HSC Chemistry — Module 7
Functional Groups — Flashcards & Quiz
Functional groups are the reactive sites that define organic chemistry, and recognising them is essential for HSC Chemistry Module 7. You need to identify alcohols, aldehydes, ketones, carboxylic acids, esters, amines and amides from structural formulas, and predict how each affects physical properties such as boiling point and solubility. IUPAC naming follows directly from group identification — practise reading a structure, finding the highest-priority group, and assigning the suffix. Group recognition is a free-mark builder when you are confident.
Key Points
- Functional groups are the reactive sites of organic molecules — they determine physical properties and chemical reactions.
- Hierarchy (IUPAC priority high to low): carboxylic acid (-COOH) > ester (-COOR) > amide (-CONH₂) > aldehyde (-CHO) > ketone (-CO-) > alcohol (-OH) > amine (-NH₂).
- Alcohols oxidise in steps: 1° → aldehyde → carboxylic acid; 2° → ketone (stops there); 3° → resists oxidation.
- Carboxylic acids + alcohols → esters (sweet-smelling, fragrances/flavours), catalysed by H₂SO₄; reverse = hydrolysis.
- Amines are basic (lone pair on N accepts H⁺); carboxylic acids are acidic; amides link the two in peptide bonds.
- HSC skill: identify ALL functional groups in a structure, then predict solubility, boiling point trends, and expected reactions.
Common Mistakes to Avoid
- Confusing aldehydes (C=O at end of chain) with ketones (C=O in middle of chain).
- Mistaking carboxylic acids (-COOH) for esters (-COO-) — esters lack the OH.
- Forgetting amines are basic (they accept H⁺) and carboxylic acids are acidic.
- Assigning wrong IUPAC priority — carboxylic acid > ester > amide > aldehyde > ketone > alcohol > amine.
- Not recognising that alcohols oxidise differently based on class: 1° → aldehyde → carboxylic acid, 2° → ketone, 3° → resists.
Exam Strategy
HSC Module 7 functional group questions ask you to (1) identify groups in a structure, (2) predict reactions, or (3) assign IUPAC names. Always identify ALL groups first, then choose the highest priority as the principal group for naming. For reactions, link the group type to its characteristic reaction (alcohol oxidation, carboxylic acid + alcohol → ester).
Sample Flashcards
Q1: Name the main functional groups studied in HSC Chemistry.
Hydroxyl (-OH): alcohols. Carboxyl (-COOH): carboxylic acids. Ester (-COO-): esters. Amine (-NH₂): amines. Amide (-CONH₂): amides. Carbonyl (C=O): aldehydes (-CHO at end) and ketones (C=O in middle). Halogen (-X): haloalkanes.
Q2: What is the difference between an aldehyde and a ketone?
Both contain the carbonyl group (C=O). Aldehydes have the C=O at the END of the carbon chain (bonded to at least one H). Ketones have the C=O in the MIDDLE (bonded to two carbon groups). Aldehydes can be oxidised to carboxylic acids; ketones cannot.
Sample Quiz Questions
Q1: The -COOH group is called a hydroxyl group.
Answer: FALSE
The -COOH group is a CARBOXYL group (found in carboxylic acids). The -OH group alone is the HYDROXYL group (found in alcohols).
Q2: Aldehydes have the carbonyl group at the end of the carbon chain.
Answer: TRUE
Aldehydes have the -CHO group at the end of the chain. Ketones have the C=O group in the middle of the chain.
Revision Tip
Functional groups are recognition-based — build a Revizi flashcard deck with structures on one side and group names on the other, and drill both directions.
Related Concepts
Last updated: March 2026 · 2 flashcards · 2 quiz questions