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Nomen: ____________________________________________________ Dies:____________________________Unit 10b (Topic 10 and 20) Organic Chemistry Nightly Homework

Lesson 0 – Pre-Introduction to Organic Chemistry Catenation Saturated Unsaturated Electrophile

Nucleophile Aliphatics Arenes

Homolytic fission

Heterolytic fission

Lessons 1 to 3 Intro To Orgo IUPAC Homologous series Structural isomer Skeletal formula

Alkane, alkene, alkyne, alcohol, ether

Aldehyde, ketone, carboxylic acid


Halogenoalkane, amine, ester, nitrile, arene.

Hydroxyl, carboxyl

Cyclic and non-cyclic Primary, secondary, tertiary

1. State the condensed structural formulas, together with their IUPAC names, for all the structural isomers of C6H14.

2. Models showing the structural formulas of two compounds A and B, both with a similar molar mass (74 and 72 g mol-1 respectively), are shown below:

(a) Identify the functional groups contained in compounds A and B.(b) State the IUPAC names for compounds A and B.(c) Deduce which of the two compounds, A or B, will have the higher boiling point and which will be more soluble in water. Explain your deduction.

3. (a) State the IUPAC names of the following three alcohols:

(b) Classify these three alcohols in terms of primary, secondary or tertiary.

4. Identify the functional groups present in:(a) Tyrosine and (b) Aspirin


Lessons 4 and 5 Stereoisomerism conformational isomer configurational isomer E/Z CIP (Cahn–Ingold–Prelog)

priority chiral

enantiomer diastereomer racemic mixture racemate polarimeter

1. Deduce how many different four-membered ring isomers exist for dichlorocyclobutane and name each isomer.

2. Explain why 1,2-dichloroethane cannot exhibit cis/trans isomerism whereas 1,2-dichloroethene can. Explain whether or not 1,2-dichloroethane can show conformational isomerism.

3. Explain why cis-butenedioic acid reacts to form a cyclic compound with the loss of water when heated whereas trans-butenedioic acid does not.

4. 2-amino acids have the general formula H2NCH(R)COOH. Explain why glycine, H2NCH2COOH, the simplest 2-amino acid, does not exist in two enantiomeric forms whereas all the other 2-amino acids do.

5. Three of the first four compounds shown in Section 37 of the IB Chemistry data booklet are the ‘over the counter’ pain killers, aspirin, paracetamol (acetaminophen) and ibuprofen. Identify which, if any, can show optical isomerism. The fourth is penicillin – can this also be optically active?

6. The straight chain structural formula of glucose is given in Section 34 of the IBChemistry data booklet. Explain why glucose can have diastereomers.

7. Name the following compounds, A and B, using E/Z nomenclature.


Lesson 6 Alkanes, Alkenes, and Addition Polymerization free radical initiation step propagation

step termination

step

addition reaction

hydrogenation hydration halogenation symmetrical

alkene

addition polymerization

poly(ethene) poly(chloroethe

ne) poly(propene)

1. State the balanced equations for the complete combustion (under standard conditions) of 2-methylbutane, C5H12 (boiling point: 28 oC), 3-methylpentane, C6H14, and octane, C8H18.

2. If the ratio of air to gasoline (petrol) entering a car engine is reduced then the amount of air pollution caused by oxides of nitrogen emitted in the exhaust gas is lowered. However, the concentration of two other air pollutants is increased. Identify these two pollutants and explain how they arise.

3. The first step in the reaction between methane and chlorine in the presence of ultraviolet light is the homolytic fission of the chlorine to chlorine single bond, Cl-Cl(g), in gaseous chlorine.

(a) Explain the meaning of the term homolytic fission.(b) Explain why homolytic fission occurs with the Cl-Cl bond in chlorine and not the C-H bond in methane.(c) State the name of the product formed when the Cl-Cl bond is broken homolytically and state its electron configuration.(d) Explain why only a few homolytic fission reactions involving chlorine need to be successful in order to bring about the complete reaction between chlorine and methane to form chloromethane and hydrogen chloride.

