in this video we're going to talk about how to write net ionic equations so let's consider the reaction between aqueous lead to nitrate and aqueous potassium chloride now the first thing that you need to do is you need to predict the products of this chemical reaction that's the first thing now what we have here is a double replacement reaction lead is going to pair up with chlorine and potassium is going to pair up with nitrate potassium has a positive one charge nitrate has a negative one charge if the magnitude of the charges are the same then you can combine those ions in a one-to-one ratio so one of the products will be kno3 now the other product we need to pair up lead and chloride lead has a positive two charge and we could tell based on how many nitrate ions are attached to it each nitrate ion has a minus one charge and there's two of them so to neutralize the two nitrate ions lead has to have a positive two charge chloride has a minus one charge so when you combine these two it's going to be lead 1 cl2 or basically just pb cl2 now we need to write the phases of the products potassium nitrate is it soluble or insoluble so hopefully you're familiar with your solubility rules nitrates are always soluble so therefore this is going to be an aqueous phase now what about lead to chloride does that dissolve in water or is it insoluble in water lead to chloride is insoluble the halides chloride bromide iodide they're soluble with everything except lead silver and mercury so what we have here is a solid product now our next step is to balance the formula equation that we have here so notice that we have two nitrate ions on the left side so therefore we need to put a 2 in front of kno3 but now we have two potassium atoms on the right side so we got to put a 2 in front of kcl and we could put a 1 in front of the other ones so now we have a balanced formula equation now whenever you mix two aqueous solutions and if you get a solid product then this reaction is not only a double replacement reaction but it's also called a precipitation reaction so keep that in mind now once we have our balanced formula equation we need to write the total ionic equation and the way to do that is to you need to identify every substance that is in the aqueous phase and separate them into ions the substance that is in a solid or liquid phase or anything else other than aqueous phase you want to rewrite it exactly the way it is so let's do nitrate we're going to have to decompose it into ions so we have a pb plus two ion and two nitrate ions next we need to break up kcl so we're gonna have two potassium plus ions and two chloride ions and then potassium nitrate is also an aqueous phase so that's two k plus plus two no3 and this we're not going to change it we're just going to rewrite it as pb cl2 in the solid phase all of the ions that are listed here they are in the aqueous phase so you can write aq for all of them if you want to now the next step that we need to do is we need to eliminate the spec to the ions what are the spectator ions in the total ionic equation can you identify the spectral ions are those that appear exactly the same on both sides so potassium is a spectator ion nitrate is a respected ion now what you have left over is the net ionic equation so it's lead 2 plus by the way if you're doing one of those online homework assignments you may have to write pb as two plus instead of plus two i don't know if they're going to change it in time but when i remember doing these questions for like an online assignment you have to write it as two plus instead of plus two so if you see me writing s plus two it's just a habit of mines but you may have to your teacher may want you to write it as two plus so just keep that in mind so we also have two chloride ions and this is going to form pb cl2 solid so this here is the net ionic equation of this precipitation reaction so as long as you follow the process these problems won't be that difficult you just gotta do a few practice problems on it and you'll get that you're gonna get the hang of it let's try another example this time it's going to be an acid-base reaction so we have aqueous sulfuric acid reacting with aqueous sodium hydroxide predictive products of this reaction balance the formula equation write the total ionic equation and then the net ionic equation and also identify the spectrons feel free to pause the video if you want to try this so this is another double replacement reaction it's also called an acid-base neutralization reaction now just like the last example we're going to pair up the first part with the last part and the two parts in the middle the sodium and the sulfate ions will get together now whenever you mix hydrogen with hydroxide it will always create h2o so in any strong acid strong base neutralization reaction you're always going to get water as a product and water is in a liquid state now what about pairing up sodium and sulfate what is the chemical formula of sodium sulfate sodium is an alkali metal in group one sulfate is a polyatomic ion with a negative two charge so to write the formula is going to be na2so4 so that's sodium sulfate now go ahead and balance the chemical reaction so how can we balance this reaction well for one thing we have two sodium atoms on the right side so we got to put a 2 in front of naoh and now notice that we have a total of four hydrogen atoms two from naoh and two from sulfuric acid so therefore to balance the hydrogen atoms we need a two in front of water and so now the chemical reaction is balanced sodium sulfate is it soluble or insoluble all of the alkali metals found in group one are soluble so this is an aqueous phase so now we can write the total ionic equation so keep in mind in order to do this everything that's in the aqueous phase will need to separate into ions so let's start with sulfuric acid it has two hydrogen ions and one sulfate ion next let's move on to sodium hydroxide so we have two sodium ions don't forget there's a two in front and two hydroxide ions now let's move on to sodium sulfate there's two sodium ions and one sulfate ion so all of these ions keep in mind are in the aqueous phase so you gotta write aq for each one now water is not an aqueous phase it's a liquid so therefore we're not going to separate it into ions we're just going to leave it like this so this is the total ionic equation now what are the specter ions in this example what ions appear to be the same on both sides of this equation well we have the sodium ions they appear exactly the same and also the sulfate ions so what we have left over is 2h plus plus o h which produces two water molecules now notice that we could divide everything by two we can reduce the coefficients and if you can you should so the balance net ionic equation it's going to be h plus plus oh minus produces one water molecule so h plus is in the aqueous phase hydroxide is in the aqueous phase and water is in the liquid phase so this is our balanced net ionic equation so hopefully these two examples will help you to write net ionic equations for any double replacement reaction so that's it for this video thanks for watching and if you want to find more of my chemistry videos just feel free to check out my channel you can find chemistry tutorials physics calculus algebra and a lot of common subjects that are taught in high school and in college so thanks for watching you