WJEC CH4 June 2015

Well that clears all the confusion guys. Primary Amides undergo base hydrolysis to form a carboxylic acid salt, primary amides also undergo acid hydrolysis to form a carboxylic acid and an ammonium salt. The reason why it stated that amides undergo base hydrolysis in the june 2013 question was because the question was referring to peptide linkages and the amide/peptide bond is a secondary amide. When you hydrolyse a peptide bond you form a carboxylic acid and an amine, it's exactly how two amino acids are seperated using hydrolysis.

Reply 62

manjot97

Goodnight and goodluck everyone :smile:

Reply 63

OP

Thanks "vodka" for clearing that confusion! So wait, are peptide/amide links always secondary amides. Or am I just going off on the wrong track?

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Reply 64

manjot97

How'd you guys find it? I thought it was a pretty standard paper to be honest.

Reply 65

Fortauna

9

Solid. Goodbye university....

Reply 66

EDIT: Actually I'd say it was pretty difficult, I reckon there'll be lower grade boundaries for that - certainly lower than last summer's which was literally 90% for an A*! I wouldn't worry too much if you found it diffuclt!

(edited 8 years ago)

Reply 67

OP

It was not a nice paper at all :/ the hardest one I've done

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Reply 68

OP

Definitely hoping for low boundaries

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Reply 69

Rosheeen

1

Missed out few questions, definitely struggled with timing :frown:

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Reply 70

The compound W alkene questions were rather funny, I can see them throwing some people off. The first part of section B was also difficult IMO, and the for the 1 marker on the last page, what is missing from the first bullet point, what did you guys write?

Reply 71

steffanjones

Lot more application questions than usual, to make it harder I presume, won't be anywhere near as high as last summer for an A I'd have thought

Reply 72

steffanjones

Original post by Rhetorical Hips

The compound W alkene questions were rather funny, I can see them throwing some people off. The first part of section B was also difficult IMO, and the for the 1 marker on the last page, what is missing from the first bullet point, what did you guys write?

Completely agree, start of question 4 was pretty hard! Had no idea what was missing from the first bullet point, I must have stared at it for a good 2 minutes hahah

Reply 73

OP

So many reactions and conditions didn't come up. So gutted spent ages leading them! Any ideas for grade boundaries?

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Reply 74

OP

Original post by steffanjones

Lot more application questions than usual, to make it harder I presume, won't be anywhere near as high as last summer for an A I'd have thought

Yeah 66/80 was an A last year. Don't think it will be that high :/

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Reply 75

Probably mid to high 60s for an A*

Reply 76

Original post by HG_07

Yeah 66/80 was an A last year. Don't think it will be that high :/

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Yeah definitely not that I can see an A* being closer to 66 than an A

Reply 77

Maxmeisterrr