So, we've talked about some reactions you're responsible for predicting, such as a double displacement reaction or a combustion reaction. What we want to expand on this a little bit for some other reactions you're also responsible for. The first one we're going to talk about is a double displacement gas production reaction. So, what this is is it's a neutralization reaction. So something happens but the product it produces the product itself will rearrange those ions in solution and then form a gas and water and so the the um dissolved ions again they immediately rearrange in solution. If the unstable compound is formed it will decompose to form a gas and you see this when you mix like vinegar with baking soda. Vinegar is acetic acid. Baking soda is sodium bicarbonate. In so in solution you have vinegar which is a weak acid. So you have some acetic acid floating around. You have some acetate floating around and you have some H+ floating around. And then baking soda is sodium bicarbonate. So you have Na+ floating around and you have bicarbonate floating around. Well, what's going to happen is that your acetate and your sodium stay spectators. these quote unquote pair up when we write the reaction. But these are your spectators. When that proton from the acetic acid finds the bicarbonate from your baking soda, these pair up and they form H2O3. But if anyone's ever mixed baking soda and vinegar, they know that they also see bubbles. And that's because what happens here is this decomposes to form water and CO2 gas. And it's the CO2 gas that's causing those bubbles. Anytime you guys see the formation of H2 CO3, it is going to form water and CO2. Anytime you guys see the formation of H2SO3, it's going to form water and SO2. And if you see the formation of ammonium hydroxide and H40, it's going to form water and NH3. You have to memorize these. Okay. So again, these products on this side come from that double displacement reaction that we've talked about previously and we'll see more examples of. If you see H2 CL3, carbonic acid, H2SO3, NH40. If you see these things forming, they form water and then whatever is left over is the gas. So for H2 CO3, you've got CO2 left over. For H2SO3, you've got SO2 left over. For NH40, you've got NH3 or ammonia gas left over. And you have to recognize these. So, let's work out some examples here. First up, we have calcium carbonate reacting with hydrochloric acid. You need to know your compounds at this point. You need to be able to do your polyatomics, know your names, and be able to put these together. You guys should know that calcium carbonate is Ca3. Now by solubility rules I know that carbonates do not like to be soluble and calcium carbonate is actually a solid but this will react with hydrochloric acid. Hydrochloric acid is HCl and the reason it will react is the HCl will can react with the car um calcium carbonate. So even though it's in a solid phase it will react. This is a double displacement reaction. So when it reacts it's the cation of one with the anine of the other. So, Ca2 is formed that is aquous solubility rules and then the cation of one with the annion of the other and that forms H2 CO3. Now, I do have to balance this in a sec, but that is aquous and then we have to recognize it is a double displacement reaction. So, a couple different things going on here. First, let's balance it. I need two chlorines on both sides. So, I put a two in front of the HCl. That also balances out my hydrogen. So, I have the right amount on both sides. But when I see this product, I need to recognize that that further decomposes. So the actual products to this reaction are still the Ca2 that is a product. Yes. But then I'm also going to form water and CO2 gas phase. So again calcium carbonate reacted with two moles of HCl. And what we originally write down is calcium chloride and H2 CO3 as the product. But we recognize that H2 CO3 further decomposes. So I still have that calcium chloride, but now I've also produced water and CO2 gas. Let's do that with our next example. Ammonium nitrate and sodium hydroxide. Ammonium nitrate. Ammonium is NH4 plus. Nitrate is NO3 minus. So it's a 1:1 ratio here. Ammonium salts always soluble. Nitrate salts always soluble. Sodium hydroxide is one of my strong bases. So, it is always soluble. And I'm going to swap partners here. Cine of one to anion of the other gives me NH40. Cine of one to annion of the other gives me NaNo 3. Again, sodium group one salt always soluble. Nitrate always soluble. So, it's all soluble here because it's all soluble. This reaction, if it had actually stopped here, if it didn't produce a gas, would be no reaction because everything in the solution is aquous. There's no reaction. But that's not quite true in this example because this further decomposes. So again, what I mean by this is if I have all these in a beaker together, I have ammonium ions, I have nitrate ions, I have sodium ions, and I have