in this video we're going to talk about types of chemical reactions synthesis reactions decomposition reactions combustion reactions and then single and double replacement reactions so what is a synthesis reaction this is a reaction where you have multiple reactants combining to form a single product so a plus b turns into a b let me give you some examples so if we take zinc metal and react it with oxygen gas this is going to turn into a single product zinc oxide now this reaction is not balanced and we really don't need to do it for the sake of this video but notice that we have two smaller components and we're generating a single product that is a synthesis reaction which is also called a combination reaction zinc and oxygen are pure elements zinc oxide that's a compound it's made up of two different elements here's another example if we were to take barium oxide which is a compound and react it with carbon dioxide which is another compound this will give us a single product at low temperatures known as barium carbonate this is also a synthesis or combination reaction because we're taking two smaller components and combining it into a larger product or a single product so that's the basic idea behind a synthesis reaction now before we go into the next type of reaction i do want to mention for those of you who are watching my videos and who haven't subscribed yet feel free to take a minute hit that subscribe button and don't forget to click on that notification bell that will be greatly appreciated now let's get back to this video decomposition reactions a decomposition reaction is the reverse of a synthesis or combination reaction so in this case you're starting with a single reactant a b and you're going to break it up into two or more products typically a plus b so a good example of this is magnesium nitride so this is an ionic compound and when heated will decompose into its component elements magnesium and nitrogen gas so here we have a single product breaking down into multiple fragments so that is a decomposition reaction another example is the use of calcium carbonate if you heat up calcium carbonate you can represent the heat phase with uh i mean the word heat with a triangle if you heat up calcium carbonate it's going to decompose into calcium oxide and gaseous carbon dioxide so that's another example of a decomposition reaction it's simply the reverse of a synthesis reaction the third type of reaction that we need to talk about is a combustion reaction combustion reactions typically involve some compound containing carbon hydrogen and or oxygen and typically the most common example of these reactions is that you take that compound react it with oxygen gas and you're going to get two products carbon dioxide and water so here's an example of one propane c3h8 reacts with oxygen gas to produce gaseous carbon dioxide and liquid water depend on the temperature if the temperature is above 100 that's going to be steam so we'll put h2o with a gaseous phase another example would be ethanol c2h5oh so this is an example of a compound containing carbon hydrogen and oxygen when ethanol reacts with oxygen gas it too can create carbon dioxide and water assuming there is sufficient oxygen gas to react with it in the first place otherwise carbon monoxide could be created as well which is not a good gas to deal with but with sufficient oxygen gas this reaction will go to completion and you'll get carbon dioxide and water so those are examples of combustion reactions combustion reactions are very exothermic which means they release a lot of thermal energy when you react gasoline with oxygen let's say in a combustion engine it will generate a lot of energy a lot of heat energy and some of that energy is used to power the car to make it move forward and so combustion reactions are very useful in terms of everyday applications now let's move on to the next type of reaction that we need to consider and that is single replacement reactions in a single replacement reaction you have the general formula a plus bc turns into ac plus b so what happens is in this example a displaces b out of the compound and so b leaves it's now by itself so let me give you an example in this case for this type of chemical reaction you're going to have a metal displacing another metal out of a compound so zinc metal reacts with copper chloride that is aqueous copper chloride which means it's dissolving water to produce aqueous zinc chloride plus copper metal so notice that zinc displace copper out of the solution so now zinc is in the solution copper is now a metal a solid metal that is not dissolved in the solution anymore and so that is a single replacement reaction zinc replaced copper out of the solution or kicked it out of the solution if you want to say that now there's another type of single replacement reaction in this example we considered a metal replacing another metal you can also have the situation where a non-metal replaces another nonmetal the general reaction for this type of situation is going to be a plus bc and that's going to turn into ba plus c so in this example a let me use a different color a is going to displace c out of the solution so here's an example let's say we have a liquid bromine in its elemental form and we're going to react that with a