A Level Chemistry Revision "Structural Isomers"

You can find all my A Level Chemistry videos fully indexed at www.freescienc...
In this video, we look at structural isomers. First we explore what is meant by a structural isomer. I then give you three questions where you work out the structural isomers given a molecular formula. Then for AQA students, we look at chain isomers, positional isomers and functional group isomers.
This video is aimed at the UK A Level Chemistry specifications. Students studying International A Level Chemistry will need to check their specification.

[@sirjunior9006]

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[@user-up5ig3pq2q]

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[@ibrahimshahid9726]

Love the video just got full marks thanks to you on my physics paper

[@alimaqsudi8792]

You are the reason im going to pass my exams

[@JuliaNazneen-ve8ig]

Sir I just wanted to ask why dont we use the first or last carbon chain why is it always the middle ones?

[@KaitlynBurtonISaGOD]

You are a blessing thankyou so much for taking time to teach this in a non complicated way

[@a16sor]

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[@lpsowa4012]

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[@Joseph.Clayton.5678]

Thanks, I love your videos shaun.

[@simranjeetsingh6879]

can you please cover halogenoalkanes? your videos are really helpful. Thank you so much!!

[@georgiastanford9496]

Thank you for this video it is really helpful! I was just wondering, for the example of the chain isomers, is methyl propane also a functional isomer of butane as they have a different functional group (or because butane is an alkane does that not matter)?

[@abdullaharshad7097]

This man is the goat

[@birdie7344]

so helpful! thank you

[@crystal_raindrop]

C5H12 (pentane) also has an isomer 2,2 dimethyl propane which wasn't discussed in the video

[@Freesciencelessons]

I discuss dimethylpropane in the video. The numbers are not needed as it can only be 2,2-dimethylpropane. However, it is not wrong to use the numbers, they just are not required.

[@lisafoundjiminsjamsarmlink5798]

Will we lose marks if we call methylbutane 2-methylbutane etc?

[@Freesciencelessons]

No you wouldn't lose marks as it's not wrong. It's just that the 2 isn't really needed since the methyl group can only be on carbon 2 in methylpropane.

[@AnonymousReader-er4eg]

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[@thisath_renuja]

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[@puddleduck1405]

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[@hanabanana9106]

what's the difference between a functional group isomer and a position isomer? Because aren't they both involving the moment of the functional group

[@Freesciencelessons]

Functional group isomers have the same atoms but different functional groups, for example carboxylic acids and esters. Positional isomers simply have the same functional group at different positions on the carbon chain.

[@hanabanana9106]

@@Freesciencelessons ohhhh okie thank you!!

[@fyre1]

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[@muzzy3015]

....this is the work i have to learn for my iGCSE Chemistry😭

[@Random-sd8ef]

Wait forgive me if I sound dumb rn but why can’t the placements for the double bonds be on 3,4 or 5 in Pentene as a structural isomer at 2:54 ? I’m just asking because it’s very specific.

[@Freesciencelessons]

You always count so that the numbers are as low as possible. Pent-3-ene would be pent-2-ene. Pent-4-ene would be pent-1-ene. Pent-5-ene cannot exist as the number indicates the carbon atom at the start of the double bond so there would have to be a carbon-6 and that would be hexene.

[@Random-sd8ef]

@@Freesciencelessons ahh that makes so much more sense. Thank you! 🙏

[@surxj1991]

Will you start uploading A level Physics video?

[@hm-pj2fh]

Hi.
Aren’t 3-methylbut-1-ene and 2-methylbut-1-ene the same thing (3:12). If not why is there not a 3-methylbut-2-ene and only a 2-methylbut-2-ene?

[@Freesciencelessons]

3-methylbut-1-ene and 2-methylbut-1-ene are different because but-1-ene is not a symmetrical molecule. But-2-ene is a symmetrical molecule so 3-methylbut-2-ene and 2-methylbut-2-ene are the same.

[@selfimp313]

Why are there 12 hydrogens in 2-methylbutane but not 13..
Thank you very much

[@Freesciencelessons]

2-methylbutane is a structural isomer of pentane (C5H12). This means that it has to have the same number of carbon atoms and hydrogen atoms as pentane.

[@ellahewitson9686]

I have a question. How come you did have to show placement of the methyl side chain group in 1-chloromethylpropane and 2-chloromethylpropane? The methyl group is on carbon 2, I thought you always had to show where the side groups are?

[@Freesciencelessons]

In methylpropane, the methyl group can only be on carbon 2. That's because propane only has three carbon atoms. If the methyl group was on carbon 1 or 3 then that would simply be butane not methylpropane. You can call methylpropane 2-methylpropane if you want to but you don't need to.

[@bharadwajeddanapudi8507]

Sir, is 2,2-dimethylprop-1-ene not an isomer of pent-1-ene

[@Freesciencelessons]

2,2-dimethylprop-1-ene cannot exist. If carbon 2 has two methyl groups, then carbon 2 has four single bonds, so the molecule cannot also be an alkene.

[@bharadwajeddanapudi8507]

@@Freesciencelessons oh yeah, my bad sir.

[@hasaanjunaid1842]

@4:19 ,,, sorry but isnt this supposed to be 1 chloro 2 methyl propane

[@Freesciencelessons]

Propane only has three carbon atoms. The methyl group has to be on carbon 2 (if it was on carbon 1 or 3, then the molecule would be butane). So the "2" is not necessary. However, it is not wrong, it is just not needed. You would not lose a mark in the exam if you use the "2".

[@r0safrrr]

I have these in my gcses 😭

[@MohammedAhmed-pb9xm]

Hi Sir,
I think you have made a mistake in the a level atom economy video. The answer should be 79.8% not 78.8%.

[@Neil-cb5sr]

Do you know a good way to revise physics?

[@mehak.ahmed1]

what examboard is this?

[@Nightmare-yw3ku]

Edexcel, OCR and AQA

[@dcikid4031]

Hi

[@angelaemeka8303]

Can you please do Hess’s cycle

[@Freesciencelessons]

Hi. I've already covered Hess's Cycles. They're in the A level Chemistry playlist on Enthalpy. They're called Enthalpy Cycles.

[@mynameiscowareesh4968]

going into a level next year and have no idea what ur talking about lol

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