4. The reaction between bromine and ethane occurs in the presence of ultraviolet light.

(a) Explain why ultraviolet light is necessary for the reaction to proceed.(b) Describe, using equations, the stepwise mechanism of the reaction between one mol of bromine and one mol of ethane to form one mol of bromoethane and one mol of hydrogen bromide.(c) Describe how you could make pure 1,2-dibromoethane from bromine and ethane.

1. State the equation and name the organic product when propene reacts with:(a) hydrogen using a nickel catalyst at 180oC.(b) chlorine gas in the absence of water.

2. Describe how you could distinguish practically between hexane and hex-3-ene by using a simple chemical reaction. Describe what you would observe in each case and state any relevant equations and name any products formed.


3. Ethanol is increasingly being produced commercially by the fermentation of crops in order to use as a biofuel in place of/in addition to gasoline (petrol). This is ecologically friendly in terms of greenhouse gas emissions but it is using up vast areas of land which could be used for food production. Ethanol can also be made industrially by the hydration of ethene. State the equation for the hydration of ethene.

4. (a) State the equation and name the organic product when but-2-ene reacts with hydrogen iodide.(b) Unlike the reaction with but-2-ene, the reaction of but-1-ene with hydrogen iodide is not on the IB Core. This is because in theory it can give two different organic products although in practice only one of them is formed. Deduce the identity of the two possible products.

5. (a) Draw the structure of the repeating unit of poly(chlorethene).(b) Deduce the structure of the repeating unit of poly(tetrafluoroethene).(c) Poly(tetrafluoroethene) is also known as ‘Teflon’ or ‘non-stick’ and it is used to make artificial joints for humans as well as coat frying pans. Suggest a reason why it is so unreactive.

Lesson 7 Alcohols primary secondary tertiary

reflux distillation esterification

1. State the equations for the complete combustion of:(a) ethanol(b) propan-2-ol

2. Propan-2-ol and propan-1-ol can both be oxidized by a warm acidified solution of potassium dichromate(VI).

(a) Describe what would be observed in both cases.(b) State the IUPAC name of the product from the oxidation of propan-2-ol and state the simplified equation (use [O] to represent the oxygen from the acidified potassium dichromate(VI) solution).(c) The half-equation for the reduction of the acidified dichromate(VI) ion is:Cr2O7

2–(aq) + 14H+(aq) + 6e– → 2Cr3+(aq) + 7H2O(l)Deduce the full equation for the oxidation of propan-2-ol using acidified Cr2O72– ions.(d) State the IUPAC name of the two organic products that can be formed when propan-1-ol is oxidized by warm acidified potassium dichromate(VI) solution.(e) Explain why propan-1-ol can form two different organic products whereas propan-2-ol only forms one organic product when oxidized by acidified potassium dichromate(VI) solution.


(f) Describe how you could separate the two organic products formed from the oxidation of propan-1-ol.

Lesson 8 and 9 Nucleophilic Substitution 'curly' arrow heterolytic fission SN1 (unimolecular nucleophilic

substitution) SN2 (bimolecular nucleophilic

substitution)

carbocation transition state protic solvent aprotic solvent

1. Explain the following statements:(a) hydroxide ions are better nucleophiles than water molecules.(b) the hydrolysis of iodoethane is faster than the hydrolysis of bromoethane.(c) the hydrolysis of 2-bromo-2-methylpropane is faster than the hydrolysis of 1-bromobutane.(d) fluoroethane does not react with dilute sodium hydroxide solution to form ethanol.

2. Explain the mechanism for the reaction of ammonia with bromoethane. (Use curly arrows to show the movement of pairs of electrons.)

3. (a) Explain why the substitution of primary halogenoalkanes by hydroxide ions could also be classed as a Lewis acid-base reaction.(b) Explain whether the reaction of tertiary halogenoalkanes with hydroxide ions could also be classed as a Lewis acid-base reaction.

