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Starter - complete the following scheme giving all Formula

Starter - complete the following scheme giving all Formula. H+. Ethanoyl chloride Formula?. CH 3 COOH + C 2 H 5 OH. CH 3 COCl. ethanamide CH 3 CONH 2. NH 3 / ethanol. C 2 H 5 OH. Reagents?. salt + ethanol CH 3 COO - + C 2 H 5 OH. OH-. Ethyl ethanoate Formula?.

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Starter - complete the following scheme giving all Formula

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  1. Starter - complete the following scheme giving all Formula H+ Ethanoyl chloride Formula? CH3COOH + C2H5OH CH3COCl ethanamide CH3CONH2 NH3 / ethanol C2H5OH Reagents? salt + ethanol CH3COO- + C2H5OH OH- Ethyl ethanoate Formula? CH3COOC2H5 C2H5OH + Conc H2SO4 Reagents? Ethanoic acid CH3COOH N-ethylethanamide CH3CONH2C2H5 C2H5NH2 / ethanol

  2. Reactions of Amides • How can you make ethanamide? • ethanoyl chloride and ammonia O O CH3 C CH3 C + NH3 + NH4Cl NH2 Cl ethanoyl chloride + ammonia ethanamide + ammonium chloride

  3. Reactions of amides • draw the full structural formula for ethanamide and H3O+ O O CH3 C CH3 C + H3O+ + NH4+ OH NH2 ethanamide + acid organic acid + ammonium ion

  4. Reactions of amides 2. Basic conditions O O CH3 C CH3 C + OH- + NH3 O- NH2 ethanamide + base conjugate base + ammonia of acid

  5. Synthetic polymers Polyamides Polyamides can be made by combining a ________ and a _____________acid Nylon 6,6 can be made into fibres to make pantyhose or in other forms gear wheels with tough properties Nylon 6,6 is made from _____________ acid and _________________ Draw the structural formula of these two compounds diamine dicarboxylic hexanedioic 1,6 diaminohexane H H HO O N CH2CH2(CH2)4 N CH2CH2CH2CH2C C OH H H O 1,6 diaminohexane hexanedioic acid

  6. Synthetic polymers continued Polyamides Nylon 6,6 is an example of a ____________ polymer condensation 1,6 diaminohexane hexanedioic acid Peptide link O H H O HO HO CH2CH2CH2CH2C N CH2CH2(CH2)3CH2 N C CH2CH2CH2CH2C C O O H OH H Draw the structural formula of nylon 6,6 Water removed means a condensation reaction

  7. Task – write the balanced redox reactions for the oxidation of the oxidation of propan-1-ol to propanal using Cr2072- /H+ and give all colour changes. (X3) 3 CH3CH2CH2OH 3 CH3CH2COH + 2H+ + 6H+ + 6e- + 2e- Cr2072- + 14H+ + 6e- 2Cr3+ + 7H20 Full balanced redox equation 3CH3CH2CH2OH + Cr2072- + 8H+ 3CH3CH2COH + 2Cr3+ + 7H20

  8. The Lucas Test What is the lucas test? The Lucas test is used to distinguish between the 3 types of alcohols What reagents does the lucas test consist of? The Lucas reagent consists of ZnCl2 in concentrated HCl What do you observe ocurring with a positive lucas test? Chloroalkanes form and appear as a cloudy suspension in the water because they are insoluble. 3o then 2o then 1o What is the purpose of the zinc chloride and what kind of reaction occurs The zinc chloride catalyses a substitution reaction between the alcohol and the concentrated HCl

  9. Task – write the balanced redox reactions for the oxidation of the oxidation of propan-2-ol to propanone using Mn04- /H+ and give all colour changes. (X5) 5 CH3CHOHCH3 5 CH3COCH3 + 10H+ + 2H+ + 10e- + 2e- + 10e- (X2) 2MnO4- + Mn04- + 8H+ 16H+ + 5e- 2Mn2+ Mn2+ + 4H20 + 8H20 Full balanced redox equation 5CH3CHOHCH3 + 6H+ + 2Mn04- 5CH3COCH3 + 2Mn2+ +8H20

