using a method I call the shopping bag method and then after that we're going to try it without So this is the equation. We're going to balance sort of a hydrogen and chlorine reacting to produce hydrochloric acid We're going to use apples to represent hydrogen atoms and bananas to represent chlorine atoms What we're going to do is we're going to follow one of the fundamental rules is Basically, you can change the number of molecules you have but you can't change what makes up the molecule and the way we do that When we're doing this example is we can change the number of shopping bags that we have but not what's in a shopping bag so Have a look at our what out what we have so we've got apples representing hydrogen atoms chlorine is being represented by bananas if you see a little number after Something that means you have that many of whatever's in front so in this case I have two hydrogens and two chlorines, so I need to represent that in my shopping bags So in this shopping bag, I've got my hydrogens In this shopping bag, I've got my chlorine so I have to have two of them There we go And over here. I've got one apple one hydrogen and one banana one chlorine So this is what I have once you represented it that way. It's a good idea to count up what you've got So if we have a look at our bags here, we can see we've got two apples here Two bananas here and only one banana and one apple so the question is is that balanced? We look at either side of the arrow So on this side of our arrow, we've got two apples on this side We've only got one on this side. We've got two bananas on that side. We've only got one So now what we need to do is figure out a way that we can get the number of bananas and apples to be the same on Both sides we can do that by changing the number of shopping bags Okay, so if we look here, how could we do it if we made a duplicate of that and how to look at what we have now Now if I have a look on this side, I've got two apples on this side I've got two apples in total now, so I've doubled the number of molecules of hydrochloric acid. That's what I've done So if I have a look at the number of bananas here, I've got two bananas and now on this side I've got two bananas So if we represent that by counting it up We've got two apples two apples two bananas two bananas on either side of the arrow now and balance When we're changing the equation at the top what we do is we put a little number two up front That means you have that number of everything that follows So we're over here you have a small number behind that means you have that of what's directly in front Over here what that means is you've got two of whatever is after it So in this case, we've got two hydrochloric acid molecules Now I've left spaces here to put ones, but we don't put one so we just say H2 plus Cl2 So now this is balance two apples two hydrogen atoms two chlorines two chlorine atoms on this side two apples two hydrogen atoms and Two bananas two chlorine atoms, so the big number out the front means we have that many of everything that follows