all right you guys let's go ahead and get started we got a lot to cover today first we'll start with announcements um so this week we'll have Quiz Number Nine which is going to be um over experiment 11 so in lab we're going to finish experiment 8 so if you didn't complete your fractional distillation last week you'll be completing that in lab this week and then we're going to also complete do you have a question I'm going to cover that in a little bit here just hang on just a sec so um so while we're there uh experiment 10 is just talking about gas chromatography so the what you're doing in lab this week is experiment 11 so that's why it's mainly over experiment 11 although there could be a couple questions about gas chromatography too but the doing in lab is experiment 11 so in in lab we'll finish experiment 8 we'll do the fractional distillation for experiment 8 if you didn't complete that last week which most of you did not um we'll need to collect some data for our experiment 8 um product and then we'll get we're going to use our experiment 8 product that we just purified and um complete experiment 11 with it so the preab needs to be over experiment 11 that is the basic doing in lab this week is experiment 11 and then the experiment 10 is information and background about gas chromatography which we will cover here in a little bit um so make sure you have your experiment 11 pre- elaborated to go remember all the parts so you're now responsible for everything that including the flow diagram there's not a flow diagram we give you this week so you've got to put all the parts together for your own preab and remember you're using experiment 's product so experiment 11's prelab should reflect using experiment 's product and then um what the what products you would get from that okay the um this week your experiment 7 report is due that's where 75 points um so make sure you have that ready to go at 75 points because it's was a weaker with three three um reactions in it uh next week we'll have quiz 10 and it says that we're doing experiments 12 and 13 so experiment 12 is the what you're doing in lab Experiment 13 is the information for thin layer chromatography which we will cover next week um in lab lecture okay so the preab for experiment 12 needs to be in your notebook before you come to lab next week okay okay and then the report um for experiment 8 and 11 is due in a couple weeks either on Tuesday the 19th for the Tuesday Labs or Thursday the 21st for the um Thursday Labs okay here's all our reminders safety glasses dress appropriately bring your calculators clean up your balances big one because we had a lot of waste issues last week don't put any water in the organic waste no water goes in the organic waste it's only for organic waste magnesium salt sufate does not go in organic waste there are no carbons in mgso4 it is not organic it is inorganic it's a salt do not put it in the organic waste so make sure that you pay attention to to the proper waste disposal um I'm going to go over the we've seen this now two weeks in a row but I just want to mention it does appear that there potentially is an issue if you try and register of chem 256 AAP and chem2 6 BL lab some people are having trouble with it putting it in the schedule planner so then potentially putting it in your schedule if you have any issues with registering for both A and B um 256 lab chem 256 lab A and B um make sure that you contact the register's office if you are taking the BL lab you need to be registered for the a lab um and um if you are registered for the aab that sometimes causes conflict with the blab okay all right um let's go through things we need to know for experiment 8 before we dive into experiment 11 so everyone should be past the simple distillation of the ethylether this week that should have happened okay um you now need to be this week working on your fractional distillation with the Allin one your sidearm distillation apparatus is what you're going to be using for that fractional distillation you need to know the atmospheric boiling point of your alcohol okay so there were four alcohols that were made last week you either made three heptanol or four heptanol or you made three octanol or four octanol okay those are the four possibilities for the half sheets of paper that were handed out all right if you came up with some other structure you that is not correct okay so the three heol and four heptanol that boiling point range should be about 156 degrees um the three octanol and four octanol should be around the mid 70s those are the atmospheric boiling point ranges if you have something different than that then you don't have the atmospheric boiling point range okay so these are the ranges you need to know now for the fractional distillation you're going to collect three fractions there's a low boiling fraction you're going to collect up to 20 Dees below your boiling point range of your alcohol so if you have a heptanol you're going to collect up to the mid 130s if you you have an octanol you're going to collect up to the mid 150s okay then you're going to have a second um fraction that you collect from that 20 degrees below your boiling point range up to the expected boiling point range that is the second fraction and then the third fraction will be what you collect at the boil expected boiling point range of the alcohol so you want to collect all three of these fractions okay um is really again really important that you know what you made and you know what the boiling point range should be because you're basing all these colle um collection points off that boiling point range okay um make sure you hang on to all of these until you're absolutely certain you've got what you need most likely in the end this first fraction you won't need once once you're certain you have everything you need the other two you're going to hang on to and you're going to use for experiment 11 okay so um the first one the low boiling point fraction um or the low boiling fraction potentially you'll be discarding once you're certain you've got everything you need but the other two make sure you hang