Formulas, functional groups and the naming of organic compounds
Cambridge A-Level Chemistry (9701) · Unit 13: An introduction to AS Level organic chemistry · 9 flashcards
Formulas, functional groups and the naming of organic compounds is topic 13.1 in the Cambridge A-Level Chemistry (9701) syllabus , positioned in Unit 13 — An introduction to AS Level organic chemistry , alongside Characteristic organic reactions. In one line: A hydrocarbon is a compound solely composed of carbon and hydrogen atoms. Alkanes are examples of simple hydrocarbons.
Marked as A2 Level: examined at A Level in Paper 4 (A Level Structured Questions) and Paper 5 (Planning, Analysis and Evaluation). It is not tested on the AS-only papers (Papers 1, 2 and 3).
The deck below contains 9 flashcards — 4 definitions and 5 key concepts — covering the precise wording mark schemes reward. Use the 4 definition cards to lock down command-word answers (define, state), then move on to the concept and calculation cards to handle explain, describe, calculate and compare questions.
The term 'hydrocarbon'
A hydrocarbon is a compound solely composed of carbon and hydrogen atoms. Alkanes are examples of simple hydrocarbons.
What the Cambridge 9701 syllabus says
Official 2025-2027 spec · A2 LevelThese are the exact learning outcomes Cambridge sets for this topic. The candidate is expected to be able to do each of these on the relevant paper.
- define the term hydrocarbon as a compound made up of C and H atoms only
- understand that alkanes are simple hydrocarbons with no functional group
- understand that the compounds in the table on pages 29 and 30 contain a functional group which dictates their physical and chemical properties
- interpret and use the general, structural, displayed and skeletal formulas of the classes of compound stated in the table on pages 29 and 30
- understand and use systematic nomenclature of simple aliphatic organic molecules with functional groups detailed in the table on pages 29 and 30, up to six carbon atoms (six plus six for esters, straight chains only for esters and nitriles)
- deduce the molecular and/or empirical formula of a compound, given its structural, displayed or skeletal formula
Cambridge syllabus keywords to use in your answers
These are the official Cambridge 9701 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.
Tips to avoid common mistakes in Formulas, functional groups and the naming of organic compounds
- › Carefully trace the carbon skeleton after oxidation; a carbon atom becomes chiral if it is bonded to four different groups.
- › The 'horseshoe' in the intermediate must represent the delocalized system and must not include the sp3 carbon being substituted.
- › Define an addition reaction as one where two or more molecules combine to form a single product.
- › In nucleophilic addition, ensure the curly arrow starts from the lone pair on the Carbon atom of the cyanide ion.
- › State that sp2 orbitals overlap head-on to form sigma bonds, while p orbitals overlap sideways to form pi bonds.
Define the term 'hydrocarbon'.
A hydrocarbon is a compound solely composed of carbon and hydrogen atoms. Alkanes are examples of simple hydrocarbons.
What functional group characterizes alcohols?
The hydroxyl group (-OH) characterizes alcohols.
Draw the skeletal formula of 2-methylpentane.
The skeletal formula shows only the bonds between carbon atoms. The structure has a five-carbon chain with a methyl group (CH₃) attached to the second carbon.
Give the general formula for an ester.
The general formula for an ester is R-COO-R', where R and R' are alkyl groups. Esters are formed by the reaction of a carboxylic acid with an alcohol.
Name the organic compound with the structural formula CH₃CH₂CH₂COOH.
The compound is butanoic acid. It contains four carbon atoms and a carboxylic acid functional group at the end of the chain.
What is the displayed formula and why is it useful?
A displayed formula shows all atoms and bonds in a molecule. It's useful for visualizing the complete structure, including the arrangement of atoms and connectivity.
Deduce the molecular formula of a compound with the following skeletal formula: a six-carbon ring with a double bond between carbons 1 and 2.
The compound is cyclohexene. Its molecular formula is C₆H₁₀. The ring structure and double bond reduce the number of hydrogen atoms compared to a saturated alkane.
Describe how the functional group dictates the physical and chemical properties of an organic compound.
The functional group is a specific group of atoms within a molecule that is responsible for the characteristic chemical reactions of that molecule. It affects properties like boiling point, solubility, and reactivity.
Name the compound represented by the structural formula CH₃CH₂CN.
The compound is propanenitrile. It consists of a three-carbon chain with a nitrile (-CN) functional group.
More Chemistry flashcards
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All Chemistry FlashcardsMore topics in Unit 13 — An introduction to AS Level organic chemistry
Formulas, functional groups and the naming of organic compounds sits alongside these A-Level Chemistry decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.
Key terms covered in this Formulas, functional groups and the naming of organic compounds deck
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