cis-trans and E-Z naming scheme for alkenes | Alkenes and Alkynes | Organic chemistry | Khan Academy

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Cis-Trans and E-Z Naming Scheme for Alkenes. Created by Sal Khan.
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Organic Chemistry on Khan Academy: Carbon can form covalent bonds with itself and other elements to create a mind-boggling array of structures. In organic chemistry, we will learn about the reactions chemists use to synthesize crazy carbon based structures, as well as the analytical methods to characterize them. We will also think about how those reactions are occurring on a molecular level with reaction mechanisms. Simply put, organic chemistry is like building with molecular Legos. Let's make some beautiful organic molecules!
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[@caesar1752]

If you were to come over to my place asking me to name those stuff first thing i'd say is "wtf!" LOL

[@MonkeyDLuffy-xr4fl]

Ayyy Caesar >:)

[@NFLDRAFT2018]

nah I'm pretty sure that's Gangster Gastino

[@jiren6637]

GoOMMMuuuuu GOMomuuuu NOoooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo

[@Ezrik2006]

@@jiren6637 Zatling Zun!

[@luisrcks]

Z zame zide

[@ollydavis2495]

TogeZer and Epart

[@MsPerva]

Olly Davis Nice 😉😊🌹

[@ollydavis2495]

MsPerva lol after i commented this I got an E in my AS exam so it's questionable how useful that is...😂

[@MsPerva]

Olly Davis But he explained it very clear ☺

[@ollydavis2495]

MsPerva yeah but me and chemistry, we don't bond

[@realityweasel8461]

If you came over to my house and asked me to name this molecule, I'd kick you out.

[@navjotsingh2251]

Lol what if someone stops you in the street with a gun to your head, and your only way out is to name the molecule!?

[@skin_jeggings9420]

Navjot Singh I would get shot

[@baby00040007]

the sound of ur voice comforts me that i will do well in chem

[@itssciencebitch548]

It is zusammen not zussamen and you made my day with your pronounciation. Thank You. You are awesome by the way

[@Stagprince1000]

he pronouced that ok-ish its the entgegen part which took me a bit of time to figure out. he pronouses it engigin but its pronouced more like ENT-GEA-GAN

[@alskdj19]

you are absolutely helping me not fail. or not as bad as i would have. amazing how easy things are if things are explained well.

[@UneasyTortoise]

i prefer 2-butene

[@TheOldirishfan3130]

+Dovahkrab When I was learning this, the fact that profs never named molecules the same way frustrated me.

[@juliakhamis6214]

Hero...exactly, makes things simpler.

[@MonkeyDLuffy-xr4fl]

Not the best if the molecule is complex

[@nourish0]

I'd love having Sal at home asking me questions like these.

[@mostwanted092]

"If i were to come over to your place..." O_O love the introduction

[@afzalk543]

I dunno what would I do without Khan Academy. Thank you so much...

[@dstein3597]

Watching this 1 hour before my University exam and Khan you saved my ass! Keep up the good work!

[@hanajb8317]

if i pass my course this year , you'll be one of the strong reasons , so think you

[@sorayarother7548]

Great video but the German pronunciation went so wrong 😂

[@rahulbhardwaj2948]

Wii be my friend

[@nadjalovekari]

Lol first I was like what's this word until he said it's German I understood it 😂😂

[@jakedeering4761]

It seems that 'cis' and 'trans'so only apply when you have one functional group between the carbons you are compairng because the terms are for comparing hydrogen placement. You'll notice in the video that when a molecule is 'cis' or 'trans' the hydrogens are also 'cis' or 'trans' relative to each other. Therefore you cannot call a molecule with two functional groups on it 'cis' or 'trans' because there are no hydrogens to compare--only functional groups. So while the E-Z system is more widely applicable, both systems are equally correct to use regardless of age.

[@erikbok6059]

LMAO, that German is terrible :P

[@flok3rous]

Zusammen, not zussamen. Great video!

[@kainatbhatti689]

Best way to find every topic relate to ur sub Chem. Good

[@cursed4living]

I believe the E and Z naming convention is only used when there 3 or 4 substituents on the two double doubled carbons. If there are only one or two, then you would name the molecule cis or trans.

[@bjamespijisilod]

Does But-2-ene is the same as 2-Butene since our chemistry teacher recognize it?

[@cs_in_10_minutes]

James Piji Bulactiar Ya

[@jorgebaquerizovalladolid3247]

@ᴀʟ☹ stop were struggling enough as it is

[@itachicrasian2]

great video. i know this isn't related to the video, but i love going to these more scholarly videos and not seeing immature tolls comments everywhere.