on to um you're going to collect the mass of your experiment 8 product you're going to prepare a GC sample so we'll talk about what's involved with that here in a little bit and then you need um oh here with the instructions with the GC sample um you need to make sure that it is dry so that's why we dried it with magnesium sulfate last week make sure it stays dry and there's no signs of water um and then you want to make sure there's no signs of solid that's present either water and or solid will clog up the GC column okay um you're going to add one drop of your experiment 8 alcohol to a GC vial so once you've made sure that it's dry and there's no solids present you can add one drop to GC V then you're going to fill to the neck with pentane so for GC we're using pentane as the solvent for GPC we use thf but for GC we're using pentan okay and then you're going to turn it into the sample block um and then fill out the sample signin sheet just like you did with your GPC sample um and then we will the lab props will get you back your GC data once once it is ready okay um you're also going to collect the IR spectrum for your experiment 8 um product so you want the mass you're making the GC sample and collect the IR spectrum these two things need to happen this week if you run out of time you could collect the IR spectrum at a different time but you need to have your GC sample before you leave lab this week because they're going to be immediately put on you actually need to prepare your GC sample for experiment 8 immediately after you collect the mass because I'm actually going to go around in the labs and be collecting the experiment eight samples as soon as they're ready okay so even before the lab period's over there's going to be so many GC samples that need to be run we need to make sure that we start running them as soon as possible so like tomorrow morning's lab as soon as the experiment 8 samples are all collected I'm going to put them on the GC before lab is even done if you need to collect your IR spectrum at a later date make sure you save a little bit of your purest fraction which is probably this third fraction so your GC sample and your IR spectrum should probably come from this third fraction which should be your purest fraction of of your product okay and then for the IR spectrum you're going to comp compare it to a literature um IR spectrum so if you made you know three octanol you but you can't find the IR for three octanol you could compare it to four octanol but you don't want to compare it to like one octanol okay so like three octanol and four octanol are both secondary alcohols you don't want to compare it to a primary alcohol okay um I in IR um in the IR Spectra um intermolecular forces um will change the Spectra so you want to make sure that you have a similar very similar compound you're comparing it to um and then you're going to put together an IR table like page 520 of the lab manual so this is what we used for experiment 6 on the report form this is what you should put together for for experiment 7 and then also for experiment 8 and then again for experiment 11 so that is all you you need to complete for experiment 8 then we're going to jump into um the elimination reaction for experiment 11 so what is involved there is we're going to take our alcohol it's going to be reacted with an acid okay and when it reacts with the acid we're going to form water which is a very good leaving group okay and so this this um type of elimination is called an E1 elimination reaction in that E1 elimination we end up forming a carbocation we form an intermediate so the E E2 elimination that you um used in forming styrene from bromo ethylbenzene um you didn't have an intermediate in an E1 elimination you do have an intermediate okay so react with the acid we lose um water as our leaving group and then that conjugate base of the acid can form an alken either in this case because this was a um two alcohol we could form it either um on the end or we could form it on this side of the carbocation so we could form either one heptin or we could form trans Andis two heptin depending on which proton was then um eliminated to form the alken okay and so in this case if this was what you were using you would probably see the mixture of um all of these alkenes with these being the predominant alkenes it's really important that you understand the mechanism we're getting into where you guys are drawing mechanisms in lecture so that means also in lab you are responsible for understanding mechanisms and being able to draw them so keep that in mind for lab this week um now one thing that can happen in this reaction is a carbocation rearrangement and that usually is going to be uh usually um happen if the conditions are favorable for it okay so in this case um when we have two methyl three heptanol three heptanol okay um or heptanol sorry um which will then form the Hep heptin um we have a secondary um position here where that carbocation is first made we can get a rearrangement to the tertiary position because remember tertiary is going to be more favorable or um more stabilized than a secondary position would be okay and so you can get that carbocation rearrangement all right and so um from the rearrangement we could then form the two methyl one heptin or if we don't rearrange then we could get the two methyl two heptin okay um depending well actually sorry from that rearrangement you would get get both of those okay um so just keep in mind with the carbo cation rearrangement you're rearranging to something more stable or something sometimes things that are equivalently stable but you're usually not going to rearrange backwards in stability okay you're not going to rearrange from something more stable to something less stable okay um and so zev's rule kind of goes hand inand with what just showed you the more St substituted the more stable alkenes will be the major product okay so if you can rearrange with a Carbo cadine to form a more substituted alken or more stable alken that usually will happen so um in our example the trans 2 heptin and the cy2 heptin is more