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Organic Chemistry and Alkanes

VIEWS: 108 PAGES: 34

  • pg 1
									   LEVEL 3 CHEMISTRY

3.5 REVISION BOOKLET 2009




            1
                                                   Alkanes
Question 1:
Give (i)        empirical       (ii)       molecular     (iii)     structural formulae for:

   (a) 2-methylbutane                      b) 3-ethyl-2,4-dimethylhexane

         (i)    ________________           i) ______________________

         ii)    ________________           ii) ______________________

         iii)                                            iii)




Question 2:
Give the constitutional formulae for the following:
   (a) 2,3-dimethylbutane                     b)    2,2-dimethylhexane

   _____________________________                  _____________________________

Question 3:
Explain why methylpropane does not need to be written ‘2-methylpropane’.

__________________________________________________________________

__________________________________________________________________

Question 4:
Give IUPAC names for each of the following.

   (a) (CH3)2CHCH2CH3           _________________

   (b) (CH2)4                   _________________
                                                                              H        H
   (c)                                            (d)
                                                                                  C
                     H                 H                            H                           H
                                                                          C                C
                H           C              H                         H                          CH3
                      C           C                                   H       C       C        H
                H                          H
                                                                              H       CH3
                    ________________                             ________________

                                                        2
Question 5:
Calculate the empirical and molecular formulae for the following compounds:
   (a) a hydrocarbon with 83.3% carbon and 16.7% hydrogen

   __________________________________________________________________

   __________________________________________________________________

   __________________________________________________________________

   b) a hydrocarbon with 90% carbon

   __________________________________________________________________

   __________________________________________________________________

   __________________________________________________________________

   (b) an organic compound with 40% carbon, 6.7% hydrogen, 53.3% oxygen with a molar mass of 60
       g mol-1

   __________________________________________________________________

   __________________________________________________________________

  __________________________________________________________________
Question 6:
  (a) Give the names, constitutional and structural formulae for the three structural isomers of C5H12.

   1) __________________________________________________________________

   2) __________________________________________________________________

   3) __________________________________________________________________

   (b) Suggest which isomer of C5H12 will have the lowest boiling point and explain why.
   __________________________________________________________________

   __________________________________________________________________


Question 7:
Write the constitutional formulae and name the five isomers of C6H14.




                                                   3
Question 8:
Why are cycloalkanes not isomeric to alkanes?
   __________________________________________________________________
   __________________________________________________________________
Question 9:
Name (i) the type of intramolecular bonding and (ii) the type of intermolecular bonding in:
a) methane gas
   ___________________________________________________
_____________________________________________________________________

b) liquid pentane     ___________________________________________________
_____________________________________________________________________
Question 10:
Explain in terms of bonding why:
   (a) methane gas can be collected over water
   __________________________________________________________________
   _________________________________________________________________

   (b) petrol floats on water. (Mention solubility of petrol in water and relative densities in your
       answer).
       _________________________________________________________________
       __________________________________________________________________

   (c) Oil dissolves in petrol forming a mixture called ‘2-stroke’.
   __________________________________________________________________
   __________________________________________________________________
Question 11:
Explain why CNG used for gas barbeques must be stored in a heavy mental metal container whereas
LPG cigarette lighters are made of thin plastic.

   __________________________________________________________________

   __________________________________________________________________
Question 12:
Explain why neither solid nor liquid cyclohexane conducts electricity.

   __________________________________________________________________

   __________________________________________________________________



                                                    4
                                                Alkenes

Question 1:
Name the type of intramolecular and intermolecular bonding in:
  (a) ethene gas      _____________________________________
  (b) liquid pentene _____________________________________

Question 2:
Explain in terms of bonding why ethane gas can be collected over water.




Question 3:
Cyclohexene floats on water. What can be deduced about:
   (a) the solubility of cyclohexene __________________________________________
   (b) the density of cyclohexene __________________________________________

Question 4:
Explain why neither solid nor liquid pentene conducts electricity.




Question 5:
Consider the following alkenes:
(i) 2-methylbut-1-ene    (ii) pent-1-ene   (iii) hex-3-ene   (iv) 2-methylpent-2-ene

   (a) Which can exist as cis and trans isomers? ______________
   (b) Which are structural isomers of cyclohexane C6H10? ______________

Question 6:
Give the names of five isomers of C4H8. Identify the types of isomerism invlolved.




