REACTIONS OF ORGANIC SUBSTANCES

Transcription

1 credits REACTINS F RGANIC SUBSTANCES This activity assesses: Unit:6344 Investigate the characteristic properties and reactions of organic substances (Level 3). Element: 1 Recognise different forms of stereoisomerism. Element: 2 Recognise the reactions of functional groups. Element: 3 Describe the characteristic nature of condensation reactions. CNDITINS: Formal activity. INSTRUCTINS: Task 1A Isomerism 1 Draw the structures of the following molecules and state which of them exist as geometrical isomers. Draw and name these isomers as cis or trans. (a) but-1-ene (b) but-2-ene (c) methylpropene (d) 2,3-dimethylbut-2-ene (e) 1-bromo,1,2-dichloroethene 1.1

2 6.188 SAMPLE ASSESSMENT ACTIVITIES AND SCEDULES UNIT 6344: SAMPLE ACTIVITY 37 2 Which of the following structures exhibit optical isomerism. For those that you have identified as optically active, circle the asymmetric carbon (chiral centre). 1.2 Task 2A rganic reactions 1 State the reactants you would use and any conditions necessary to convert: (a) propan-1-ol propanoic acid Reactant: Conditions (b) ethanol ethyl ethanoate Reactant: Conditions (c) 2-methylpropan-2-ol 2-chloro, 2-methylpropane Reactant: Conditions (d) 1-bromopropane 1-aminopropane NEW ZEALAND QUALIFICATINS AUTRITY - ALL RIGTS RESERVED ASSESSMENT GUIDE: CEMISTRY - JUNE 1997

3 credits Reactant: Conditions 2 Name and draw the structure of the organic product of the following reactions. (a) propanoyl chloride + ammonia (b) aminoethane + hydrochloric acid (c) butanoic acid + S 2 (thionyl chloride) (d) propan-2-ol + acidified potassium dichromate Task 3A Polymers (a) Draw a section of the polymer formed from the following two monomers C (C 2 ) 8 C N 2 (C 2 ) 6 N 2 (b) Why is it classified as a condensation polymer? (c) What is the general name for this group of condensation polymers?

4 6.190 SAMPLE ASSESSMENT ACTIVITIES AND SCEDULES UNIT 6344: SAMPLE ACTIVITY 37 2 Draw the structures of the three amino acids formed when the following tripeptide is hydrolysed. N 2 N C 3 N C 2 S The two structures (a) and (b) are fragments of condensation polymers. For each: (i) (ii) classify the polymer as protein, nylon, polyester or polysaccharide draw the structure(s) of the monomer(s) from which it is made. a) C C C 2 C 2 C C C 2 C 2 assification: Monomer(s) NEW ZEALAND QUALIFICATINS AUTRITY - ALL RIGTS RESERVED ASSESSMENT GUIDE: CEMISTRY - JUNE 1997

5 credits b) C 2 C 2 C 2 assification: Monomer(s) 4 3 (b) is a simplified structure for cellulose. ow does this structure differ from that of starch? 3.2

6 6.192 SAMPLE ASSESSMENT ACTIVITIES AND SCEDULES UNIT 6344: SAMPLE ACTIVITY 37 Task 2B Identification of organic compounds You are given five bottles labelled A, B, C, D, and E, each containing a colourless liquid. The liquids are known to be one of 2-methylbutan-2-ol, propanal, ethanoic acid, aminobutane. You are provided with: universal (indicator) test paper Lucas reagent Tollens' reagent. Using only these test reagents, positively identify each of the five solutions. State your method, observations and conclusions for each test. Write an equation for each of the reactions that confirms the identity of a liquid. 2.2 NEW ZEALAND QUALIFICATINS AUTRITY - ALL RIGTS RESERVED ASSESSMENT GUIDE: CEMISTRY - JUNE 1997