favored than the one heptin now another thing that comes into play with alkenes is typically you're going to see more and um isomers then cyst isomers due to possible steric repulsion from the the cyst group so this is a um the cyst two heptin versus the trans two heptin um in our example you probably see more of the trans heptin um now for our reaction we're going to use sulfuric acid and there's specific reason for that when we look at sulfuric acid versus hydrochloric acid for this elimination reaction so for sulfuric acid um it's you know a strong acid that can be used um to uh promote you know to help protonate that um o group and help promote the formation of the alken so it's a good acid for protonating that alcohol and then it's conjugate base the hso4 minus is not really a great nucleophile which is good okay um and so what that does is it promotes elimination versus substitution so we will get more um elimination product than we would any substitution product if we had substitution product it would be the hso4 minus that would be doing the substituting but it's not a great nucleophile so it's not going to do that versus hydrochloric acid um our chloride ion is a good nucleophile so if we use that acid which would be a great acid for protonating the O group on the Alcohol it would also cause then substitution instead of purely just elimination okay so this is why we're using sulfuric acid versus hydrochloric acid for our reaction this week um now some precautions to think about for experiment 11 first of all we're using nine molar sric acid we used that last week when we did um the workup of the grenard reaction so it's the same nine m sulfuric acid so same precautions um apply it's just half dilute concentrated sulfuric acid so be careful handling it Pour it carefully um it's probably a good idea to wear gloves when you handle it and then also if there's any spills let's make sure they get cleaned up right away so no one Burns thems um from the spills um we are going to last week we just made a solution with the n m sulfuric acid that ended up being really cold this week we're going to heat up the sulfuric acid so we need to be more careful with that okay so it's going to be something that's very corrosive and now hot so we we need to take precautions with that um at the end of the experiment you're using the sulfuric acid in a distillation okay and so at the end of the experiment all this glasswar is going to be coated with sulfuric acid so you've got to be careful when you are going to clean things um not to drip it on you so as you take things apart carefully get them into your sink so you then can rinse them with water all right um so make sure the first thing you do is rinse all your glass wear with water after the distillation okay um the distillation pot so the remaining sulfuric acid um mixture that's going to be in the distillation part pot we're going to cool completely to room temperature and then we're going to take take your largest Beaker that you have in your drawer and you're going to fill it about 2/3 of the way with water and then you're going to carefully pour that the distillation pot into the water okay um and then that will carefully go down um the sink with lots of water okay so do not put it in the organic waste you do not put the sulfuric acid in the organic waste that can cause some um significant reactions with other things if you put um a lot of acid in the organic waste so this in this case this part goes down the sink but before that it goes into a large beak of water and then down the sink with lots of water all right for the steam distillation what is happening is water or in our case sulfuric acid in water in this experiment and an organic material so in our case our alcohols be coming an alken or a mixture of alkenes are going to distill out together okay so we're going to get this mixture this acid mixture with the alkenes are going to Cod distill together okay now the two components are IM missible from from each other even though they're going to distill over together they don't dissolve in each other okay and so you're going to as things cool down they're going to separate into two layers you're going to have your organic layer and then your aquous layer now which one should be on top organic layer should be on top right so the organic layer will be on top the aquous layer will be on the bottom the acid layer will be on the bottom um and what you're using for a receiving flas for your simple distillation is a graduated cylinder so that you can actually measure the size of the two layers okay and the reason you're doing that um and there's a video posted on chem the chem 255 d-11 Moodle site so make sure you watch the video for how to set things up um you're watching those two layers and you're going to measure the size of those two layers um the boiling point range of the mixture is then lower than either individual boiling point okay so like when you're watching the distillation if you collect the boiling point range it's not necessarily going to make sense for Nar sulfuric acid or for the alkenes because it's a mixture that is being distilled over okay so just keep that in mind but the distillation is ended when all the alkenes have distilled over so that is where you are looking for the size of the individual layers okay you're waiting until the or organic layer stop stops growing in size stops increasing in volume once it's stopped increasing in volume and you've distilled enough of the aquous that you can see the difference in the two layers um so that you can separate them in your separatory funnel then you are done with the distillation so you're not distilling all of the mixture over you're only distilling enough to collect all of your alkenes plus probably a couple milliliters of aquous solution so you can see the difference in the two layers okay um and organic layer is going to be the top layer in the graduating graduated cylinder okay um the boiling point will be close to 100° but again it's not going to match either nine molar sulfuric acid or or the alkenes now once you're done with the distillation