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Hydrocarbons and Naming Alkanes: Flashcards

Revise alkanes, alkenes and alkynes, homologous series, the stems meth- to dec-, IUPAC naming, isomers and combustion.

10 cardsIntermediate

10 cards

  1. Question
    What is a hydrocarbon?
    Answer

    A compound containing only carbon and hydrogen.

  2. Question
    General formula of the alkanes?
    Answer

    CₙH₂ₙ₊₂ (only C–C single bonds), e.g. propane C₃H₈.

  3. Question
    General formulas of the alkenes and the alkynes?
    Answer

    Alkenes CₙH₂ₙ (one C=C); alkynes CₙH₂ₙ₋₂ (one C≡C).

  4. Question
    Saturated or unsaturated: what is the difference?
    Answer

    Saturated (alkanes): only single C–C bonds, maximum H. Unsaturated (alkenes, alkynes): at least one C=C or C≡C.

  5. Question
    What is a homologous series?
    Answer

    A family with the same general formula and similar chemistry, each member differing from the next by CH₂.

  6. Question
    Stems for 1 to 10 carbons?
    Answer

    meth, eth, prop, but, pent, hex, hept, oct, non, dec.

  7. Question
    The steps for naming a branched alkane?
    Answer

    Longest chain → number for lowest locants → name branches (methyl, ethyl) with di-/tri- → list alphabetically.

  8. Question
    What are structural isomers?
    Answer

    Compounds with the same molecular formula but different arrangements of atoms, e.g. butane and 2-methylpropane (C₄H₁₀).

  9. Question
    How does branching affect the boiling point of isomers?
    Answer

    More branching → more compact molecules → weaker dispersion forces → lower boiling point (pentane 36 °C, 2,2-dimethylpropane 10 °C).

  10. Question
    Products of complete and of incomplete combustion of a hydrocarbon?
    Answer

    Complete: CO₂ + H₂O. Incomplete (too little O₂): also CO and soot (C).