Year 12s: what will be the first way you research your future options? >>

This discussion is now closed.

Check out other Related discussions

OCR F324-June 2013 Chemistry

Scroll to see replies

Reply 1720

otrivine

Why alcohol have short retention time and why alkane would have long retention time?

Reply 1721

Mus1995

Original post by thers

I lol'd at "I'm really bad" but gets 52/60 which is A*

Hydroxyl refers to alcohols, phenols, carboxylic acids etc anything with an OH group. The markscheme thet year wanted you to be more specific.

4(b) OCR tell you that Benzaldehyde is both oxidized and reduced - its not on the spec. It's an application of knowledge question where they give you all the info required to answer it.

It was around 82 UMS. I need 85 for my A* man that's why I'm annoyed, I can't afford to drop any marks. :frown:

Okay so just look at it in context.

Yeah apparently it's nucelophillic addition with the OH(-).

That can attack C(delta+) which will form COH(H)O(-) where the O takes a proton from water?

How would you get a single alcohol? I see a diol forming.

Or do you just take it as oxidation and make a single alcohol?

Posted from TSR Mobile

Reply 1722

thers

Original post by otrivine

Why alcohol have short retention time and why alkane would have long retention time?

Would have thought its something to do with hydrogen bonds forming between alcohols so are more soluble. Alkanes cannot form hydrogen bonds with each other.

Reply 1723

otrivine

Original post by thers

Would have thought its something to do with hydrogen bonds forming between alcohols so are more soluble. Alkanes cannot form hydrogen bonds with each other.

I see, and could you help me on the pdf I uploaded please

were my answers correct for your questions?

Reply 1724

thers

Original post by otrivine

I see, and could you help me on the pdf I uploaded please

were my answers correct for your questions?

Scan : Curly arrows and mechanism correct
You can't react two carboxlyic acid groups together. Only an alcohol with a carboxylic acid.

Answers all correct

I've got to go off now. Might be on later

Reply 1725

otrivine

Original post by thers

Scan : Curly arrows and mechanism correct
You can't react two carboxlyic acid groups together. Only an alcohol with a carboxylic acid.

Answers all correct

I've got to go off now. Might be on later

Sure, but they put repeat unit, dont we join them togehter?

Reply 1726

thers

Original post by otrivine

Sure, but they put repeat unit, dont we join them togehter?

Joining them together would result in 2 repeat units. Look at one half and you will see its identical to the other so that's 2 repeat units. The question says one repeat unit

Reply 1727

Mus1995

This explains my question about 4(b) in June 2012. ImageUploadedByStudent Room1371485978.352008.jpg

Posted from TSR Mobile

Reply 1728

Samtaylor47

Quick question:

How do you do hydrolysis reactions? There is the ones of Ester and Peptides if i'm right?

I understand that with H2So4 its basically the reverse reaction of the formation of the ester and then for alkaline its the same but with 0- and Na+... But when you do it with HCl and things like that? It confuses mee... :frown:

Reply 1729

Samtaylor47

Also, is there any others that i should learn?

Reply 1730

D4rth

Original post by thers

You can't react two carboxlyic acid groups together. Only an alcohol with a carboxylic acid.

For an esterfication I know that's what is happened but aren't acid anhydrides made from the reaction of two carboxylic acids?

Posted from TSR Mobile

Reply 1731

Georgiina_Tee

Who has Jan 13 paper or link to someone who has posted I can only find the ms

Posted from TSR Mobile

Reply 1732

D4rth

Original post by Georgiina_Tee

Who has Jan 13 paper or link to someone who has posted I can only find the ms

Posted from TSR Mobile

Its been posted many times, check the past few pages, its in an attachment and a link.

Posted from TSR Mobile

Reply 1733

Gulzar

Original post by Mus1995

End of module 1. And read this. :smile:

www.chemguide.co.uk/organicprops/amines/preparation.html#top

Posted from TSR Mobile

Thank you so much man, I missed that :rolleyes:

Reply 1734

thers

Original post by D4rth

For an esterfication I know that's what is happened but aren't acid anhydrides made from the reaction of two carboxylic acids?

Posted from TSR Mobile

Formation of acid anhydrides is not on the spec.

Reply 1735

Georgiina_Tee

I've been looking for an hour and 21 minutes now, looked for like the first 20 pages and from the back to the last 10 can you link me please maybe its because I'm on my phone :'(

Posted from TSR Mobile