here we're going to practice classifying chemical reactions we're going to look at a whole bunch of them and we're going to figure out what type they are now if this stuff here looks unfamiliar to you and you need some background check out my introductory video on this topic and then come back and we'll do these problems so here are the five major types of chemical reactions for each I've written a sort of General generic example equation that shows what the reaction looks like now just a heads up the equations that we'll be using in this lesson are unbalanced because for right now I just want you to focus on the elements and how they're rearranging and I don't want you to worry about getting distracted by the coefficients okay so let's start classifying reactions here's our first magnesium and aluminum chloride give us aluminum and magnesium chloride so what's happening here we have aluminum and chloride paired up here magnesium is on its own and then magnesium comes and takes the place of aluminum magnesium pairs up with chloride and kicks aluminum out so when something like this happens we're talking about a single replacement also known as a single displacement reaction C8 h18 which is the chemical formula for Octane and oxygen gives us water H2O and CO2 so whenever we have something with carbon and hydrogen and we add oxygen to it and we get water and carbon dioxide that is a combustion reaction so this shows us the combustion of octane which is one of the components of gas magnesium chloride turns to magnesium and chlorine gas What's Happening Here is a compound is breaking down into simpler components this is a great example of a decomposition reaction magnesium and oxygen combined to give magnesium oxide so what we have here is we have two simple things coming together to make something more complex which is what happens in a synthesis reaction so this is a synthesis of magnesium oxide now just real quick I'm referring to this chart to help classify the reactions but chances are you wouldn't be allowed to use one like this on a quiz or a test okay so just make sure that you really learn these sample uh equations for each reaction so that you're totally good with this when you run into it on an exam or something silver nitrate plus sodium chloride give us silver chloride and sodium nitrate what's going on here well we have two pairs that then switch their Partners silver was initially paired up with nitrate and then silver ends up pairing up with chloride over here and sodium was initially paired up with chloride and then sodium ends and switches up here with nitrate so this where we have two pairs switching Partners is a really good example of a double replacement reaction sodium carbonate turns into sodium oxide and carbon dioxide so here we have a compound breaking down into simpler compounds this is what happens in a decomposition reaction now in this decomposition reaction we don't see this compound breaking all the way down to the elements that make it up we're not getting just sodium carbon and oxygen but it's breaking down into simpler compounds that themselves are still combinations of more than one element but that's okay it's still a decomposition reaction just as long as we have something complex breaking into simpler pieces zinc by itself and HCL which is called hydrochloric acid give us zinc chloride and hydrogen gas so what's happening here we'll look at what's paired up together hydrogen and chloride here are paired up and then zinc by itself pushes that hydrogen out of the way and ends up pairing up with chloride giving us hydrogen by itself self so when this happens when an element on its own kicks out another element and takes its place in a pair that is a great example of a single replacement reaction sodium chloride and h2so4 known as sulfuric acid come together to give us sodium sulfate and HCL hydrochloric acid so what's happening here is that we have two pairs of two different things we got Na and Cl and H and S so4 they switch places so the na that used to be paired up with the CL ends up pairing up with the S so4 and the H that was initially paired up with the s so4 ends up paired up with the CL so this is an example here of a double replacement a double replacement reaction okay here's the last one C6 h126 which is the chemical formula for glucose it's a sugar and food that you eat glucose combines with oxygen to give us carbon dioxide and water all right this should look pretty familiar when we have something with carbon hydrogen and sometimes oxygen and we combine it with oxygen we get CO2 and H2O that is an example of a combustion reaction and this is a great combustion reaction to look at too because this is one of the examples where what we're burning what we're combusting doesn't just have carbon and hydrogen in it but it also has oxygen remember that it's also possible to burn or combust things that have carbon hydrogen and and oxygen in them as well the rest of the combustion reaction looks pretty much exactly like it does when you have something with only carbon and hydrogen so those are a whole bunch of practice problems for classifying these chemical reactions if you can work through these if you learn these different example equations you should probably be totally fine