be super duper careful with that organic layer that is all of your product for experiment 11 and it's only going to be about 3 to 5 milliliters okay and at no point in experiment 11 are we going to mix it with a solvent we're going to be working with it as a neat liquid throughout the workup okay so you've got to be really careful once you're done with that distillation put your graduated cylinder in a safe spot make sure it's not going to tip over also it's really tempting to take all the plastic pieces off and then try and balance the graduated cylinder without plastic pieces on it don't do that because that's a great way to knock everything over and then lose the contents of your graduated cylinder and then you've lost lost your alen okay um so for the workup first of all we're going to let everything cool down to room temperature we've got all this glassware now coated with acid we've distilled over an acid mixture with our alken so let everything just cool down to room temperature once you've taken the heat off okay then we slowly will take things apart okay and your graduated cylinder or the contents of your graduated cylinder are eventually going to go into your separatory funnel so you can separate those two layers separate the aquous layer and separate the organic layer which is your alken layer um and you're just going to do that by draining the lower aquous layer um again small organic layer so be really careful we're not adding any solvent to it we don't want to add any solvent to it so make sure you're super careful with that alken layer now we're going to wash the organic layer with 5% sodium bicarbonate solution so remember from last week what wash means is we've got our organic layer already in our separatory funnel okay we're going to add our um 10 milliliters of sodium bicarbonate solution okay then you're going to shake and vent shake and vent that mixture three times then you're going to separate the um aquous layer off the bottom okay so all of that is involved in the word wash all right um so add 10 MERS um of bicarb to the organic layer shake and vent three times we want to be careful of the bicarbonate we're going to get some pressure buildup of that acid and base reacting together and then we let our layers settle so that we can drain that lower aquous layer okay then we're going to dry our organic layer with magnesium sulfate um so to do this put your organic layer in your very smallest lamire flask which is your 255ml lamire flask okay and then you're going to add just a little bit of a at a time of magnesium sulfate till you have some clumping with a little bit free floating you have such a small volume of alken if you dump in a bunch of magnesium sulfate from the get-go you're going to make kind of like pancake batter and it's going to be really hard to filter out that magnesium sulfate okay so add a little bit swirl it around see if you have enough in there if you need a little bit more then add a little bit more and then let it sit with Saran wrap on it with plastic wrap on it for about 10 minutes okay but be really careful not to add too much remember if we have enough when we swirl it we get what looks like a snow globe okay and remember with make sulfate we never weigh it you're just adding what you need to dry your alken you're not going to weigh it okay um but do be careful um we swept up a lot of magnesium sulfate last week so do be careful when you're adding it to youri flas to add it carefully and if any spills you you sweep it up um so then after we've let it sit for 10 minutes then we're going to use what's called a filtering pipet um and so what the what's going to happen is there's a video posted on Moodle to show you how to do this but you're basically going to take a clean pipet so not one from your drawer but a completely clean pipet and you are going to take a little bit of a chem wipe and we've got um little sticks that we've put together for you where you're going to put that into the pipet and that basically makes it so it can filter so then you're going to run your alen through that pipet and it will let the alken through but it'll hang on to the magnesium sulfate so you don't get any of that in your in your final product because again we're going to use GC we can't have any solids in our final product for GC analysis okay when you are done with your filtering pipet make sure you rinse it so done meaning you've got all your alken out and you're done using it um you're going to rinse it with acetone so P you're going to squirt a little acetone through the pipet into the organic waist mainly just because those stink a lot and we want to try and get the alen out of it before we put it in the glass waste okay so run some acetone through it and then in the reagent hood is a beaker to put the used filtering pipets in so that's where your filtering pipet goes don't put it in the glass waste right away we want to make sure they don't stink before we put them in the glass waste okay we need to collect just like experiment 8 we need to collect the mass of our product so when you are using your filtering pip pad and filtering um your alken um not really solution but your pure alkenes through um the filtering pip pad it's a good idea to already know the mass of the vial you are filtering into because then it is really easy to collect the mass afterwards of your alkenes so get the tear weight of the vial and then the cap that you're going to use to cap it before you start filtering the alkenes and then filter into it and then you can easily collect the mass um after you're done filtering it okay you're going to prepare a GC sample so again make sure that the alken mixture is dry okay so we use magnesium sulfate to make sure it's dry there should be no visible water and make sure you can't see any solids if after that filtration you see any solids then you need to filter it again okay so um if you filter it once and you still see solids in what you've filtered we'll have to send it through the PIP another pipat filter again to make sure it's completely solid free okay then we'll add one drop to a GC vial fill the neck