Question 7:
For the following two compounds:
(i) (CH3)2C=CHC2H5 (ii) CH3CH=CHC2H5

   (a) Name them.    (i) ________________
                     (ii) ________________
   (b) Give their molecular formulae.      (i) ________________
                                           (ii) ________________
   (c) Which can exist as geometric isomers?       (i) YES / NO (ii) YES / NO



                                                   5
   (d) Draw and name the two geometric isomers.




Question 8:
  (a) What is an addition reaction?

   (b) Using structural formulae show the reaction between ethane C2H4 and water.




Question 9:
Name and draw the product of the reactions with 1-butene with:
  (a) bromine




   (b) hydrogen




Question 10:
  (a) What molecule is involved in the following reactions:

     (i) hydrogenation ________ (ii) bromination _________ (iii) hydration _________

   (b) Name the catalysts and conditions needed for each of the reactions above.
     (i) __________________ (ii) __________________ (iii) __________________




                                                  6
Question 11:
Name and draw the main organic product formed when propene is reacted with hydrogen chloride.




Question 12:
Name and draw the main organic product formed when 2-mthylpent-2-ene is reacted with water.




                                                7
                                               Alcohols

Question 1:
Give the :
   (a) molecular and structural formulae of propan-1-ol     ________________________




   (b) constitutional formula for butan-2-ol ________________________
   (c) constitutional formula for 2-methylpropan-2-ol     ________________________
   (d) molecular and constitutional formulae for 3-methylpentan-3-ol


Question 2:
(a). propan-1-ol   (b) butan-2-ol   (c) 2mthylpropan-2-ol    (d) 3-methylpentan-3-ol

Which two of the above alcohols are isomeric with each other? __________________

Question 3:
Why does 1-propanol (M is 60 g mol-1) have higher melting and boiling points than butane (M is 58 g
mol-1), despite the fact that both have a similar molecular mass?

   __________________________________________________________________

   __________________________________________________________________

Question 4:
Why does the solubility of alcohols in water decrease as the molar mass of the alcohol increases?

   __________________________________________________________________

   __________________________________________________________________
Question 5:
Ethanol will dissolve in:
       (i) water (ii) hexane
For both solutions:
   (a) draw diagrams showing the intermolecular forces between one molecule of each substance.
   (b) Name and show the position of the intermolecular bonds.


     (a) _____________________                  (a) _____________________
     (b)                                        (b)



                                                      8
Question 6:
Esters are sweet smelling volatile organic compounds containing oxygen but no hydroxyl groups.
Many perfumes contain naturally occurring esters dissolved in ethanol (b.p. 78.6oC). Give two reasons
why ethanol is a more suitable solvent than water for perfumes.

   __________________________________________________________________
   __________________________________________________________________
   __________________________________________________________________

Question 7:
Explain why sodium chloride NaCl dissolves in ethanol to form a solution that conducts electricity.

   __________________________________________________________________
   __________________________________________________________________
Question 8:
  (a) Classify each of the following as a primary, secondary or tertiary alcohol
      (i) ethanol __________                     (ii) butan-2-ol __________
      (iii) pentan-3-ol __________               (iv) 2-methylbutan-2-ol __________
      (v) pentan-1-ol __________                 (vi) 3-methylbutan-2-ol __________
                                               2
      (vii) 2 methylepropan-2-ol __________ (viii) 3-methylpentan-3-ol __________
  (b) Which of the above are isomers? __________________
Question 9:
  (a) Name and classify each of the following as primary, secondary or tertiary alcohols:
           (i)    CH3CH2CH2OH                __________________________
           (ii)   CH3CHOHCH2CH2CH3 __________________________
           (iii)  CH3COH(CH3)CH3             __________________________
           (iv)   CH3CH(CH3)CH2OH            __________________________
           (v)    CH3CH(CH3)CHOHCH3 __________________________
  (b) Identify from the above those which form optical isomers. Rewrite their constitutional formula
      and place an asterisk (*) against the asymmetric carbon atom.

