CHEMISTRY 2.5 An assessment for AS90309 Describe the structural formulae and reactions of compounds containing selected organic functional groups. Credits: Four INSTRUCTIONS Answer ALL questions. © New Zealand Institute of Chemistry 2007 2 You should spend about 45 minutes on this assessment QUESTION ONE: In the structure of the p-Coumaric acid molecule shown below, three different structural groups have been circled. O A H H C C C B HO OH C On the table below name each functional group Group circled A B C Name of functional group 3 QUESTION TWO: Complete the table below by writing the correct systematic (IUPAC) name for each compound. Compound Structural formula Name of compound O A CH3 CH2 C OH B O CH3 CH2 CH2 C OCH3 C CH3 CH2 CH CH3 OH D CH3 CH3 CH CH CH CH2 CH2 QUESTION THREE: The condensed structural formula of the compound 1,2-dibromopropene is CH3CBr=CHBr . (a) Give the structural formula of the cis and trans isomers of this compound in the boxes below. cis1,2-dibromopropene trans1,2-dibromopropene 4 (b) The two other isomers of dibromopropene are 1,1-dibromopropene and 1,3 dibromopropene (i) Draw the structural formula for the isomer which cannot exist as cis-trans isomers. (ii) Discuss the requirements for cis-trans isomerism using the isomers of dibromopropene from (b) (i) above to illustrate your answer. 5 QUESTION FOUR: (a) Draw structural formulae for the named compounds in the table below. Name of compound A pent-2-ene B 4-chloropentan-1-ol C 3-methylbutanoic acid D 2-methylpropan-2-ol (b) Classify compound D, from the table above, as a primary, secondary or tertiary alcohol by circling your choice below: Primary (c) Structural formula Secondary Tertiary Describe a chemical test that would distinguish between compounds B and C. Include in your answer: the name of the reagent to be used a description of the tests and the expected observations for each compound. _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ 6 QUESTION FIVE: Propene, CH3CH=CH2, undergoes a number of reactions. (a) Reaction with hydrogen: Write the equation of the reaction of propene with hydrogen (b) Reaction with HCl In the boxes below draw the structural formula of the major and minor products of the reaction of propene with HCl. Major product (c) Minor product Reaction with MnO4– In the box below draw the structural formula of the product of the reaction of propene with MnO4- and name it. Name____________________________________ (d) Polymerisation: In the box below draw a section of the polymer formed from propene. Show at least two repeating units. 7 QUESTION SIX: (a) For the following reactions, write the structural formula of the organic product. O (i) CH3 C NaOH OH (ii) CH3 CH2 OH Conc. H2SO4 Heat O (iii) CH3 CH2 OH + CH3 C Conc. H2SO4 OH (b) Heat Identify the type of reaction occurring in each of the three reactions in (a). Select the type of reaction from the list below. addition elimination oxidation-reduction acid-base ester formation substitution (i)__________________________ (ii)_________________________ (iii)________________________ (c) Both ethane and ethene will react with aqueous bromine (Br2). Discuss why reaction with Br2 can be used to distinguish between these two compounds. In your answer include: the reaction conditions needed the observations made the type of reaction that occurs equations for any reactions which occur the names of any product(s) formed _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ 8 QUESTION 7: Fats and oils are tri-ester molecules. Hydrolysis of a fat can be represented by the equation below: CH2 O C C17H35 CH O O C C17H35 CH2 O O C + 3 NaOH 3Na O C C17H35 O C17H35 O (a) Circle an ester linkage. (b) In the box below draw structural formula of compound X. + Compound X 9 QUESTION EIGHT: Complete the flow chart below by drawing structural formulae for the compounds A, B, C, D and E giving the IUPAC names for the compounds A, B, C, and D identifying reagent F. A CH3CH2CH2CH2OH Name__________________ Reagent G B C4H8 Name__________________ H2SO4/H2O H2SO4/H2O C D Name__________________ Name__________________ Reagent H E C and E react Name__________________ Reagent J F C4H8O2