4. Suggest how tetramethylammonium bromide, (CH3)4N+Br–, could be made from bromomethane.

Lesson 10 Electrophilic Addition Markovnikov carbocation electrophile electrophilic addition

induced dipole asymmetric interhalogen

1. Bromine is a non-polar molecule.(a) Explain how it is able to act as an electrophile when it adds to ethene.(b) Name the product when bromine is added to ethene in the absence of water.(c) Explain why the major product obtained is 2-bromethanol if bromine water is added to ethene.

2. Describe the mechanism for the addition of hydrogen bromide to prop-1-ene.Your answer should include the use of curly arrows to show the movement of electron pairs and give the structure and IUPAC name for the major product formed.


3. Deduce the structure and IUPAC name of the major product formed when iodine chloride, I-Cl, is added to but-1-ene.

4. Draw the structure of the intermediate carbocation formed when 2-methylbut-2-ene reacts with hydrogen chloride and state whether the carbocation is primary, secondary or tertiary.

Lesson 11 Electrophilic Substitution arene nitration

nitronium ion electrophilic substitution

1. Describe and explain the structure of benzene by considering the hybridization that occurs on each carbon atom.

2. Benzene reacts with a mixture of concentrated nitric and sulfuric acid at a temperature not exceeding 50 oC.

(a) State the equation for the reaction that occurs.(b) Explain the role of the concentrated sulfuric acid.(c) Identify the electrophile in this reaction.(d) Explain why substitution rather than addition occurs.(e) Show the mechanism for this reaction using curly arrows.(f) Suggest a reason why the temperature is not raised above 50 oC.

3. Benzene can also undergo an electrophilic substitution reaction with chlorine in the presence of aluminum chloride, AlCl3, to form chlorobenzene.

(a) Deduce the equation for this reaction.(b) Based on your knowledge of electrophiles suggest the identity of the

electrophile in this reaction and deduce the role of aluminum chloride in its formation.

Lesson 11 – Reduction sodium borohydride, NaBH4

lithium aluminium hydride, LiAlH4

phenylamine, C6H5NH2

1. Two different organic products can be obtained when 2-methylbutanoic acid is reduced using lithium aluminum hydride, LiAlH4.Identify the two organic products by giving their systematic (IUPAC) name and write equations for the reactions.

2. There are four different alcohols that are structural isomers with the molecular formula C4H10O.

(a) Identify the four different structural alcohols by giving their systematic (IUPAC) name.


(b)Three of the four different alcohols can be prepared by reducing an aldehyde or a ketone using sodium borohydride, NaBH4. Identify which three together with the aldehyde or ketone that can be used to prepare it.(c) Explain why the fourth alcohol cannot be prepared by reducing an aldehyde or ketone.

3. Phenylamine can be prepared by firstly refluxing nitrobenzene with a mixture of tin metal and concentrated hydrochloric acid then reacting the organic product formed from this first step with sodium hydroxide solution.

(a) Identify the role played by the tin metal in this reaction.(b) State the name of the intermediate organic compound formed in this reaction and state the half-equation for its formation.(c) State the equation for the reaction of this intermediate organic product with sodium hydroxide to form phenylamine.

Lesson 12 – Synthesis

1. Starting with 2-methylpropane deduce a synthetic pathway to make 2-methylpropanoic acid.

CH3CH(CH3)CH3 → CH3CH(CH3)COOHFor each step specify the reagents and any necessary conditions and write an equation for each step.

2. Design a synthetic route to make butanone starting with but-1-ene.CH3CH2CHCH2 → CH3CH2COCH3


Knowing that the first step involves the addition of hydrogen bromide to but-1-ene state the name of the mechanism for the first two steps.

3. You are provided with ethanal and any inorganic reagents and laboratory equipment you require but no other organic compounds. Design a method to synthesise ethylethanoate from ethanal.

CH3CHO → CH3COOC2H5

For each step specify the reagents and any necessary conditions.

4. Show how phenylamine can be synthesised from benzene.

5. Propyl ethanoate is used as a solvent and has the characteristic smell of pears.Design a synthetic route to make propyl ethanoate starting from 1-chloropropan and chloroethane as the only organic compounds available.

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