PEC140 SB12 Tutorial Answers

Embed Size (px)

Citation preview

  • 8/12/2019 PEC140 SB12 Tutorial Answers

    1/5

    PEC140 Introduction to Chemistry

    STUDY BLOCK 1 Tutori!" #ns$ers

    1.

    #"coho" n!me Structure C"!ssi%ic!tion

    propan-1-ol

    OH

    or simply

    CH3CH2CH2OH

    Primary (1o)

    2-methylpentan-2-olCH3

    CH2CH2

    C

    CH3

    OH

    CH3

    Tertiary (3o)

    cyclohexanolOH

    OR

    CH

    CH2

    CH2

    CH2

    CH2

    CH2

    OH

    Secondary (2o)

    -ethyl-3-methyloctan-3-ol

    OH

    Tertiary (3o)

    2.

    &!me Tol!ene (methyl"en#ene) Phenol (hydroxy"en#ene)

    Structure

    CH3 OH

    'o"!r m!ss $2 % mol&1 $' % mol&1

    Boi"in( )oint 111oC 12oC

    Tol!ene is a non-polar hydrocar"onand the only possi"ility or intermolec!lar orces is

    dispersion (ind!ced dipole-ind!ced dipole interactions). Phenol is polard!e to the presence

    o the hydroxyl (OH) %ro!p and is a"le to participate in hydro%en "ondin% interactions. *sample o a compo!nd +ill "oil +hen eno!%h ener%y has "een added to o,ercome the

    intermolec!lar interactions allo+in% molec!les to lea,e the "!l li!id and enter the %as

    1

  • 8/12/2019 PEC140 SB12 Tutorial Answers

    2/5

    phase. /ore ener%y is re!ired to o,ercome the intermolec!lar orces or phenol "eca!se

    hydro%en "ondin% is a m!ch stron%er interaction than dispersion orces.

    3. Phenol is expected to "e more sol!"le in +ater than tol!ene . 0ater molec!les are polar and

    can interact +ith other polar molec!les. Phenol has a polar hydroxyl %ro!p that can

    participate in hydro%en "ondin% interactions +ith +ater. The non-polar str!ct!re o tol!enedoes not allo+ or intermolec!lar interaction +ith +ater molec!les and it is less a"le to

    dissol,e in +ater.

    '.

    C

    OH

    O

    1/nO' H

    1/nO' HCH2OH

    C

    H

    O

    C OH

    H

    H3C

    CH3

    1/nO' H

    C

    CH3

    O

    H3C

    C OH

    CH3

    H3C

    CH3

    1/nO' H

    4o reaction

    5. *n e!ation or the acid catalysed reaction "et+een "!tanoic acid and propanol in the

    ormation o an ester.

    CH2CH2CH3

    COH

    O

    3 CH3CH2CH2OH H

    CH2CH2CH3

    CO

    O

    H3CH2CH2C

    The name o the ester that orms ispropyl "!tanoate.

    .

    4

    CH3

    H

    2oamine

    CH3 CH2

    CH2 C

    4H2

    CH3

    CH3

    1oamine

    2-methylpentan-2-amine

    4

    CH3

    CH3

    3oamine

    2

  • 8/12/2019 PEC140 SB12 Tutorial Answers

    3/5

    CH

    CH3CH2CH2

    CH3

    4H2

    1oamine

    pentan-2-amine

    4H2

    1oamine

    cyclopentanamine

    4H2

    1oamine

    2-methylpentan-1-amine

    6.

    &!me *niline (amino"en#ene) Phenol (hydroxy"en#ene)

    Structure

    4H2 OH

    *!ter so"u+i"ity !t 0oC 3. %7188 m9 .3 %7188 m9

    :oth compo!nds ha,e a de%ree o +ater sol!"ility d!e to the presence o polar amine and

    hydroxyl %ro!ps. *mine %ro!ps and hydroxyl %ro!ps are capa"le o hydro%en "ondin%

    interactions +ith +ater molec!les d!e to the presence o polar 4H and OH "onds

    respecti,ely. The reason +hy phenol is more sol!"le in +ater is d!e to the %reater

    electrone%ati,ity o oxy%en compared to nitro%en.The OH "onds are more polar and the

    hydro%en "ondin% interaction +ith +ater is %reater.

    .

    OH

    O

    ;rom let to ri%ht< car"oxylic acidand alene

    Oleic acid & a atty acid that is a ma=or component o oli,e oil. Can yo! explain +hy

    it is no+n as an !nsat!rated atty acid>

    4CH3

    OH

    CH3

    H

    ;rom let to ri%ht

  • 8/12/2019 PEC140 SB12 Tutorial Answers

    4/5

    C

    CHOH

    OH3C

    H3C

    ;rom let to ri%ht< ether"en#ene rin%7aromatic rin% alcohol (3o) alyne

    /estranol & a component o oral contracepti,es

    O

    Cl

    C

    CH

    :r

    OH

    ;rom let to ri%ht< alcohol (2o) alene

    ether halo%en(:r) halo%en(Cl) alene

    alyne

    O

    O

    CH3

    OH CH2

    O

    H3C

    ;rom let to ri%ht< alene etone alcohol

    (2o) alene ester

    * toxic compo!nd synthesised "y the sea

    hare to eep predators a+ayThe anticancer dr!% AhelenalinB

    $.

    Structure IUP#C &!me

    OH

    O

    3-ethyl-2-methylhexanoic acid

    C CCH3 C

    O

    CH3

    pent-3-yn-2-one

    '

  • 8/12/2019 PEC140 SB12 Tutorial Answers

    5/5

    CH2

    CCH3O

    O

    CH2CH3

    ethyl propanoate

    CH2

    CH2CH2

    CH

    O

    :r '-"romo"!tanal

    '-ethyl-25-dimethylheptane

    5