   __________________________________________________________________

   __________________________________________________________________

Question 10:
Two structural isomers of C4H10O are primary alcohols. Give their:

   (a) Names ______________________         ______________________

   (b) Constitutional foumlae _______________________ _______________________

Question 11:
−CH2OH is the characteristic arrangement of atoms in primary alcohols. What is the characteristic
arrangement of atoms in:

secondary alcohols? _________________                  tertiary alcohols?   ___________________
                                                   9
Question 12:
  (a) Explain why cyclohexanol C6H11OH is classified as a secondary alcohol.

   __________________________________________________________________

   __________________________________________________________________


   (b) Draw and name one simple isomer of cyclohexanol that is classified as a tertiary cyclic alcohol.




Question 13:
Identify the reagents and give the conditions needed to convert:

   (a) ethanol to ethanoic acid      __________________________________________

   (b) propan-2-ol to propene        __________________________________________

   (c) 2-methylbutan-2-ol to 2-chloro-2-methylbutane

       __________________________________________________________________

Question 14:
Name the products and give the equation for the reactants of:
  (a) 2-methylpropan-2-ol with Lucas reagent

   __________________________________________________________________

   __________________________________________________________________

   (b) 2-methylbutan-2-ol with concentrated sulfuric acid at 170oC

   __________________________________________________________________

   __________________________________________________________________




                                                   10
Question 15:
For the oxidation of ethanol to ethanoic acid by acidified potassium permangenate:
   (a) give an ion-electron half-equation for the oxidation reaction

   __________________________________________________________________

   (b) give an ion-electron half-equation for the reduction reaction

   __________________________________________________________________

   (c) give the overall equation

   __________________________________________________________________

   (d) identify accurately the colour change you would expect to see

   __________________________________________________________________

Question 16:
Compounds A, B, C and D are isomeric alcohols of molecular formula C4H10O of which A has the
lowest boiling point. Only A, C and D react with warm acidified dichromate giving a blue/green
solution. With Lucas reagent, B reacts rapidly whereas C reacts after about 15 minutes (A and D do not
react).
    (a) What test confirms the presence of −OH groups? __________________________
    (b) What is the observation for a positive Lucas test? __________________________
    (c) Name and classify alcohols A to D.
        A:
        B:
        C:
        D:

Question 17:
  (a) Write the constitutional formula for glycerol. _____________________________
  (b) Glycerol can also be called 1,2,3-trihydroxypropane. Explain how this name is consistent with
       the name propan-1,2,3-triol.
__________________________________________________________________
_________________________________________________________________
__________________________________________________________________

Question 18:
Explain why 1-propanol (M = 60 g mol-1) has a boiling point of 97.2oC, but ehtna-1,2,diol (M = 62 g
mol-1) has a boiling point of 198oC.
__________________________________________________________________
__________________________________________________________________
_________________________________________________________________
                                                  11
                                   Haloalkanes (or Alkyl Halides)

Question 1:
  (a) Give the molecular and constitutional formulae for:
      (i)    2-bromobutane         __________________________________________
      (ii)   1,1,1-trichloroethane __________________________________________
  (b) One of the above compounds can exist as optical isomers. Draw the isomers and asterisk (*) the
      asymmetric carbon atom.




Question 2:
Give the constitutional formula and asterisk any asymmetric carbon atoms for the following:
   (a) 2,2-dichlorobutane _______________________________________________

   (b) 2,3,3-trichloropentane _______________________________________________

   (c) 1,2-dibromobutane      _______________________________________________

   (d) 1,3-dibromopropane _______________________________________________

Question 3:
1-bromobutane, 2-bromobutane and 2-bromo-methylpropane are isomers of C4H9Br.
    (a) Classify each as a primary, secondary or tertiary haloalkane

_________________________________________________________

_________________________________________________________

_________________________________________________________


   (b) There is a fourth isomer of C4H9Br.
       (i) write its name and give its structural formula.




                                                   12
       (ii) classify it as a primary, secondary or tertiary haloalkane.