hydroxide ions. Okay, so they're all floating around. These stay spectators. These though are soluble in solution. So, as written, it would look like no reaction except these two will pair up and form more water that's already in solution and then some ammonia gas. So, I need to be able to recognize that and write that out as well. So, that's going to form ammonia gas and water and sodium nitrate is my spectators. So, they stay aquous. Now again if you don't remember what the products are, you have to recognize H2 CO3 and H40 and soon we will see um H2SO3 doing this. Yes. But if you get confused what the products are, remember it is water and whatever's left. So what I mean by that is if I have H2 CL3 and I take away the water. So I've taken away two of the hydrogens. Oops, sorry. Taken away two of the hydrogens and one of the oxygens. I'm left with CO2. If I have NH40 and I take away water, I've taken away two of the hydrogens and one of the and the one oxygen. I'm left with NH2, which is the same as NH3. And the same thing for the H2SO3. If I pull water out of here, I got rid of my hydrogen's and one of my oxygens. I've got SO2 left over. So now, yes, I just know them. But when I was first learning them, I did them by remembering I had to produce water and gas. And that was the way my brain kept it straight in my head easier. Okay, let's do the last one. Sodium sulfate plus hydrochloric acid. So or sorry sulfite not sulfate sulfite sodium sulfite Na2 SO3 sodium salts are always soluble so this is aquous and HCl hydrochloric acid is a strong acid so it is soluble of one to annion of the other forms NaCCl which is aquous all sodium salts are aquous of one to Nion of the other forms H2 SO3. Now balance it. I have two sodiums on the reactant side. So I need two on the product side. That gives me two chlorines, two chlorines, and now my hydrogen's are balanced as well. But again, I need to recognize that this is one of the those three that I have to pay attention for and watch for that will further decompose. forming water SO2 gas and then my NaCCl aquous which is my spectators. So the driving force of these reactions is the formation of H2O and CO2 H2O and NH3 H2O and SO2 the formation of water and gas is the driving force of the reaction. You're also responsible for single displacement reactions. In a single displacement reaction, a more active element replaces a less active element. So for example, aquous copper 2 sulfate plus iron. Aquous copper 2 sulfate. Copper 2 sulfate is CUSO4. Aquous means dissolved in water. And I mix this with iron. Iron pieces just means iron solid. What this is going to do is it's going to give me Fe SO4 aquous. So iron 2 sulfate aquous. and I can pull out copper metal from it. It's a single replacement reaction because the iron replaced the copper. Notice here the cation is replaced by another species that can form a cation which is a metal. So the metal cation was replaced by a metal which formed a cation. Okay. So cation replaces cation. The second example we're going to do here. Florine gas F2 reacts the solution of potassium chloride. Potassium is a um group one salt. So always soluble. This is going to form KF aquous and Cl2 gas. Now I do have to balance this reaction. So I need a two here and a two here. But notice here the annion which came from a non-metal was replaced by another species forming an annion. So another non-metal And you have to pay attention to your diatomics here. A metal replaces a metal ion in a compound. You are not responsible for predicting which metal will lose electrons easiest. It will be obvious from the question. We learned this in Chem 2. Okay? If I tell you this reaction is happening, then they have to replace. That's how you know. A non-metal though will replace the nonmetal in a compound, which is what we see in part two or in part B. This one you are responsible for a little bit of it though. The H hallogens play king of the mountain. The one with the largest electron affinity which is the top of the table will steal electrons from the groups below. What that means is that florine wins over chlorine. Chlorine wins over bromine. Bromine wins over iodine. So F2 Cl2 Br2 I2. Okay. F2 will form F minus before um over CL over Br over I. So if you have something lower on the table, it's going to give up its electrons forming its diatomic, which is what I see here with the chlorine. The chlorine is lower on the table than florine. So the chlorine gave up its electrons for florine to form an F minus. F2 accepted them to be able to form the F minus. So the electrons are transferred, oxidation states are changed. These are redux reactions. All of these are redux reactions. Metals replacing metals, nonmetals replacing nonmetals are redux reactions. For the metals, I will make it obvious which ones being replaced. As written here, aquous copper sulfate with iron pieces. The reaction is going to happen. I won't give you one where it