AQA A2 Chemistry C26 Compound Containing Carbonyl Group Kerboodle Answers

This page contains the AQA A2 Chemistry C26 Compound Containing Carbonyl Group Questions and kerboodle answers for revision and understanding.This page also contains the link to the notes and video for the revision of this topic.
 
Banner 1

C26.1 Introduction to aldehydes and ketones AQA A2 Compount Containing Carbonyl Groups: Page No.  157

1: a Pentan-3-one b Propanal 2
A ketone must have a C= O group with two carbon-containing groups attached to it, so at least three carbon atoms are required.
The C=O group can only be on carbon 2, otherwise the compound would be an aldehyde. c The C=O group must always be on the end of the chain. 3 A hydrogen bond requires a molecule with a hydrogen atom covalemly bonded to an atom of fluorine, oxygen, or nitrogen. There is no such carbon atom in propanone. 4 The hydrogen atom in a.n -OH group in a water molecule can hydrogen bond with the oxygen atom in the C=O bond of propanone.

26.2 Reactions of the carbonyl group in aldehydes and ketonesAQA A2 Compount Containing Carbonyl Groups: Page No. 160

1 w, cr, Cl • Cl 2 a No b A negatively charged nucleophile will be repelled by the high electron density in the C= C. c 3 4 The cN-ions can at.tack the planar C= O group from above or below. In the case of CHCHO this will produce a compound with a chiral centre (four different groups attached to it). This will be a pair of optical isomers. As attack from above or below is equally likely it will be a 50:50 mixture (racemic). In the case of CH3COCH3′ the product will not have a carbon atom with four groups attached to it. It will not therefore be chiral and will be a single compound.

26.3 Carboxylic acids and esters AQA A2 Compount Containing Carbonyl Groups : Page No. 163

1 3-brornobutanoic acid 2 3 The carboxylic acid must be at the end of a chain and therefore in the 1 position. 4 Ethyl ethanoate; methyl propanoate

26.4 Reactions of carboxylic acids and esters AQA A2 Compount Containing Carbonyl Groups: Page No. 167

  1. They react with carbonates and hydrogencarbonates to give carbon dioxide, metal oxides to give salts, and alkalis to give salts.
2 Methanol and ethanoic add 3 Ethanol and methanoic acid 4 They have the same molecular formula but have a different arrangement of their atoms in space.

26.5 Acylation AQA A2 Compount Containing Carbonyl Groups: Page No. 172

1 The carbon of the C= O group is strongly cO+ because, as well as oxygen, it is also bonded to an electronegative chlorine atom whid1 draws electrons away from it. 2 OH-, because it is negatively charged and contains a lone pair of electrons. 3 Because the nucleophile and the acylating agent join together and then a small molecule is lost. 4 Banner 2

Practice questions: Page No. 173

1 (a) CH3OH + CH3CH2COOH → CH3CH2COOCH3 + H2O (b) Nucleophilic addition–elimination (c) (d) (i) A selection of answers are correct here. These are : faster/ not reversible/ bigger yield /purer product/ no acid catalyst required (ii) Anhydride less easily hydrolysed or reaction less exothermic. 2 (a) Nucleophilic addition (b) (i) Name compound Q. 2-hydroxybutanenitrile (ii) (c) (i) methanol in the presence of a few drops of concentrated sulfuric acid; (ii) (iii) CH3CH=CHCOOH 3 (a) (Nucleophilic) addition – elimination; (b) 4 (a) Propan(e)-1,2,3-triol (b) CH3(CH2)16COONa or C17H35COONa Banner 3

DISCLAIMER

Disclaimer: I have tried by level best to provide the answers and video explanations to the best of my knowledge. All the answers and notes are written by me and if there is any similarity in the content then it is purely coincidental. But this is not an alternative to the textbook. You should cover the specification or the textbook thoroughly. This is the quick revision to help you cover the gist of everything. In case you spot any errors then do let us know and we will rectify it. References: BBC Bitesize AQA GCSE Science Kerboodle textbook Wikipedia Wikimedia Commons Join Our Free Facebook Group : Get A* in GCSE and A LEVEL Science and Maths by Mahima Laroyia: https://www.facebook.com/groups/expertguidance.co.uk/ For Free Tips, advice and Maths and Science Help