Question 4:
Classify the following haloalkanes as primary, secondary or tertiary:

   (a) (CH3CH2)3C-Cl          _____________________

   (b) Br-CH2CH2CH2-Br        _____________________

Question 5:
The following table shows the molar masses and boiling points of various compounds:
                       Compound            M / g mol-1     Boiling Point / oC
                        chloroethane          64.5                12.3
                           pentane             58                  -0.5
                         1-porpanol            60                 97.2
Explain why the three compounds have different boiling points.
_________________________________________________________

_________________________________________________________

Question 6:
  (a) Draw a diagram of bromoethane showing its polarity




   (b) Is chlororethane more or less polar than bromoethane? Explain your answer.

_________________________________________________________
______________________________________________________
_________________________________________________________
  Question 7:
Name two common haloalkanes and give one use for each.
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________


                                                    13
  Question 8:
  Explain why tetrachloromethane CCl4 contains polar bonds but is a non-polar molecule.
  _________________________________________________________
  ________________________________________________________
  _________________________________________________________

  Question 9:
  Give the reagents, conditions and balanced equations using structural formulae to convert 2-
  chloropropane to:
      (a) 2-aminopropane




      (b) propene




      (c) 2-propanol




  Question 10:
  Why does chloroethane undergo substitution reactions:
    (a) more readily than ethane
    _________________________________________________________
         _______________________________________________________
  _______________________________________________________
b) more readily than bromoethane
  _________________________________________________________
  _________________________________________________________
  ________________________________________________________
                                                    14
Aminoalkanes (or Amines)

Questions 1:
  (a) Give the constitutional and the structural formulae for:
          (i)    aminomethane                ____________________




              (ii)      2-aminopentane      ____________________




              (iii)     1,4 diaminobutane   ____________________




   (b) For those above that form optical isomers, asterisk (*) the asymmetric carbon atom.

Question 2:
  (a) Classify each of the following as primary, secondary or tertiary aminoalkanes:
    (i)         H H H CH3                     (ii)        H H H C2H5
                | | | |                                   | | | |
            H − C − C − C − N − CH3                   H−C−C−C−N−H
                | | |                                     | | |
                H H H                                     H H H

                ____________________                  ____________________

      (iii)            H H H H H     (iii)                H H H C2H5
                       | | | | |                          | | | |
                     H−C−C−C−C−C−N−H                  H − C − C − C − N − CH3
                       | | | | | |                        | | |
                       H H H H H H                        H H H

                     ____________________             ____________________




                                                 15
Question 3:
Classify the following as primary, secondary or tertiary aminoalkanes:
(a) (CH3CH2)3C-NH2 ______________ (b) CH3-NH-CH2-C(CH3)3 ______________

Question 4:
Name the following:
(a) CH2CH(NH2)CH3 __________________ (b) CH3(CH2)5NH2 __________________
(c) CH3C(NH2)(CH3)(CH2)2CH3 __________________

Question 5:
                           Compound               M / g mol-1        b.p. / oC
                           aminoehtane                  45             16.6
                              ethanol                   46             78.6
                             propane                    44              -42
Using the data from the table above:
   (a) Explain the difference in boiling points (b.p.) between aminoethane and propane.




   (b) Explain the difference in boiling points between aminoethane and ethanol.




Question 6:
Why does the solubility of aminoalkanes in water decrease as the molecular mass of the aminoalkane
increases?




Question 7:
CH3N(CH3)2 and C3H7NH2 are structural isomers:
  (a) name both _________________________________________________________
  (b) explain which would have the highest m.p.




Question 8:
Give equations for the reactions of aminomethane CH3NH2 with:
   (a) water                          __________________________________________
   (b) hydrochloric acid              __________________________________________
   (c) aqueous copper (II) ions       __________________________________________
Question 9:
For each reaction in Question 1 write the equivalent reaction with ammonia:
   (a) __________________________________________
   (b) __________________________________________
                                                 16
   (c) __________________________________________

Question 10:
Complete the equation: 2CH3CH2NH2 + H2SO4             ___________________________

Question 11:
Explain why:
   (a) aqueous aminoehtane is an alkaline solution




   (b) lemon juice and vinegar are often used on cooked fish




Question 12:
Explain why, on adding aqueous aminoethane to copper sulfate solution:
   (a) initially, a light blue precipitate is seen




   (b) with excess aqueous aminoethane the light blue precipitate dissolves to form a deep blue
       coloured solution.




