Starter - complete the following scheme giving all Formula Ethyl ethanoate Formula? Ethanoyl chloride Formula? Ethanoic acid CH 3 COOH CH 3 COCl CH 3 COOC 2 H 5 Reagents? C 2 H 5 OH + Conc H 2 SO 4 Reagents? H+ CH 3 COOH + C 2 H 5 OH OH- C 2 H 5 NH 2 / ethanol salt + ethanol CH 3 COO - + C 2 H 5 OH ethanamide CH 3 CONH 2 NH 3 / ethanol N-ethylethanamide CH 3 CONH 2 C 2 H 5

Reactions of Amides How can you make ethanamide? 1. ethanoyl chloride and O NH 2 CCH 3 O + NH 4 Cl CCH 3 Cl + NH 3 ethanoyl chloride + ammonia ethanamide + ammonium chloride ammonia

Reactions of amides 1. draw the full structural formula for ethanamide and H 3 O + O NH 2 CCH 3 + H 3 O + O OH CCH 3 + NH 4 + ethanamide + acid organic acid + ammonium ion

Reactions of amides 2. Basic conditions O NH 2 CCH 3 + OH - O O - CCH 3 + NH 3 ethanamide + base conjugate base + ammonia of acid

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 C HO O CH 2 CH 2 CH 2 CH 2 C O OH hexanedioic acid H H N CH 2 CH 2 (CH 2 ) 4 N H H 1,6 diaminohexane diamine dicarboxylic hexanedioic 1,6 diaminohexane

Synthetic polymers continued Polyamides Nylon 6,6 is an example of a ____________ polymer C HO O CH 2 CH 2 CH 2 CH 2 C O OH hexanedioic acid H H N CH 2 CH 2 (CH 2 ) 3 CH 2 N H H 1,6 diaminohexane C HO O CH 2 CH 2 CH 2 CH 2 C O Water removed means a condensation reaction Peptide link condensation Draw the structural formula of nylon 6,6

Task – write the balanced redox reactions for the oxidation of the oxidation of propan-1-ol to propanal using Cr /H+ and give all colour changes. CH 3 CH 2 CH 2 OH Cr CH 3 CH 2 COH + 2H + + 2e- 2Cr H H + + 6e- (X3)33+ 6H + + 6e- 3CH 3 CH 2 CH 2 OH + Cr Cr H H + 3CH 3 CH 2 COH Full balanced redox equation

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

Task – write the balanced redox reactions for the oxidation of the oxidation of propan-2-ol to propanone using Mn0 4 - /H+ and give all colour changes. CH 3 CHOHCH 3 Mn0 4 - CH 3 COCH 3 + 2H + + 2e- Mn H H + + 5e- (X5)55+ 10H e- 5CH 3 CHOHCH 3 + 2Mn Mn 2+ +8H H + 5CH 3 COCH 3 Full balanced redox equation (X2) 2MnO H e- + 8H 2 02Mn 2+

REDOX 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 : Co e – Co E° = – 0.28 V Cr 2 O 7 2– + 14H + + 6e – 2Cr H 2 OE° = 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.

3Co + Cr 2 O 7 2– + 14H+ → 2Cr H 2 O + 3Co 2+ Correct equation a. Achieved E o cell = E(Cr 2 O 7 2– /Cr 3+ ) – E(Co 2+ / Co) = V Correct answer. 1b. Achieved Salt bridge drawn connecting half-cells. One half-cell: Co electrode, Co 2+ solution Other half-cell: Inert electrode eg Pt electrode, K 2 Cr 2 O 7 Achieved - Salt bridge shown OR ONE half cell correctly labelled. Merit - ALL aspects of the cell correctly drawn and labelled. 1c. Pt 1 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. 1c. Pt 2 Evidence

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 Co 2+ or Co 3+. E°(Co 3+ /Co 2+ ) = V From 1 (a) spontaneous reaction produces Co 2+ E° for reaction between Co 2+ and Cr 2 O 7 2– 1.36 –1.82 < 0 V. Hence reaction for further oxidation is not spontaneous so oxidation to Co 2+ not Co 3+. Achieved Co│Co 2+ ║Cr 2 O 7 2–, Cr 3+ │Pt Any inert electrode acceptable. States maybe included. Achieved Correct reaction recognised either by the actual reaction OR by inference using the Eo values OR by saying Co 2+ formed. Merit Correct answer with partial explanation that includes calculations and comments on the feasibility, and also identifies that Co 2+ is formed. Excellence Correct answer with full explanation. May approach from the reverse direction.

Reactions of Acid Chlorides 2. Forming esters from acid chloride – reagents are a primary alcohol O O C R R’ From acyl chloride From alcohol + HCl CH 3 COCl + CH 3 OH CH 3 COOCH 3 + HCl ethanoyl chloride + methanol methyl ethanoate + hydrogen chloride Ester

Reactions of Acyl Chlorides 3. acyl chlorides form amides – reagent ammonia and heat O NH 2 C R Functional group of the amide CH 3 COCl + 2NH 3 CH 3 CONH 2 + NH 4 Cl ethanoyl chloride + ammonia ethanamide + ammonium chloride

4. Acyl chlorides forming N - substituted amides – reagent amine O NH C R N substituted amide Reactions of Acyl Chlorides R’ O Cl C CH 3 + NH 2 CH 3 O C + HCl CH 3 NH Ethanoyl chloride + aminomethane N – methyl ethanamide + hydrochloric acid

Acyl chlorides react with water to form acidic solutions Reactions of Acyl Chlorides O Cl C CH 3 H H O O C HO + HCl ethanoyl chloride + water ethanoic acid + hydrogen chloride