[@schmid777]

i like the way you pronounce "entgegen" :D it´s completely wrong but it sounds so cute xD and thanks for the video

[@Jojo-kl6tx]

Awesome video! Just wanted to point out, there's a slight difference between cis/trans and (Z)/(E) : when you have two DIFFERENT funcional groups on one side, it's not cis anymore, but still (Z). I was kind of confused by this at first. But I guess you talk about this more in the other video you mentioned. Also, love all the germans commenting about “how bad your german is“. I just thought your pronounciation was cute.😁 We're not here for freaking german lessons anyways.

[@Isis-wm4po]

I think this is my favorite video. I've watched it several times, and I think it's because of the opening. "If I were to come over to your place and said, "name this molecule." My place? For some casual conversation about nomenclature? Well, sure!

[@JackMW1992]

the way i remember this is samzies... like the way a thirteen year old girl would say the word same. works for me

[@Furyflow]

Haha this video is awesome! As a german it's incredibly funny how you pronounce this words. I thank for you the video, just to correct you with the words it's: Entgeeeeegen (the pronounciation) and it's written "zusammen" the rest is absolutely fine thank you

[@kamabokogonpachiro6797]

uploaded 12 years ago but still is useful

[@biochem86]

im not sure if thats technically still E or Z considering E/Z naming is only used when all 4 groups differ, thats just the way i learned so I could be wrong but i know cis/trans would be the names that are prefered

[@Katie-kp6cf]

corrections: -‘entgegen’ actually means ‘opposite’ and is pronounced “ent-gaeg-en” -it’s actually ‘zusammen’ (not zussamen) and is pronounced “tsoo-zamm-en”

[@triplemgaming5103]

This doesn’t clear anything up for non-Germans lol

[@fleshcookie]

Sal really enjoys saying these names.

[@SigmazT]

Thank U sir it help me alot

[@mishkatislam3235]

Please make a video on this in bangla.So that,this can be helpul for me.

[@sevvaltann]

thank you !!

[@Ratman9339]

@R2SweetTooth Rotate around the central bound? Both have double bonds, the pi bond between 2nd and 3rd C do not allow the rotation, so, trans or cis, it will not rotate, in this case.

[@hbs1192]

Can you please tell me how is the most stable z or E and why I need it please

[@heyiammoha220]

Thank you so much

[@namrathsai8867]

Sal is the best

[@OctoAri]

Hence the statement "We will do examples on whether or not to label something E vs trans, or Z vs cis on the next video." He was just doing an introduction on what they mean.

[@ZAsym]

short, precise. Always handy

[@espen180]

"Together" is German is actually written "zusammen", not "zussamen" as you wrote in the video. :) Otherwise very nice video. Looking forward to the next one.

[@Tino81295]

thank you so much, never going to forget that now :)

[@redshuyin06]

Based on my study, E and Z are only applicable for such molecules that are trisubstituted. In this case, it's more comfortable to use the cis-trans naming, provided the two substituents are identical.

[@no-handlleee]

so simple, thanks!

[@curtpiazza1688]

😊Thanx!

[@syreenakurtz7304]

entgegen means "against/contrary to"!! love the effort though.. love these videos even more!!!!

[@g8ming4noobs32]

Zussamen 😂😎 finally something is named in my mother tongue

[@biotch77]

when i see Z i read it in my head like "Zis" since it sounds like cis. theyre not always the same thing but it helps me remember what it is :p

[@fongg2]

thanks, i learned more than i should have!

[@rafaeltavarez4025]

Thank you for the clear explanation

[@Aynsor]

SAYED BROUGHT ME HERE!

[@norwayte]

"entgegen" maybe is better translated as "in opposition to". And right - "together" is written "zusammen" in german.. Keep on going.

[@F.sweet1]

Wow this was so helpful thank you!!!

[@francila09]

Hey sal! Thank you so much fr the video. But what is the difference between conformation and configuration??

[@amal-ti2zz]

conformations are different shapes or orientations of the same molecule- configurations are different arrangements that require the breaking of bonds

[@lifeintechnicolorii4715]

holy crap thank you so much1!!

[@abhivish2017]

Khan academy is best..