                                                 17
                                       Aldehydes and ketones

Question 1:
Draw the formulae indicated in brackets for each of the following compounds:
   (a) methanal (structural)                 (b) hexan-2-one (structural)




   (b) 2-methylpentanal (molecular and structural)


                                            Formula: ____________________________




   (c) 3-methylpentan-2-one (constitutional and structural)


                                            Formula: ____________________________




Question 2:
Two structural isomers of C4H8O are aldehydes and one is a ketone.. For each of these three
compounds write the IUPAC name and give the constitutional formula.


   (a) Name: ____________________           Formula:


   (b) Name : ____________________          Formula:


   (c) Name : ____________________          Formula:

Question 3:
Give the conventional name and constitutional formula of:

   (a) Acetone               ________________________________________________

   (b) Acetaldehyde          ________________________________________________



                                                  18
Question 4:
Name:          CH3CH2CH2 − C − CH3            ____________________________________
                                   O
Question 5:
Why do aldehydes have higher melting and boiling points than alkanes of similar molecular mass?
____________________________________________________
____________________________________________________

Question 6:
   (a) Explain why the solubility of aldehydes in water decreases as the molecular mass of the
       aldehyde increases.
____________________________________________________
____________________________________________________

   (b) Would you expect the solubility of ketones to decrease in the same way?
____________________________________________________
____________________________________________________

Question 7:
Discuss with reasons the differences in the boiling points (b.p.) of:
       ethanol (M = 46 g mol-1), b.p. =78oC, and
       ethanal (M = 44g mol-1) b.p. = 21oC
____________________________________________________
____________________________________________________

Question 8:
During the laboratory preparation of propanal from propan-1-ol:

   (a) what is the most likely impurity in the product?       ________________________

   (b) how are the products separated?       ____________________________________
   (c) why is there no similar impurity during the production of propanone from propan-

   2-ol?       ____________________________________________________

Question 9:
Why is ethanal easily separated from an original reaction mixture of ethanol and acidified potassium
dichromate?

       ____________________________________________________

       ____________________________________________________


                                                    19
Question 10:
Give the constitutional formulae and names of the alcohols used to prepare:

   (a) CH3CH2CHO              _______________________________________________

   (b) CH3CH2COCH3            _______________________________________________

   (c) CH3CH(CH3)CHO          _______________________________________________

Question 11:
When Tollens’ reagent oxidises ethanal to ethanoic acid, an ion is the oxidant. For this ion, give:
  (a) its name and formula:         __________________________________________

   (b) the colour change observed: __________________________________________

   (c) the reduction half-equation: __________________________________________

Question 12:
When Benedct’s solution oxidizes ethanal to ethanoic acid, an ion is the oxidant. For this ion, give:
  (a) its name and formula:         __________________________________________

   (b) the colour change observed: __________________________________________

   (c) the reduction half-equation: __________________________________________

Question 13:
Acidified potassium dichromate will oxidize ethanal to ethanoic acid. For acidified potassium
dichromate, give:
    (a) name and formula of oxidizing species: ________________________________

   (b) the colour change observed: __________________________________________

   (c) the reduction half-equation: __________________________________________

Question 14:
Aqueous silver nitrate (a few mL) is placed in a clean test tube and 1 drop of NaOH is added. The
precipitate that forms is dissolved by adding just enough dilute ammonia.

   (a) name the reagent that has been prepared above:     ________________________
   (b) describe what is observed when this reagent is warmed with a few drops of each of the
       following:
       (i)    butanone       ___________________________________________

       (ii)    butan-1-ol     ___________________________________________

       (iii)   butanal        ___________________________________________




                                                    20
Question 15:
  (a) When an aldehyde reacts with Fehling’s solution, does the aldehyde undergo oxidation,
      reduction, substitution, addition, hydrolysis or elimination?