solution of sodium iodide in this reaction notice that bromine and iodine or in this case it's in the form of known as iodide both of these are non-metals bromine and iodine are they're not metallic so bromine is not going to displace sodium because sodium is a metal bromine is going to displace another non-metal like itself in this case iodine so we're going to get is sodium bromide which is an aqueous form plus elementor iodine which is a solid so in this case we have a non-metal displacing another nonmetal out of the solution that's the second type of situation that you'll see when dealing with a single replacement reaction now the next type of reaction we need to consider is a double replacement reaction in this reaction we have a b reacting with cd now what are the products that you think we're going to get and notice the keyword double replacement the two middle ones will come together that's b and c but it's going to be written as cb not bc and the one the two parts that are on the outside they're going to pair up together and it's going to produce a d so those are the products of a double replacement reaction let me give an example aqueous calcium chloride reacts with aqueous sodium nitrate to produce aqueous calcium nitrate plus aqueous sodium chloride so this is an example of a double replacement reaction we can see that calcium paired up with nitrate in this case this would be ad i have them switched around for some reason and uh sodium paired up with chlorine as we can see nacl so notice that na is written first this is actually cb cl is written later if you break this up into ions you'll have calcium two plus you have the chloride ion na plus and the nitrate ion notice that the positive ions are written first so that's why sodium is written before chloride because it has the positive charge calcium doesn't want to pair up with sodium because like charges repel that's why calcium pairs up with nitrate because they're opposite charges calcium has a two plus charge nitrate has a minus one charge ions with opposite charges will attract each other and that's why sodium is attracted to chloride because they have opposite charges so you shouldn't see calcium paired up with sodium they have the same charge that's not going to happen and you shouldn't see chloride paired up with nitrate that's not going to be correct now there are some other types of displacement reactions or rather double replacement reactions that you need to be familiar and some of these have special names consider this one let's say if we react calcium nitrate with sodium phosphate both of these compounds are in the aqueous phase which means they dissolve in water they're water soluble now this is going to produce sodium nitrate which also dissolves in water plus calcium phosphate now calcium phosphate is not water soluble it is insoluble in water which means it doesn't dissolve in water now this reaction will be visible the other reaction is not visible because everything was in the aqueous phase but for this one notice that we get a solid product whenever you mix two aqueous solutions and if it produces a solid product then the double replacement reaction has another name and that name is a precipitation reaction calcium phosphate precipitated out of the solution so this is an example of a precipitation reaction you may learn this later if you haven't learned it already but at least now you know what it is here's another one if we take sodium sulfide in its aqueous phase and react it with hydrochloric acid this is going to create sodium chloride which will also be an aqueous phase but we'll also get something at excuse me something else h2s hydrosulfuric acid and this is a gas so notice that not everything is in the aqueous phase we're mixing two aqueous solutions and we're getting not a solid product but a gaseous product so this type of reaction even though it is a double replacement reaction sodium paired up with chlorine hydrogen paired up with sulfur even though it's a double replacement reaction it's it also has another name and that name is known as a gas evolution reaction because a gas evolved out of the solution so that is a gas evolution reaction another type of double replacement reaction and for those of you who are curious there is another type of double replacement reaction and here it is let's say we react hydrochloric acid with sodium hydroxide in this example sodium will pair up with chlorine forming table salt sodium chloride and then hydrogen is going to pair up with hydroxide forming water now water is not a solid it's not a gas but it's a liquid so what do you call this this is still a double replacement reaction but it also has another name and the name for this reaction is an acid base neutralization reaction why is it called that well hcl is an acid hydrochloric acid sodium hydroxide is a very strong base whenever you mix an acid and a base specifically a strong acid and a strong base they will neutralize each other creating salt and water and that's all folks that is the end of this lesson so for those of you who found it to be helpful and uh very informative make sure to hit that subscribe button double tap it if you have to and uh click on that notification bell so thanks again for watching and i'll see you hopefully in the next video