doesn't happen. With the nonmetals though, you do have to recognize if it will happen or not. So if I had written something say I had written um if I had written like Br2 plus 2 KCL what's going to happen that is no reaction because Br2 is lower on the table periodic table than chlorine it's further down the table. So therefore there will be no reaction. The bromine cannot pull those electrons away. Bromine cannot oxidize the chlorine to steal its electrons and so that would be no reaction. And we will actually learn the tables in Chem 2 where you can see the numbers that back up this work. But right now you just have to know this part. Okay. What about metallic and nonmetallic species in water? They form in hydrides. So they do two different things. Non-metal oxides. So yeah, metallic and nonmetallic oxides plus water. Non- metallics form acids. Metallics form bases. So it does need to be a non- metallic oxide means a non-metal with an oxygen. Metallic oxide means a metal with oxygen. A non-metal plus oxygen will form an acid. And here we see sulfur dioxide. So SO2 that is a gas. It reacts with water and it forms H2SO3. Now some of you may realize that we just talked about this reaction and said, "But if we form H2SO3, it's going to form water and SO2." And you are right. It is an equilibrium reaction. It goes back and forth. It does both. So if you are writing it as H2SO3 is the product of a double displacement reaction, you then tell me it further breaks down into water and SO2. But if I'm reacting sulfur dioxide and water, you're going to tell me it's going to form H2SO3. It is forming an acid. We've got magnesium oxide plus water. Magnesium oxide is also a solid. And if I mix that with water, that forms magnesium hydroxide, which is one of our weak bases. So non- metallic oxides, a non-metal with an oxygen forms an acid. Metallic oxides, a metal with an oxygen forms a base. The way I remembered this on the peric table because I remember a lot of things from that table itself is if you think about the peric table construction kind of okay kind of ignoring the flock all the time but remember your non-metals are basically over Your metals are basically everything else. But remember, let me move right about that. Your bases are also right here. Your acids come from over here. Like your strong bases are over here. Your strong acids come from this side of the table. So, it makes sense to me that my non-metal oxides will form those acids because that's where acids are formed anyway. and my not my metals with um water will form bases because that's where they're coming anyway. That or you could think about it from the fact that acids have to have H+ plus an annion and non-metals form annions. Bases are hydroxide plus a cation which we usually well we write your cation first. So cation plus hydroxide is a base and the cations ions come from your metals with the exception of a couple polyatomics. Combustion reactions you should be pretty comfortable with at this point. You are responsible for hydrocarbons and alcohols. Hydrocarbon means carbon hydrogen containing compounds only. So if I had CH4 reacting with oxygen, CH4 is called methane. I've got CH4 gas, O2 gas. This always forms CO2 and water. No exceptions to that rule. Then you just have to balance it. We have one carbon on each side. We need four hydrogens. So we put a two in front of the hydrogen here. That gives me four oxygen on the re on the product side. So I need four oxygen on the reactant side. And alcohols mean carbon, hydrogen, oxygen containing compounds. This is what you are responsible for. And so it's got here ethanol which is the alcohol that people consume. We've got C2 H5O liquid reacting with O2. It still forms CO2 and water. That has not changed. When I go ahead and balance this out though, we've done this one before, but you've got two carbons, two carbons, six hydrogen. Do not forget the hydrogen right there. Um, six hydrogen. This gives you seven oxygen on this side, which is an odd number. So, I recommend doing the fraction and then undoing the fraction. Two, 7, 4, and six. You also have synthesis reactions. A synthesis reaction is where a compound is synthesized. Hence the word synthesis, which means prepared or produced. from two elements. So like sodium plus chlorine, sodium and a solid chlorine Cl2 gas. When these react, they form NaCl. Now I do have to balance this. I need to put a two in front of here because of the chlorines and a two for the sodiums. But two things went in. They made one thing. Not all synthesis are two in two in one out but the ones you guys are responsible for are two in one out. Aluminum pellets react with liquid bromine. Aluminum is a solid. Pellets is just telling you a phase or tell telling you a shape of it. But aluminum is a solid. This reacts with Br2 which is a liquid. It's one of the only two liquids on the table at room temperature. And I know that aluminum bromide can form. Need