       _____________________________
   (b) What is the original colour of Fehling’s solution and what species is responsible

   for this? ____________________________________________________
   (c) What is the precipitate that is formed in the Fehling’s test, and what colour is it?
   (d)
       ____________________________________________________




                                                    21
                                        Carboxylic Acid Derivatives

Question 1:
Complete the following equations:
  (a) CH3CH2-COCl + CH3OH                      ____________________________________

   (b) CH3CH2-COCl + CH3NH2                    ____________________________________

Question 2:
  (a) Name:
      (i) HCOCl _______________ (ii) C3H7COCl _________________

   (b) Give the constitutional formulae for:

       (i) ethanoyl chloride ____________________

       (ii) 2-methylbutanoyl chloride ____________________

Question 3:
Name the substances which react with propanoyl chloride to form:
  (a) propanamide C2H5CONH2 ___________________________

   (b) methylpropanoate C2H5COOCH3 ___________________________

   (c) N-methylpropanamide C2H5CONHCH3 ___________________________

   (d) Propanoic acid C2H5COOH ___________________________

Question 4:
Name:
(a) CH3CH2COOCH3 _____________ (b) CH3COOC3H7 _______________




Question 5:
Draw structural formulae for:
(a) methyl ethanoate                             (b) propyl ehtnaoate




Question 6:
Complete the following hydrolysis reactions:
  (a) CH3 − CO − OCH2CH2CH3 + NaOH                     _____________________________


                                                        22
   (b) CH2O − OC(CH2)16CH3
        |
       CHO − OC(CH2)16CH3 + 3NaOH                    ______________________________
        |
       CH2O − OC(CH2)16CH3
Question 7:
Explain what is meant by the terms:
   (a) esterification

_________________________________________________________

   (b) condensation reaction

_________________________________________________________


   (c) hydrolysis

_________________________________________________________

   (d) reflux

_________________________________________________________

Question 8:
Complete the following equation:
CH3CONH2 + KOH              _________________________________

Question 9:
Complete the following equations:
  (a) CH3COCl + NH3              _________________________________

   (b) CH3COOC2H5 + NH3                 ________________________________
Question 10:
For each of the following draw their structures and then identify each as primary, secondary or tertiary amides:
   (a) propanamide                           (b) N-ethyl-N-methylpropanamide




   (a) N-ethylethanamide




                                                       23
Question 11:
Name the amides of molecular formula C3H7ON, and state whether they are primary, secondary or tertiary
amides.

_________________________________________________________

_________________________________________________________

_________________________________________________________


Question 12:
Give balanced equations and name the reagents needed to prepare the following:
   (a) N-methylethanamide


   (b) N,N-dimethylpropamide




Question 13:
Aminoethanoic acid (glycine) and aminopropanoic acid (alanine) are two simple amino acids.
  (a) Draw their structural formulae




   (b) What is meant by the term asymmetric carbon?

_________________________________________________________

_________________________________________________________

   (c) Indicate any asymmetric carbon atom present by an asterisk (*) on the asymmetric carbon.
   (d) What type of isomerism is caused by the presence of asymmetric carbon atoms?

      _________________________
Question 14
Show the structural formula of a typical amino acid using ‘R’ for the side chain.



                                                       24
Question 15:
What feature would you look for in deciding whether a compound rotates the plane of polarized light? Illustrate
your answer by referring to α-alanine and β-alanine:
               2-aminopropanoic acid            3-aminopropanoic acid
                     α-alanine                        β-alanine

            H2N − CH − COOH         H2N − CH2CH2 − COOH
                  |   .
                  CH3 .
_________________________________________________________

_________________________________________________________

Question 16:
Describe briefly the differences, if any, between the two optical isomers of an amino acid as alanine with
respect to the following:
    (a) their effect on polarized light

_________________________________________________________

   (b) their solubility in water

_________________________________________________________
   (c) their occurance in natur ____________________________________________________
                                                     Polymers

Question 1:
Saran, a useful polymer, has the structure:
- - - CH2 — CCl2—CH2 — CCl2—CH2 — CCL2- - -
From what monomer is it made? ___________________________

Question 2:
1,1-dichloroethane CH2=Cl2 undergoes addition polymerization. Draw the structure of a section of the polymer
chain containing at least two monomer units.




                                                       25
Question 3:
  (a) What do the conventional names of addition polymers have in common?

   (b) What functional group is common to the monomers of addition polymers?


Question 4:
  (a) Which properties of PVC makes it useful as:
      (i) _____________________________ (ii) _____________________________
      (iii) ____________________________ (iv) _____________________________
  (b) Why do plastics like polyvinylchloride cause pollution?