  10. REDOX 90696 2005 QUESTION ONE: COBALT AND CHROMIUM IN REDOX REACTIONS An electrochemical cell is set up using appropriate electrodes and solutions of potassium dichromate and cobalt(II) nitrate. It is based on the following half-cell reactions: Co2+ + 2e– Co E° = – 0.28 V Cr2O72– + 14H+ + 6e– 2Cr3+ + 7H2O E° = +1.36 V (a) Write a balanced equation for the spontaneous reaction that would occur in the cell. (b) Calculate the E°for the spontaneous reaction in the above cell. (c)Complete the diagram below to show how the electrochemical cell would be set up. On your diagram label the electrodes, the solutions (electrolytes) and indicate the direction of the flow of charge (cations, anions and electrons) between the two half-cells.

  11. 2005 1a. Achieved 3Co + Cr2O72– + 14H+ → 2Cr3+ + 7H2O + 3Co2+ Correct equation. 1b. Achieved Eo cell = E(Cr2O72– /Cr3+ ) – E(Co2+ / Co) = +1.64 V Correct answer. 1c. Pt 1 Evidence Salt bridge drawn connecting half-cells. One half-cell: Co electrode, Co2+ solution Other half-cell: Inert electrode eg Pt electrode, K2Cr2O7 Achieved - Salt bridge shown OR ONE half cell correctly labelled. Merit - ALL aspects of the cell correctly drawn and labelled. 1c. Pt 2 Evidence • e – flow from anode to cathode (Co to Pt) • anion movement toward anode (Co) • cation movement toward cathode (Pt) Achieved - Correct direction for electrons OR one of the ions. Merit - ALL movement of charge correct.

  12. 2005 1(d) Complete the standard cell diagram for this cell. (e) Cobalt is a transition metal that exists in both the +2 and +3 oxidation states.  A piece of cobalt metal is reacted with acidified potassium dichromate solution. Using the relevant reduction potentials, determine if the cobalt ion produced in this reaction is Co2+ or Co3+. E°(Co3+/Co2+) = +1.82 V Achieved Co│Co2+ ║Cr2O72–, Cr3+ │Pt Any inert electrode acceptable. States maybe included. From 1 (a) spontaneous reaction produces Co2+ E° for reaction between Co2+ and Cr2O72– 1.36 –1.82 < 0 V. Hence reaction for further oxidation is not spontaneous so oxidation to Co2+ not Co3+. MeritCorrect answer with partial explanation that includes calculations and comments on the feasibility, and also identifies that Co2+ is formed. Achieved Correct reaction recognised either by the actual reaction OR by inference using the Eo values OR by saying Co2+ formed. Excellence Correct answer with full explanation. May approach from the reverse direction.

  13. Reactions of Acid Chlorides 2. Forming esters from acid chloride – reagents are a primary alcohol Ester From acyl chloride O + HCl R C O R’ From alcohol CH3COCl + CH3OH CH3COOCH3 + HCl ethanoyl chloride + methanol methyl ethanoate + hydrogen chloride

  14. Reactions of Acyl Chlorides 3. acyl chlorides form amides – reagent ammonia and heat Functional group of the amide O R C NH2 CH3COCl + 2NH3 CH3CONH2 + NH4Cl ethanoyl chloride + ammonia ethanamide + ammonium chloride

  15. Reactions of Acyl Chlorides 4. Acyl chlorides forming N - substituted amides – reagent amine O N substituted amide R C NH R’ O O CH3 + NH2 CH3 + HCl CH3 C C NH CH3 Cl Ethanoyl chloride + aminomethane N – methyl ethanamide + hydrochloric acid

  16. Reactions of Acyl Chlorides Acyl chlorides react with water to form acidic solutions O O CH3 CH3 O H C + HCl C O H Cl H ethanoyl chloride + water ethanoic acid + hydrogen chloride

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