Organic chemistry - Assignment Example

of Centre: of Westminster College Learner achievement (please circle) NB: All learner achievement is provisional until confirmed at the AVAAwards Board Level Achieved: L2 L3 Final Grade Achieved (Level 3 units only) P M D Resubmission? Y N Title of Access to HE Diploma: Science (e.g. Science) Unit title(s): The Chemistry of Organic Compounds Unit code(s): RD4/3/LN/017 Learner: Tutor/Assessor: Jack Khan/Dave Pearson Description of Assignment: The assignment will be split into two tasks. In the first task the learner must complete a series of questions related to the assessment criteria as detailed below the brief. Question 1 AC 1.1, Question 2 AC 1.2, Question 3 a) & b) AC 2.1, Question 3 c) AC 2.2, Question 3 d) AC 2.3, Question 4 a) AC 3.1 & 3.3, Question 4 b) AC 3.2, Question 4 c) AC 3.4, Question 4 d) AC 3.5, Question 4 e) AC 3.6, Question 5 AC 4.1, Question 6 AC 4.2, Question 7 AC 4.5, Question 8 AC 4.6. In the second task, the learner must complete a series of practical tests and produce a report identifying an unknown organic compound. You will also have to interpret spectra relating to the unknown compound. This will cover some criteria which have not been covered in the first task as well as some that have. Question A i) AC 4.2, Question A ii) AC 4.3, Question A bi) AC 4.4, Question c) AC 2.1, 2.3 The course work can be completed with the aid of external resources i.e. notes from class, text books, internet etc. However it must be written in your own words and or referenced where appropriate. Date set: Date for draft submission (if applicable): Date for final submission: Extension date (if agreed): Signed by Tutor/Assessor to agree extension: Date submitted: Learner declaration: I certify that the work submitted for this assignment is my own. I have clearly referenced any sources used in the work. I understand that false declaration is a form of malpractice. Learner comments: (please use this space to comment on any aspect of the assignment when handing in your work) Signature: Date: TO THE LEARNER: Please attach this assignment brief to any written work you are handing in for assessment, or submit the brief as instructed. YOUR WORK CANNOT BE ASSESSED UNLESS YOU HAVE SIGNED AND SUBMITTED THIS FORM Level 2/3 (please circle) Unit title: The Chemistry of Organic Compounds This assignment addresses the following Assessment Criteria from the unit (or a copy of the unit may be attached, if all AC are covered): AC no Level Three 1.1 Explain the formation of hybrid electron orbitals in carbon and their relation to the formation of sigma and pi bonds 1.2 Illustrate the formation of free radicals, from covalent bond homolysis, and the formation of carbonium ions from covalent bond heterolysis 2.1 Use experimental analytical data to calculate the empirical and molecular formula of an unknown organic compound 2.2 Derive possible structural formulae for an unknown organic compound from its molecular formulae 2.3 Identify the probable structural formula/formulae of an unknown organic compound from experimental data relating to its chemical, physical and spectroscopic properties 3.1 Classify organic compounds from their structural formulae 3.2 Explain the characteristic properties of an homologous series of organic compounds 3.3 Identify common functional groups in organic structures (eg: C=C, C=C, halogeno, hydroxyl, ester, carbonyl, carboxyl, nitrile, nitro, amine and amide,) 3.4 Use the IUPAC systematic names to name simple aliphatic, aromatic and alicyclic compounds and their isomers 3.5 Write and name the molecular formulae and displayed structural formulae for a range of different types of organic compounds, and their structural isomers and stereoisomers 3.6 Examine the structural formulae of unfamiliar organic compounds and draw conclusions about their classification, nomenclature, bonding and 3-dimensional shape 4.1 Explain how the physical properties of organic compounds relate to their structure 4.2 Analyse and interpret data relating to the physical properties of organic compounds 4.3 Explain, with balanced equations, characteristic reactions of some of the organic functional groups 4.4 Explain, with balanced equations, the mechanism of a named organic reaction (eg: electrophilic addition or substitution, nucleophilic addition or substitution, esterification, saponification) 4.5 Examine the displayed structural formulae of unfamiliar organic compounds and draw conclusions relating to their possible physical and chemical properties 4.6 Compare and contrast the physical and chemical properties of isomers eg: structural isomers, cis and trans geometrical isomers, and enantiomers) Level 3 units only: Learners achieve a Pass if they meet all Level 3 Assessment Criteria for a unit. You will achieve a Merit or Distinction by meeting the following Grade Descriptors. Your tutor will give you feedback for all three grades. Grade