Question 5:
Choose two polymers other than PVC and explain their uses in terms of their properties.




Question 6:
  (a) What is a condensation reaction?




   (b) What is an elimination reaction?




Question 7:
Name two common substances eliminated during condensation reactions.


Question 8:
  (a) Name the monomers required to produce terylene.

   (b) Draw the two forms of the ester linkage found in terylene.




                                                      26
   (c) Draw one repeating unit from a terylene polymer.




Question 9:
  (a) When was nylon first used commercially? ________________
  (b) What was nylon a replacement for? _______________

Question 10:
Give two uses of nylon and explain these uses in terms of the properties of nylon.


Question 11:
Nylon 5,5 is made from two monomers, pentanedioic acid and 1,5-diaminopentane.
   (a) Draw structural formulae for these two monomers.




   (b) Give the formula for one repeating unit of the polymer.




   (c) Draw two forms of the linkage between the monomer units.




                                                       27
   (d) Suggest names for the monomers required to make nylon 5,8.

   (e) Name a possible amino acid monomer.


Question 12:
What is the relationship between proteins, amino acids, polypeptides and dipeptides?




                                                      28
Question 13:
Draw the structural formulae for the two possible dipeptides formed from aminoethanoic acid (glycine
H2NCH2COOH) and 2-aminopropanoic acid (alanine, CH3NH(NH2)COOH).




Question 14:
Why is it impossible to draw a repeating unit for a protein?



Question 15:
A portion of a protein molecule is drawn below:
                           CH3             CH2OH       H
                           |                |          |
                        — C — C — N — CH — C — N — CH —
                                o||   o|        o|| o|
                           o    O     H       o O   H

Hydrolysis of the portion shown will yield three amino acids: glycine, alanine and serine.
   (a) What is meant by the term ‘hydrolysis’?

   (b) Give one condition under which hydrolysis of the protein could occur.

   (c) Draw the structure and name the amino acid containing the hydroxyl group.




Question 16:
Why can animals digest starch more easily than cellulose?




Question 17:
Aqueous hydrochloride acid HCl and aqueous sodium hydroxide are used to hydrolyse peptide links.
   (a) Acid hydrolysis using HCl(aq) of the peptide link in N-methylethanamide CH3CONHCH3 produces a
       carboxylic acid and methylamine hydrogen chloride CH3NH3Cl. Give a balanced equation for the
       reaction.
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   (b) Give the balanced equation for the alkaline hydroysis of N-methylethanamide CH3CONHCH3.




                                      Organic Reactions Summary

Question 1:
Give the expected colour changes for two named reagents which would oxidize:
   (a) both alcohols and aldehydes __________________________________________


   (b) aldehydes but not alcohols   __________________________________________



                                                  30
Question 2:
Sulfur(IV) oxydichloride (thionyl chloride SOCl2) is used as a chlorinating agent in organic reactions.
   (a) What group is replaced by a chlorine atom during chlorination? ______________
   (b) Is this a substitution, addition or elimination reaction? ______________________
   (c) Write a balanced equation for the reaction of SOCl2 to form:
        (i) chloroethane CH3CH2Cl
            _______________________________________________________________
         (ii) ethanoyl chloride CH3COCl
            _______________________________________________________________
   (d) Name and give the formula of one other chlorinating agent.


Question 3:
Potassium hydroxide can be used both in substitution and elimination reactions involving 2-chlorobutane.
   (a) Give the equations for:
       (i) the substitution reaction
            _______________________________________________________________
            _______________________________________________________________
       (ii) the elimination reaction
            _______________________________________________________________
            _______________________________________________________________
       Specify the conditions needed for each reaction
   (b) The elimination reaction produces three isomeric products. Name them.

Question 4:
For the following pairs of chemicals, name the chemical reagents used to distinguish them and give the
expected colour changes.
   (a) ethanol and ethanoic acid

   (b) pentane and 1-pentene


   (c) propanol and propanone

   (d) hexane and 1-hexanol


Question 5:
Consider the following test reagents used in organic chemistry:
Ag+/NH3 (Tollens’ reagent), H+/Cr2O72-, HCl/ZnCl2 (Lucas’ reagent), Br2 water, water

Select the test reagent that would enable you to distinguish between the following pairs of compounds. State
what you would observe when the test reagent is added to both compounds. (A test reagent may be used more
than once.)
    (a) hex-1-ene and hexane




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   (b) methylpropan-2-ol and butan-1-ol




   (c) propanone and propanal




   (d) chloroethane and ethanoyl chloride.