[@aras-m]

Thanks a lot for the video, but it's "zusammen" for together

[@alimamstudying9462]

Thank uuuu

[@darinaliga3779]

Perfect

[@Elizren]

E is for entgegen which is German for opposite, z is zusammen which is German for together

[@claramaiwald5064]

Hi I would like to say that you explained it very well, I totally understood everything . But I would like to add that I am German and the german word "entgegen" means "contrary to" or "opposite" . Bye

[@isobel64]

wish you had videos regarding cis and trans position on chair confirmations

[@waytoobiased]

wish you had videos regarding cis and trans position on gender confirmations

[@subhashmodak7890]

Very good explanation

[@vanessanu6751]

haha oh my gosh how cute Sal pronounce the german words .. :D

[@RossM96]

@dirtypritithings Same thing, some people write them in different ways.

[@MsPerva]

You are the best 👏👏🌹

[@SomeRandomYTer]

This guy is boss

[@R9247W]

At first I had trouble remembering them. Then I realized E and opposite both start with vowels. Then Z and same start with consonants.

[@andreaashley84]

Thank you for your videos- they are great! I have a question pertaining to this one though. If both the "CH3" were on the right side of the double bond and the both "H", would this still be a Cis-But-2-ene?

[@SuperSaiyaman3]

if they were on the same side, it would actually be 2-methylprop-1-ene or 2-methyl-1-propene

[@triplemgaming5103]

@@SuperSaiyaman3 wouldn’t it be 1-methylprop-2-ene?

[@triplemgaming5103]

@@SuperSaiyaman3in other words would you start the carbon main chain from the side with the double bond or the side with the methyl group?

[@KrasBadan]

We were taught that it's called butene-2, but but-2-ene is really funny to say so I'm gonna use it in English.

[@emsci]

The former method is wrong, but-2-ene is the new IUPAC name 2-butene is pre-revision IUPAC name.

[@SomeRandomYTer]

1:06 "Hey Sal that's also but-2-ene!" :-)

[@dedly13]

@Badushaz sal can! cgp books are good too

[@201Nada]

THANKYOUUUUUUUUUUUU

[@ruhansundaresan9118]

If you came over to my place and asked me what that molecule was, the first thing I'd say is probably something along the lines of "Who are you and how did you get into my house"

[@Everythingisalreadytaken69]

the correct translation would be "opposite site"

[@gyanesht11]

V nice.

[@TheGodSaw]

suammen so cute

[@salimy3829]

love your German

[@trishasales714]

How do you know if the element attached to a Carbon is a branch? Is it only a branch if it's Carbon? Could you have Halogens, H or NH2 as a branch?

[@toypy]

thank you

[@wh1plashhhhhh]

So it's different from 2-butene? Or are they the same?

[@ichaangl5154]

How to give name if the other one of double bond is ethanol?

[@domsalute7300]

[@emranmalik_007]

Are they structural isomers ?

[@seemaqueen8034]

Wow 💝💝💝

[@sumanmultani5336]

i like this. niceeeeeee

[@majdigharra4354]

The way you pronounced ''Zusammen'', it should be written like this ''Susamen''

[@rahmanahmed5218]

great explanation but wht is the use of german weird words

[@PhreakPiano]

"Entgegen" means opposite of smt in this case

[@Pompidompy]

Both correct, however but-2-ene is currently the IUPAC standard.

[@tejasgoyal9590]

having difficulty visualizing tans cyclooctene...plz help with a detalied structure...models are highly appreciated(provide link please)

[@junior1984able]

so the single based hydrongen atached to the main chain is ignored

[@trishasales714]

Do you just have to mention cis and trans when you have an alkene?

[@Randybobandy024]

entgegen means opposite ^^

[@Khan-sk2eq]

I have one question If we have one chlorine atom instead of hydrogen atom in the same compound ,then how we assign priority?

[@parv_k]

dichloro dimethyl ethene

[@jmarr123]

I thought he meant, easy Naming schemes.. but he actually meant E and Z.

[@jacksoncollier376]

If you came over to my place and led with that question I'd shut the door in your face

[@CitizenofDystopia]

This video is wrong. Cis and Trans is when you're dealing with hydrogen. E and Z is when you're dealing with priority groups that are trisubstituted.

[@callancoventry3843]

Repeat after me... entGAYgen. No joke.

[@Stefanos-Pikros]

Latin for across :)

[@calledmoe]

you spelled "zusammen" wrongly XD Nice video bruh!

[@calledmoe]

if i did it would have been funny

[@calledmoe]

hahaha xD youre right, my mistake

[@xXFBI3DOo]

gotta zayn