with pentane and turn it into the sample block then fill out the sample sign in sheet the um GC vials and the pentane are in the Ada hoods um and then on the sample blocks you have your drawer numbers the first slot right next to your drawer number just to the right is where sample eight for experiment 8 goes the second slot is where experiment 11 goes okay so make sure you put them in the right spot and then on the sign-in sheet there's a place for your name place for experiment 8's um sample ID and a place for experiment 11 sample ID they should be two separate IDs because you're supposed to have experimental note or notebook Pages for the experimental for eight separate from experiment 11 so make sure you're keeping everything separate in your notebook okay and then again the GC data will be returned to you by your lab Professor once once it is ready once you've collected the mask and prepared your GC sample then collect the IR spectrum and for um experiment 11 you're going to compare um the IR spectrum to a literature IR spectrum for an alken so if you made three octe you could compare it to um trans three otine or if you found Cy three octe something very similar to the alen that you made mainly um think about like what the predominant alen should be and look for that first if you can't find that then use one of the less predominant products but you want to want it to be as close to what you were supposed to make as possible for the comparison okay and then again you're going to put together a table like page 520 of your lab manual um so the report for experiment 8 and11 like I mentioned um for the Tuesday Labs it's due on November 19th for the Thursday Labs it's due on November 21st so that's two weeks from now remember from last week we talked about the same page also your experiment 11 prelab make sure you put that on a clean um the next clean notebook page after what you've written last week for experiment 8 okay so you've got to be careful with the bookkeeping in your lab notebook of keeping things on separate pages all right um and then the conclusion that you write will be combined for both experiments 8 8 and 11 and in lab we'll give you some instructions for that so that's basically experiment 11 but what we need to talk about is how you are analyzing experiment 11 which is through gas chromatography so a couple weeks ago we talked about gel permeation chromatography this week we're talking about gas chromatography what did I say about the word chromatography what does that always mean separation okay so we're using um gas chromatography which is a separation technique um using an inert gas SO gas chromatography um primarily separates compounds based on boiling points and vapor pressure and potentially the polarity of molecules depending on what type of gas chromatography column you are using so keep in mind boiling point ranges is primarily how things are going to be separated for your sample there is a mobile phase and a St stationary phase so remember we talked about with chomatography there's always a mobile phase and a stationary phase the stationary phase for GC column is there is a stationary liquid phase right on um the inner part of the column where the gas passes through okay so it's this liquid stationary phase um that the gas will pass through and that that is the stationary phase so that does help with the separation and if we were to separate things based on the polarity of molecules that would um have some some type of um characteristics as far as polarity it' um most likely be a more polar type of stationary phase the one we're using is relatively non-polar okay the mobile phase is the carrier gas that helps carry the sample through um the gas chromotography column and so it's this um gas that helps helps run push the sample through in our case that is helium gas our carrier gas is helium gas and you usually want something that's a nert that's not going to react with your sample okay whoops hang on um now what happens is the sample is heated in the in the GC injector and forms a vapor before it enters the column so then it goes into the column as a vapor then it's cooled to the initial temperature of the GC column so this is kind of SCH schematic of a a gas chromatograph um ours has a big Auto sampler on top of it that's how we run all the samples but the sample is injected into the injector right before it goes onto the column and it's vaporized here in the injector then runs through um then as it enters the column it then cools to the temperature of the column which is cooler than the injector and then as that temperature of the column is increased it will run through the column and separate out based on boiling point and then eventually come out the detector um so in the column we've got this Vapor that comes up and meets up with the column that column is cooler than the injector so it cools down and anything that is less volatile is going to hang out on that column longer than the more volatile components so things that are more volatile as that column is heated up they will um become more of a gas that'll be swept with the carrier gas versus the less volatile components it will take more heat and take more time on that column before it is swept with with the carrier gas so bottom line when you're looking at gas chromatography things that are um have a higher vapor pressure and more volatile will come off the column sooner so things with a lower boiling point will come off sooner things with a higher boiling point will come off later that's kind of your order of ution with gas chromatography okay so here's an example of different different types of columns um and and what that um stationary phase is depending on what what type of column that you want okay um all of these phases are high molecular weight polymers that are liquid at room temperature and they're not volatile enough and they're not going to break down they're thermally stable so on the column they won't volatilize themselves and they won't thermally break down as as that column is heated on the gas chromatograph so then as the sample comes off the GC column