Question 6:
Imagine that you have found four unlabelled bottles containing colourless liquids that you know to be hexane,
1-hexene, ethanol and ethanoic acid (acetic acid). How would you tell which was which using bromine and an
aqueoussolution of sodium bicarbonate as the only reagents? Describe clearly what you would do and see.




Question 7:
Give the names and constitutional formulae for the compounds a-j which complete the following equations.
   (i)     (a) + CH3CH2OH           C2H5COOC2H5 + (b)            (conc H2SO4 catalyst, warm)
   (ii)    (c) + (d)       CH3CH=CHCH4 + NaCl + H2O
   (iii)   (e) + (f)       (CH3)3CCl
   (iv)    (g) + CH3CH2OH            C2H5COOC2H5 + (h)           (standard conditions, no catalyst)
   (v)     (i)       ─[NH─C5H10─CO]n─ + (j)

                 Name                                 Constitional Formula
           (a)
           (b)
           (c)
           (d)
           (e)
           (f)
           (g)
           (h)
           (i)
           (j)

Question 8:

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Complete the following two step reactions by identifying the reagents and compounds indicated.

                         reagent (b)                  reagent (c)
   (i)        CH3CH2Cl                 compound (a)                 CH3CH2OH

                         reagent (e)                  reagent (f)
   (ii)       CH3COOH                  compound (d)                 CH3CONH2

                         reagent (h)                  reagent (i)
   (iii)      CH3CH2Cl                 compound (g)                 C2H5NHC2H5

                                        Name and Constitutional Formula
                    compound (a)
                    reagent (b)
                    reagent (c)
                    compound (d)
                    reagent (e)
                    reagent (f)
                    compound (g)
                    reagent (h)
                    reagent (i)
Question 9:
Use the constitutional formulae (i)-(iv) to answer the questions which follow:
 (i) C3H7CH=CH2         (ii) C3H7CHOHCH3        (iii) C2H5COOC2H5      (iv) C4H9COCl
   (a) Name (i)-(iv).


   (b)     Which has the empirical formula CH2? _______
   (c)     Which decolourises aqueous bromine (bromine water)? _______
   (d)     Which reacts with NaOH(aq) to produce an alcohol as one of two organic products? _______
   (e)     Which reacts most radily with NH3(aq) to produce an amide? _______
   (f)     Name and draw the structural formula for the organic product when (ii) reacts with (iv)




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Question 10:
The following diagram shows six compounds of which compounds A-E contain two carbon atoms. The diagram
also shows some of the chemical changes these compounds undergo.

                                         COMPOUND A
                                           CH2=CH2

                 reaction with HCl                             reaction with H2O in
                                                               presence of a catalyst

         COMPOUND B                                                           COMPOUND D


    reaction with excess NH3                                             oxidation with acidified dichromate
                                                                        which changes orange to green colour

                                   compound E can react with
        COMPOUND C                Na2CO3 solution to form CO2,
        CH3─CH2─NH2                                                           COMPOUND E
                                    and turns blue lithmus red

                                    reaction due to heating the dried
                                      compounds C and E together

                                          H
                                          |.
                   COMPOUND F CH3 ─ CH2 ─ N ─ C ─ CH3 + COMPOUND G
                                              ||
                                              O
With reference to the flow diagram, complete the following table for compounds A-G.
   Compound                       Formula                           Systematic Name
       A                         CH2=CH2                     (i)
       B            (ii)                                     (iii)
       C                       CH3−CH2−NH2                   (iv)
       D            (v)                                      (vi)
        E           (vii)                                    (viii)
        F                              H                     N-ethyleanamide
                                       |
                          CH3 − CH2 − N − C − CH3
                                            ||
                                           O
       G            (ix)
                                      H
   (a) Name the speical linkage       |             found in F. _______________________
                                     −N−C−
                                        ||
                                        O
   (b) Name one type of important biological molecule that contains this linkage.


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