Descriptor Merit (Choose one or more relevant grade components) Distinction (Choose one or more relevant grade components) GD2: Application of knowledge The student, students work or performance makes use of relevant facts, theories & models with either breadth or depth that goes beyond the minimum required to Pass and/or very good levels of analysis & synthesis. The student, students work or performance makes use of relevant facts, theories & models with both breadth and depth and/or excellent levels of analysis & synthesis. Grade Descriptor Merit (Choose one or more relevant grade components) Distinction (Choose one or more relevant grade components) GD3: Application of skills The student, students work or performance generally selects appropriate methods and/or applies appropriate (selected or given) techniques with very good levels of consistency & accuracy The student, students work or performance consistently selects appropriate methods and/or applies appropriate (selected or given) techniques with excellent levels of consistency & accuracy Grade Descriptor Merit (Choose one or more relevant grade components) Distinction (Choose one or more relevant grade components) GD7: Quality The student, students work or performance is structured in a way that is generally logical and fluent puts forward arguments or ideas which are generally unambiguous but which are in a minor way limited or incomplete. The student, students work or performance is structured in a way that is consistently logical and fluent puts forward arguments or ideas which are consistently unambiguous and cogent. Grade Guidance: Learners must carefully read the guidance below which is linked to the components above MERIT: (e.g. To achieve a Merit your work will show…..) For a merit your work will show that you can generally draw structural formula, identify and name organic compounds with minor mistakes, that you can describe typical reactions of some of the functional groups, with explanations where again some minor mistakes and incomplete answers will be acceptable. You should be able to draw mechanisms or organic reactions generally using the correct notation. You will be able to calculate formulas and interpret spectra giving more than a basic explanation of the logic you used to come to your conclusions. Your report will show a logical and generally complete set of explanations when interpreting tests and spectra, where more than one spectra is correctly interpreted. DISTINCTION: (e.g. To achieve a Distinction your work will show…..) For a distinction your work will show that you can consistently draw structural formula, identify and name organic compounds with almost no mistakes that you can describe typical reactions of some of the functional groups, with explanations with no mistakes and complete answers consistently. You should be able to draw mechanisms or organic reactions consistently using the correct notation. You will be able to calculate formulas and interpret spectra giving more than a basic explanation of the logic you used to come to your conclusions. Your report will show a logical and consistently complete set of explanations when interpreting tests and spectra, where all spectra is correctly interpreted. Part A: Feedback on credit level AC no Credit achieved (L2/L3) Location of evidence Tutor/Assessor comments on assessment criteria (you could also indicate on the work itself where each AC is met) 1.1 1.2 2.1 2.2 2.3 3.1 3.2 3.3 3.4 3.5 3.6 4.1 4.2 4.3 4.4 4.5 4.6 Level achieved Tutor/Assessor’s signature: Date: Resubmission (if applicable) If any of the assessment criteria for this assignment have not been met at Level 3, a resubmission may be permitted. Resubmission must follow the QAA guidelines and be permitted only once. Requirements for resubmission/new Task set: Date Set: Date due: Date Submitted: Feedback on resubmission: Level achieved after resubmission: Tutor/Assessor’s signature: Date: Part B: Feedback on grading (Applicable only if all assessment criteria achieved at Level 3) Grade Descriptor Tutor/Assessor comments against grade descriptors Grade indicator (P/M/D) Please enter the final grade on page 1 based on this grade profile e.g. PPM=P GD2: Application of knowledge GD3: Application of skills GD7: Quality Tutor/Assessor’s reason for final grade decision (if applicable): Task 1 AC 1.1 1. a) Using the box and arrow diagrams for electron configuration show why sigma and pi bonds form in carbon compounds. Note you must explain the formation of both sigma and pi bonds. Sigma bonds for between the hybrid orbitals of two adjacent atoms while the pi bonds form between the unhybridized orbitals of two adjacent atoms. Carbon compounds have both hybrid and unhybridized orbitals therefore they can form both sigma and pi bonds. The sigma bonds are formed by the compounds with single bonds while pi bonds are found in the double and triple bonds (Rawn & Ouellette, 