to balance this thing. I've got that 23 ratio going on with my broines. So I'm going to put a three there and a two there. Put a two in front of my aluminum. So notice here, metals are losers. They're going to lose electrons to form cations. Non-metals form annions by gaining electrons. Electrons are transferred. Oxidation states are changed. These are redux reactions. A lot of the reactions you do are redux reactions. Decomposition. Most compounds decompose to form a gas. O2, CO2, SO2, water, and a leftover compound could have heat, um, electrolysis or catalyst. And this is often necessary for the reaction to happen. So, often times I have to heat the reaction. Electrolysis is where you apply electricity from an outside source. um a catalyst and we will talk more about electrolysis and catalyst and chem 2 but you need to recognize the trends here and you should also recognize which ones are redux reactions. So first up we have copper hydroxide or copper 2 hydroxide. Copper 2 hydroxide is Cu2. This will decompose to form copper oxide and H2O gas. How do you know if it's a redux reaction? You look at the oxidation numbers. Copper started off as +2 because it's copper 2. Hydroxide is O minus. So the oxygen is a -2. The hydrogen is a plus one. Giving the overall component a negative 1. Copper state plus2 oxygen -2. Hydrogen + one. Oxygen -2. It's not reduxed. potassium chlorate KL3. This will decompose into potassium hypocchlorite. Forgot the C in there and O2 gas. Check your species. Potassium is a plus one. It's easiest if you split these up into their separate parts. Okay, plus and CL3 minus to answer it. Okay, Cl3 minus. The oxygen are -2 the overall and there's three of them. So overall -6. The species needs a negative 1 charge. So my chlorine must be a + 5. So plus five on my chlorine, -2 on my oxygen. For the KCl though, potassium is still + one. But notice that this is Cl minus now, which means my oxygen is still -2, but now my chlorine can only be + one. And my oxygen here went to a state of zero. So this is a redux reaction. The chlorine has changed oxidation state going from + 5 to + one. So the chlorine gained electrons. O3 minus was reduced. It's the oxidizing agent in oxygen in the Kl3 or in the Cl3 minus you can um you can bring it down to the polyatomic. Don't bring it down further than that. This the um florine in here is reduced. The oxygen was oxidized. It lost electrons and it's a reducing agent as it went from a negative charge to a zero. It lost those electrons. And then we have copper 2 carbonate. Vu C3 carbonate is a -2 charge. Carbonates are usually solid and this is not an exception to that. And this will form copper 2 oxide and CO2 gas. So the copper stays the plus2 charge. Oxygen stays minus2. What does the carbon do? It's plus4 over here. Cl3 2 minus. Oxygen is overall -6. So the copper stays plus4. So this is not redux. Students al often freak out at this slide because they're like oh my god how am I going to know all this? I will give you help. I will not just throw you to the walls and say expect you to do all this. I will say things are produced or I will give you hints that are able to help you answer these questions. Okay let's keep going. Ammonium carbonate. Ammonium carbonate is NH42, CO3. This forms water, CO2 gas and NH3 gas. Two NH3, two moles of ammonia just to be balanced out. Carbonic acid, you guys should know this one. H2 CO3 goes to water and CO2. Sulfur is acid. You guys should know this one. H2SO3 goes to H2O liquid and SO2 gas. I'll do the um oxidation numbers in just a sec. hydrogen peroxide, H2O. Hydrogen peroxide is actually a liquid. It's very reactive. It's not a very stable compound. Forms H2 gas and O2 gas. So, I can tell you right now, this is a redux reaction. Hydrogen, oxygen go down to their zero states. Here, oxygen is a -2 and hydrogen is a plus one. Let's work backwards. and sulfur dioxide. Oxygen is a -2, so sulfur is a +4. And water, it's always -2 + 1. Okay, the hydrogen here is a + one. SO3 2 minus. My oxygen is -2. There's six of them overall, so my sulfur stays plus4. Not redux. um carbonic acid breaking down to water and CO2 -2 + 4 -2 + 1 + 1 C3 2 minus my oxygen is a -2 I have overall -6 charge or oxygen gives me6 charge I need overall -2 so carbon had to stay plus4 not redux and ammonium carbonate hydrogen will be + one doesn't I want to go negative. So + 1, which means nitrogen is a -3 -2 + 4 -2 + 1. Cl3 2 minus I know we figured that out below, but to rewrite it, -2 over all the oxygen are -6. I need overall -2. So carbon has to be a plus4. NH4 plus each hydrogen is plus one I mean overall plus one charge and it's um hydrogen overall adds up to plus4 so the nitrogen has to be3 so this is also not redux so you can see when I form things like oops wrong button H2 gas O2 gas I get a redux reaction when I form things like O2 gas, it was a redux reaction. So if you're forming a base gas, you're getting that redux reaction.