OCR 2017 A Level Chemistry A Topic Exploration

© OCR 2017

A Level Chemistry A Topic Exploration Pack – Organic Synthesis Identifying functional groups © OCR 2017

• At A Level there are many functional groups to recognise and memorise. One way to deal with this large amount of information is to break it into chunks. • On the following slides, the functional groups have been grouped with other similar groups. • The names of the groups (like ‘simple functional groups’) are not official titles. They are just a reference for this activity, and you don’t need to learn them. © OCR 2017

Simple functional groups Type of compound Functional group Alkene C=C Amine –NH 2 Alcohol –OH Nitro compound –NO 2 Haloalkane –Cl; –Br; –I Nitrile –CN Alkenes include a double bond. The other groups are attached to the carbon chain or a benzene ring. © OCR 2017

Simple carbonyls Type of compound Functional group Aldehyde Ketone These have an oxygen atom double bonded to a carbon, which itself is bonded to only carbon and/or hydrogen. © OCR 2017

Compound carbonyls Type of compound Functional group Carboxylic acid Acyl chloride Cl 1° amide These have an oxygen atom double bonded to a carbon, which is bonded to another atom other than carbon or oxygen. © OCR 2017

Bridging groups Type of compound Functional group Ester 2° amide (peptide) Acid anhydride Here, a carbon is double bonded to an oxygen and bonded to another atom other than carbon or hydrogen. This atom in turn is bonded to another carbon chain. © OCR 2017

Organic salts Functional group Diagram Carboxylate salt Phenoxide salt These have a metal ion bonded to an oxygen ion. The metal is most commonly sodium. © OCR 2017

Aromatics / arenes These contain a benzene ring, often with alkyl groups or other functional groups attached. © OCR 2017

Phenols © OCR 2017 These contain a benzene ring with a –OH group directly attached, often with other alkyl groups or functional groups attached.

Identifying the groups • When given a complex unknown molecule it is important to be able to rule out certain groups to make identifying it easier. • The following flow chart should help you to reduce the number of options down quickly. • The blue boxes are key questions to help you rule certain options in or out. © OCR 2017

Is there a benzene ring? Yes Is there a –OH directly attached? Yes Phenols No No Does the main chain contain anything but carbon? Aromatics Yes Bridging groups No Does it have a C=O bond No © OCR 2017 Simple functional groups Yes Does the carbon have any other groups attached? No Simple carbonyls Yes Compound carbonyls

Tasks • The worksheet contains pictures of molecules. For each molecule you need to identify all of the functional groups. • For an extra challenge, have a go at naming the basic compounds. • The advanced molecules are intended to have some discussion points for the group. © OCR 2017

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