2014).. AC 1.2 2. a) I. Using the appropriate arrow notation show the mechanism for the formation of a Halogenoalkane via free radical substitution of the following reactants clearly explaining how the reaction is initiated and where homolytic fission is taking place. Br2 (g) + CH3CH2CH3(g) The reaction starts with the initiation step where the bromine molecule is split into two bromine atoms by the hemolytic bond fission by impact absorption of the ultraviolet photon. From this stage is the chain propagation step where another new free radical is produced to continue the reaction. The last part of the reaction is the chain termination stage where the highly reactive free radicals are removed and the unpaired electrons form a new bond (Solomons, Fryhle & Snyder, 2014). II. Using the appropriate arrow notation explain why there is more than one product formed. b) Using the appropriate arrow notation show the mechanism for the formation of a Halogenoalkane/s via electrophilic addition of the following reactants clearly explaining how the reaction is initiated and where heterolytic fission is taking place. You also need to explain why you get two different products. HCl(aq) + AC 2.1 3. a) After a combustion experiment an unknown organic compound was found to contain 68.2% Carbon, 13.6% Hydrogen, and 18.2% Oxygen. Calculate the empirical formula. Carbon: hydrogen: oxygen 68.3%: 13.6%: 18.2% 68.2/12: 13.6/1: 18.2/16 5.683: 13.6: 1.1375 5.683/1.1375: 13.6/1.1375: 1 5: 12: 1 Therefore the empirical formula formula is C5H12O b) The molecular mass has been identified as 88.15g. Calculate the molecular formula. The molecular mass of the compound is 12*5 + 12 + 16= 88 g Molecular mass = 88.15 g 88.15/88= 1.0017= 1.00 Hence its molecular formula = C5H12O AC 2.2 c) Using the molecular formula you have calculated, identify the possible structural formulas of this unknown compound. CH2(OH)CH2CH2CH2CH3 CH3CH(OH)CH2CH2CH3 CH3CH2CH(OH)CH2CH3 AC 2.3 d) The unknown compound was shown to have a boiling point higher than water and a melting point of around 80°c. Also, it is slightly soluble in water. When the compound was reacted with acidified potassium dichromate it turned from orange to green. Identify with reasoning which structural formula you think the unknown compound might be (from the isomers you identified in part III). The compound is most likely pentan 1- ol. This compound has a higher boiling point than water because the van der Waals force in alcohols increases with increasing molecular weight. The melting point of pentan-1-ol is790 C. AC 3.1 & 3.3 4. a) Identify the functional group for the following organic compounds and write the generic formula for it. I. The functional group is alkyl halide Generic formula CH3C (CH3Cl) CH3 II. The functional group is carboxylic acids The generic formula is CH3CH2CH2COOH III. The functional group is an aldehyde The generic formula is C (CH3)2CHO IV. The functional group is amide The generic formula is NH2CH2COOH V. The functional group is aromatic compounds AC 3.2 b) Describe how the boiling points and solubility of alcohols change as the carbon chain gets longer. Give reasons for these properties. The solubility of alcohols decreases as the carbon chain increases. This is because as the carbon chain increases the long chain complexes the formation of hydrogen bends between the alcohol and water molecules hence decreasing solubility (Wade, 2013). The boiling point of alcohols increases with increase in the carbon chain. This is because the strength of the van der Waals forces and the intermolecular interaction forces increase with increasing molecular weight of the alcohols (Wade, 2013).. AC 3.4 c) Write the IUPAC names of the organic above. I 2 chloro, 2 methyl propane II Pentanoic acid III 2 methyl propanal IV Ethan amide V 1 methyl benzene. AC 3.5 d) For the following molecular formulae draw the possible displayed structural formula, identify the types of isomers these structures represent. You should have at least one example of each type of 5 main types of isomers. I. C5H10O II. C6H12O III. C6H10O AC 3.6 e) From the following condensed structural formulae: Draw their displayed structural formulae. Identify if they could have any stereoisomers and explain why. Name the compound using the IUPAC system being clear to state what homologous series the compound belongs to. State what type of intramolecular and intermolecular bonds the molecule can make and explain your reasons. I. CH3CHOHCH2CH2CH3 II. CBrFCClCH2CH3 III. CH3CH2CH2COOH IV. CHClCHBr CH3CHOHCH2CH2CH3 -pentan-2-ol Straight chain alcohols This compound is not likely to have stereoisomers since it’s a straight chain alcohol. All its atoms are aligned in same plane in space. The intramolecular forces of attraction are covalent bonds and the intermolecular forces of attraction are the hydrogen bonds because of the bonds between oxygen atom and hydrogen atom. CBrFCClCH2CH3 - 1 