7 UNIT 6344: SAMPLE ACTIVITY 36 SAMPLE ASSESSMENT ACTIVITIES AND SCEDULES Assessment Schedule: Isomerism Unit Standard 6344 Task Number Element and Performance Criteria Evidence (The answers or performance expected from the students) Judgement (A statement that defines the standard to be achieved) 1A (b) and (e) show geometrical isomerism C 3 C 2 2 C 3 C 3 C 3 C 2 3 (a) (b) (c) C 3 C 3 Four structures correctly drawn. Both (and only) (b) and (e) must be correctly identified as showing geometrical isomerism. C 3 C 3 (d) (b) C 3 C 3 cis-but-2-ene (e) Br cis-1-bromo,1,2-dichloroethene Br (e) C 3 C 3 trans but-2-ene Br trans 1-bromo,1,2-dichloroethene Geometrical isomers should be marked consistent with the drawn structures (a) to (e). All must be correctly identified from structures. 1A b), d), and e) are optically active Two optically active isomers are correctly identified with each chiral centre correctly circled. 2A, (a) potassium dichromate (acid conditions) (b) ethanoic (acetic) acid (conc sulfuric acid catalyst & heat) (c) Lucas reagent (Zn2/conc. ) Three conditions/reactants correct. (d) ammonia solution ASSESSMENT SCEDULE: ISMERISM PAGE 1/2 NEW ZEALAND QUALIFICATINS AUTRITY - ALL RIGTS RESERVED ASSESSMENT GUIDE: CEMISTRY - JUNE 1997

8 6.194 SAMPLE ASSESSMENT ACTIVITIES AND SCEDULES UNIT 6344: SAMPLE ACTIVITY 36 2A, 2 (a) C 3 C2 C N 2 propanamide (b) + C 3 C 2 N 3 ethylammonium chloride (c) C 3 C 2 C 2 C butanoyl chloride (d) C 3 CC 3 propanone Three formulae correct. Three names correct. Correct name matched to an incorrect formula does not count. 3A (a) C (C 2 ) 8 C N (C 2 ) 6 N C (C 2 ) 8 C N (C 2 ) 6 N (b) because as each peptide link forms a small molecule (in this case ) is formed. (c) it is a polyamide or nylon All answers correct. 3A Two correctly drawn. N 2 N 2 C 3 C 2 S N 2 3A (a) i) polyester ii) C 2 C 2 (b) i) polysaccharide ii) 3 (a) (i) and 3 (b) (i) correct. Two out of three monomers correctly drawn. Accept simpler form for glucose chair form not required. C 2 3A In cellulose the glucoside links alternate above and below plane of the chair. In starch they are all on the same side. Statement in agreement with that stated. ASSESSMENT SCEDULE: ISMERISM PAGE 2/2 NEW ZEALAND QUALIFICATINS AUTRITY - ALL RIGTS RESERVED ASSESSMENT GUIDE: CEMISTRY - JUNE 1997

9 UNIT 6344: SAMPLE ACTIVITY 36 SAMPLE ASSESSMENT ACTIVITIES AND SCEDULES B 2.2 The one that turns moist litmus red is ethanoic acid. C 3 C C 3 C Four solutions correctly identified with appropriate equations The one that turns moist litmus blue is aminobutane. C 3 (C 2 ) 3 N C 3 (C 2 ) 3 N The one that gives a silver mirror with Tollens' reagent is propanal C 3 C 2 C + Ag + C 3 C 2 C + Ag The one that gives a cloudiness with Lucas reagent is 2-methylbutan-2-ol C 3 C 3 C 3 C C 2 /Zn 2 C 3 C C 2 The one that gives no positive reaction with any of the above reagents (tests) is ethanol. ASSESSMENT SCEDULE: ISMERISM PAGE 1/2 NEW ZEALAND QUALIFICATINS AUTRITY - ALL RIGTS RESERVED ASSESSMENT GUIDE: CEMISTRY - JUNE 1997