Naming of molecules

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Turdburger

Was I right to put OH over Cl priority in question 2?

As there's a chlorine on both functionalised carbons, the C(OH)(Cl) carbon takes precedent anyway.

I've not read all the answers but I got:
1. 3-methylhexan-2-ol
2. 2,3-dichloro-3-methylbutan-1-ol
3. 2-methylcyclohexan-1-ol

Turdburger

I think you can name this more than one way, there might be some formally correct way, but no chemist would actually really care --

IUPAC would care. Any chemist in a lab would use a trivial or abbreviated name.

Reply 21

EierVonSatan

Turdburger

Was I right to put OH over Cl priority in question 2?

As Kaeroll said the OH and Cl substituted carbon takes priority over the Cl substituted carbon.

Reply 22

LadySmythe

Christ is this mean't to be for AS?

(not the priority thing, I don't think, it was never mentioned on my syllabus)

Reply 23

EierVonSatan

Loz17

Christ is this mean't to be for AS?

(not the priority thing, I don't think, it was never mentioned on my syllabus)

Yeah these look like AS questions - the priority rules have been included on the new specs - confusing many teachers I believe :tongue:

Reply 24

LadySmythe

EierVonSatan

Yeah these look like AS questions - the priority rules have been included on the new specs - confusing many teachers I believe :tongue:

Haha

But theymust have been taught it at uni though?? You can't teach A level unless you have a degree in that subject

Reply 25

EierVonSatan

Loz17

Haha

But theymust have been taught it at uni though?? You can't teach A level unless you have a degree in that subject

True, but for many teachers this was some time ago (though I'm not sure on the rules of who can teach what with each degree).

Reply 26

LadySmythe

EierVonSatan

True, but for many teachers this was some time ago (though I'm not sure on the rules of who can teach what with each degree).

Yea fair point :smile:

I think its you need to study to one level higher than you can teach, and have a PGCE of course (in general)

Reply 27

Kaeroll

I was taught loose priority rules at college - not R/S configurations and the like, but oxidation state based rules (e.g. carboxylic acid takes priority over alcohol).

Reply 28

Turdburger

EierVonSatan

True, but for many teachers this was some time ago (though I'm not sure on the rules of who can teach what with each degree).

Im 99% sure my GCSE chemistry teacher had a physiology degree. And this is in a top school

Reply 29

LadySmythe

Kaeroll

I was taught loose priority rules at college - not R/S configurations and the like, but oxidation state based rules (e.g. carboxylic acid takes priority over alcohol).

There is nothing on my syllabus on it, and the only think left to be taught i about chemistry in the industry, so product production basically

How fun :rolleyes:

Reply 30

EierVonSatan

Turdburger

Im 99% sure my GCSE chemistry teacher had a physiology degree. And this is in a top school

Yeah but that's two levels below qualification - if they have an A-level then it's fine. I'd be more concerned with graduates holding psedo-relevant science degrees like food science :yep:

Reply 31

raspberryice

EierVonSatan

Yeah but that's two levels below qualification - if they have an A-level then it's fine. I'd be more concerned with graduates holding psedo-relevant science degrees like food science :yep:

2 levels?

Reply 32

EierVonSatan

raspberryice

2 levels?

A first degree is two qualification levels higher than GCSE

Degree ---> A-level ----> GCSE

Reply 33

raspberryice

EierVonSatan

A first degree is two qualification levels higher than GCSE

Degree ---> A-level ----> GCSE

oh right i thought u meant the degree was. k,

Reply 34

Shayke

Which takes priority when it comes to something like an OH group and methyl?

Reply 35

EierVonSatan

Shayke

Which takes priority when it comes to something like an OH group and methyl?

EierVonSatan

2-methylcyclohexanol

OH takes priority over CH3

Reply 36

Shayke

EierVonSatan

Would that mean butyl would take priority over OH?

i.e. Do you compare the first letters still, taking the OH group as hydroxyl, starting with an H (compared to taking is as -ol starting with an O)? lol

Might sound silly, just wanna clear it up =]

Reply 37

EierVonSatan

Shayke

You first look at the connecting atom - the one with the highest atomic weight takes priority so O > C and so OH > CH2CH2CH2CH3.

When the first atom is equivalent you move outwards e.g. C(CH3)3 > CH2CH2CH2CH3.

Reply 38

Kaeroll

Shayke

OH takes priority over any alkyl group. Alkyl groups have the lowest priority (other than hydrogen) generally. I'm not sure of the rule for light elements such as boron - they may be out-ranked by hydrocarbons - but that's not an issue at A level.

Within alkyl groups, effectively the heaviest group takes priority.

Reply 39

User69701

Turdburger

Was I right to put OH over Cl priority in question 2?

2,4-dichloro-4-methylpentan-2-ol is what I would have personally called it. It is a dichloro and an alcohol so it is better to start with the dichloro and finish on an ol.