it's in our case it's detected now there's multiple different types of detectors but in our case it's detected with a flame ionization detector and the flame ion ization detector it's also known as an FID is a very sensitive detector and it's good for the analysis of mixtures of oxidizable organic compounds okay now what happens is when a component that's come off the column reaches the flame so here is where that sample Inlet is that sample coming off the column and then we also have a a hydrogen Inlet and then an air Inlet um when that sample comes off the column and enters the detector um when it reaches the flame it becomes ionizes ionized and it loses an electron okay and so now it's a charge species and it produces current proportional to the amount of sample that's being burned so as that sample comes off it's ionized and here is the ion collector it's it's producing a charge proportional to that sample size so that's how it's Det detected and then how its sample size can be Quantified so you know how much of it is in the sample okay um the carrier gas is inert so as it goes into the detector it is not changed by the flame okay and it is not ionized um so for experiment 8 and 11 the column that we use is relative ly non non-polar so that means again that the separation is primarily going to be based on the boiling point ranges of the compounds with lowest boiling compounds again coming off the GC sooner later boiling compound or higher boiling compounds coming off later and what is measured in coming off the GC is the retention time how long it takes to come off the column so what you're seeing is a measurement in minutes of how how the Peaks come off you're looking at an actual time of how those Peaks come off um again the carrier gas um or the mobile phase is inert its helium and we can calculate the flow rate taking the column length divided by the retention time for for me methane so they look at methane as far as gas chromatography to give um consistent results for figuring out what this flow rate is you're not going to have to calculate that just know that the flow rate is usually somewhere 30 to 40 um cmers per second so the data you're going to get is going to be basically like I've put two pieces of of paper together here so you're going to have one piece of paper that is just this a print out of your data and another piece of paper that's your chromatogram okay so on that piece of paper that has your data you'll see Peak numbers and then you see RT retention time in minutes so this is the retention time in minutes of the different Peaks and then over here it tells you the percentage of the total mixture that each Peak um represents okay once your your GC data is collected um a a list of standard retention times is going to be put together and so then you will use that list of standard retention times to figure out where your different components are so there's going to be information on there about the different alcohols and what their retention times are so you can identify your alcohol so you'll have a comparison um retention time and then you'll look at your data and then you'll have different alkenes that you can look at okay so you're going to put together a table like this like I said in those standard retention times both the three and four heptanol are going to be listed and the three and four octanol are going to be listed and then we give you information for um the hepes and the octanes so for the heptin in that table you're going to see the relationship between the CIS and trans heptin so you can figure out how the CIS and trans compounds are related for the octanes we show you how they're related by positional isomer so we show you the um octanes as transfor octanes trans three octane um trans 2 octane okay you're going to use the information of the and the heptin to kind of put things together okay so the relationship you see of CIS and trans hepes that also is a similar relationship for the octanes what you see with the octanes about the positional isomers you have a similar relationship with the hepes okay so use use all that information for figuring out where your Peaks are in your in your GC data this table is in experiment um 10 and you're going to put together a similar table where you list your standard retention time and that'll come from the table that you are going to be given then the retention time from your actual data okay then the area from your GC data and the percent area so let me show you here this is the peak area and then again the percentage okay so whoop wrong way so area and percent area Okay and then you're going to list the identity based on the standards now for some of your um Peaks you won't have a standard retention time for everything so you have to use the relationships of how sis and trans are related to each other and how the different positional isomers are related to each other to figure out where your uh what the identity of some of your Peaks are keep in mind though for every trans alken there will be a Cy alken okay so you won't see just a bunch of trans alken and no CIS isomers for every trans isomer there will be a CIS isomer so keep that in mind as well okay um so this table is on page 1011 of the lab manual another note is you want to eliminate any peaks with a retention time of of 2 minutes or less and and then recalculate and actually this is probably about 2.2 minutes or less and then recalculate the area by subtracting from the total area Okay um that will happen very infrequently but if you do have any Peaks then you want you want to subtract those okay um now you should put together a table like this for um for your lab notebook but also in your experiment 8 and experiment 11 report you should have a GC table for experiment 8 and then you should have a GC table for experiment 11 so in your report you should have a table for your IR data for each each experiment as well as a table for the GC data for each experiment okay and then don't forget to collect Mass um for for each of those compounds as well all right questions you guys have all right that is all I have for you guys today