why are these not counted as methyl groups?

Straighthate

2

the CH3 groups on the diagram are not counted as methyl groups, how come?

Reply 1

Infraspecies

16

I count them as methyl groups, and that's all that should matter.

Reply 2

langlitz

17

Original post by Straighthate

the CH3 groups on the diagram are not counted as methyl groups, how come?

They are methyl groups. /thread

Reply 3

Straighthate

OP

2

Original post by langlitz

They are methyl groups. /thread

in the mark scheme for a paper they are not

Reply 4

Infraspecies

16

Original post by Straighthate

in the mark scheme for a paper they are not

Well, they are. So, either the mark scheme was wrong, or the question was worded such to preclude writing "Me" in place of "CH3", or they just decided to put the equivalent "CH3" as the answer.
If it doesn't say "Do NOT accept "Me" or an unlabelled terminal skeletal arm in place of a terminal "CH3" label" then I wouldn't be worried; it all means the same thing.

Reply 5

Kallisto

Entertainment Forum Helper

22

Original post by Straighthate

in the mark scheme for a paper they are not

And is this reasoned by your paper? as the people said it above, they are methyl groups. I can't see another ones.

Reply 6

Ritterschaft

1

Look at the mark scheme again

Reply 7

Kallisto

Entertainment Forum Helper

22

Original post by Infraspecies

Well, they are. So, either the mark scheme was wrong, or the question was worded such to preclude writing "Me" in place of "CH3", or they just decided to put the equivalent "CH3" as the answer.
If it doesn't say "Do NOT accept "Me" or an unlabelled terminal skeletal arm in place of a terminal "CH3" label" then I wouldn't be worried; it all means the same thing.

But why functional groups like methyl groups should be precluded or regarded as equivalent, if they exist?

Reply 8

Infraspecies

16

Original post by Kallisto

But why functional groups like methyl groups should be precluded or regarded as equivalent, if they exist?

I don't know what you're trying to say, reword that please.

Reply 9

username913907

10

They are methyl groups - if the markscheme says otherwise... then its wrong

Reply 10

Kallisto

Entertainment Forum Helper

22

Original post by Infraspecies

I don't know what you're trying to say, reword that please.

Then I have not understand your statement before. I was confused to be honest. What did you mean when you say 'to put the equivalent "CH3" as the answer'? that CH3 should not regarded as a functional group by a paper? I don't get it.

Reply 11

Straighthate

OP

2

Original post by Kallisto

And is this reasoned by your paper? as the people said it above, they are methyl groups. I can't see another ones.

http://www.ocr.org.uk/Images/135165-mark-scheme-unit-f324-rings-polymers-and-analysis-june.pdf

question 3ci, it asks you what functional groups are present in this molecule, as shown by the mark scheme you LOSE mark if you mention that there is a methyl group

Reply 12

brother aldi

2

Original post by Straighthate

http://www.ocr.org.uk/Images/135165-mark-scheme-unit-f324-rings-polymers-and-analysis-june.pdf

question 3ci, it asks you what functional groups are present in this molecule, as shown by the mark scheme you LOSE mark if you mention that there is a methyl group

Methyl groups arent fuctional groups

Functional groups are responsible for the reactions of a compound. Eg alkene

Posted from TSR Mobile

Reply 13

Straighthate

OP

2

Original post by brother aldi

Methyl groups arent fuctional groups

Functional groups are responsible for the reactions of a compound. Eg alkene

Posted from TSR Mobile

****

Reply 14

EdmundWoodstock

2

Original post by Straighthate

http://www.ocr.org.uk/Images/135165-mark-scheme-unit-f324-rings-polymers-and-analysis-june.pdf

question 3ci, it asks you what functional groups are present in this molecule, as shown by the mark scheme you LOSE mark if you mention that there is a methyl group

See, you took the question out of context. When a question asks you to name the functional groups, you're not supposed to name every single group of atoms in the molecule, only the "special" or specific ones that give the molecule its particular properties and/or reactivity.

So for this molecule I'd say the functional groups are the lactone and the alcohol.

(edited 8 years ago)

Reply 15

Kallisto

Entertainment Forum Helper

22

Original post by Straighthate

http://www.ocr.org.uk/Images/135165-mark-scheme-unit-f324-rings-polymers-and-analysis-june.pdf

question 3ci, it asks you what functional groups are present in this molecule, as shown by the mark scheme you LOSE mark if you mention that there is a methyl group

Yeah, but I don't get it why this should be wrong. The whole molecule has three CH3-group and one OH-group. And I can't see a plausible reasoning.

But perhaps these groups are regarded just as parts of the molecule? no, that is senseless.

EDIT: okay, I have read the posted statements above. So I see the sense.

(edited 8 years ago)

Reply 16

EdmundWoodstock

2

Original post by Straighthate

http://www.ocr.org.uk/Images/135165-mark-scheme-unit-f324-rings-polymers-and-analysis-june.pdf

question 3ci, it asks you what functional groups are present in this molecule, as shown by the mark scheme you LOSE mark if you mention that there is a methyl group

I also think it's slightly oversimplified to call the C=O next to the O just an ester, when it's actually a lactone (cyclic ester). A lactone is more reactive than a normal ester because in a normal ester there is additional stabilisation in the Z conformation provided by the overlap of the oxygen lone pair and the C-O sigma anti bonding orbital of the C=O bond.

(edited 8 years ago)

Reply 17

Kallisto

Entertainment Forum Helper

22

Original post by brother aldi

Methyl groups arent fuctional groups

Functional groups are responsible for the reactions of a compound. Eg alkene

Just to hedge my bet: functional groups in the narrower sense are the ones who are reacting with each other and forming a bound between molecules? so the NH2- and COOH-group of amino acids in charged states for instance?

Reply 18

Straighthate

OP

2

Original post by EdmundWoodstock

I also think it's slightly oversimplified to call the C=O next to the O just an ester, when it's actually a lactone (cyclic ester). A lactone is more reactive than a normal ester because in a normal ester there is additional stabilisation in the Z conformation provided by the overlap of the oxygen lone pair and the C-O sigma anti bonding orbital of the C=O bond.