bromo, 1fruoro, 2 chloro but-1-ene Halogenoalkene This compound does not show stereoisomerism since all the atoms bonded to the carbon atom are on the same plane and cannot change orientation to assume different positions. The intramolecular forces of attraction are covalent bonds while the intermolecular forces are the van der Waals forces. CH3CH2CH2COOH – butanoic acid Straight chain alkanoic acid This is a straight chain carboxylic acid and cannot have stereoisomerism. This molecule has covalent bonds as intramolecular forces of attraction and hydrogen bonds as intermolecular forces of attraction. CHClCHBr – 1bromo, 2 chloro ethene Halogenoalkene This compound is the one that shows stereoisomerism since the Cl and Br atoms can chance their positions and obtain either the cis or the trans isomers. This molecule is bonded by covalent bonds and weak van der Waals forces. AC 4.1 (part 4.5) 5. For the molecules in 4e, describe their physical properties and explain how these properties relate to their structure. A was the alcohol since it had a higher boiling point and showed partial solubility in water. Solution B was the alkene since it dissolved fully in water and had a lower boiling point than the alcohol due to weak van der Waals force of attraction while the alcohol has hydrogen bonds. AC 4.2 6. A technician accidentally mislabelled some organic liquids one of which was a long chain alkane and another was an alcohol of similar molecular weight. She poured a sample in water of each and found unknown A, showed partial solubility whereas unknown B did not show any. When she tested their boiling point she found unknown A had a boiling point of 137°C and Unknown B had a boiling point of 68°C. Given the above information, identify which is the alkane and which is the alcohol, giving an explanation of the answers. A was the alcohol since it had a higher boiling point and showed partial solubility in water. Solution B was the alkene since it dissolved fully in water and had a lower boiling point than the alcohol due to weak van der Waals force of attraction while the alcohol has hydrogen bonds AC 4.5 7. For the following organic compounds, identify what type of reactions they may undergo as well as any physical properties they may have. Give reasons for your conclusions. a) It is a carboxylic acid therefore it reacts with salts to form carboxylate salts. In addition, it also reacts with alcohols to produce esters. Physical properties The compounds are polar substances and therefore they dissolve in polar solvents and are less soluble in non-polar solvents. They have a higher boiling point than water due to their ability to form dimers. b) This is a carboxylic acid with a thiol group, it forms alcohols upon reaction with hydrogen. It also forms thioesters and thioethers when it react with esters and ethers. Physical Properties They are weak acids and dissociates in water partially to give hydrogen ions. The derivative shown in b is a volatile one and has a strong odor. a) It is a carboxylic acid with thiol and amine group. it forms alcohols upon reaction with hydrogen. It also forms thioesters and thioethers when it react with esters and ethers. Physical Properties As a result it is a weaker acid as compared to other acids such as HCl. They have a density of between 0.63-0.84 making it less dense than water. AC 4.6 8. Compare and contrast the physical and chemical properties of the following isomers. a) The D-glucose and L-glucose are made up of the same atoms. The difference between the two structures is displayed through the fisher model. The oxygen and hydrogen atoms in the D-glucose point to the right while in the L-glucose these atoms point to the left. Apart from the difference in the alignment these two isomers have similar chemical properties. b) Pentanol is a colorless liquid with an unpleasant smell. It has a boiling and melting point of 1370 C and -780 C respectively. It is partially soluble in water but dissolves at high temperatures 3 methyl butanol has boiling and melting points of 117.70C and -89.80c respectively. It’s slightly more soluble in water than Pentanol and very soluble in non-polar solvents. Task 2 (Please see the attached file) You must carry out preliminary tests to identify the functional group of an unknown organic compound that was found in the scene of a crime, and then interpret data and spectra provided to you about the unknown compound. Make sure you write the aim, method, results and conclusions. In your conclusion you need to: (AC 4.2) a) Interpret the physical data for your unknown organic compound and explain what this tells you about it. From the experimental data the compound was found to get oxidized by potassium dichromate to form a green precipitate. The compound was oxidized to form a carboxylic acid. It was also found to be partially soluble in water and had a pH of about 7. These properties proved that the compound was an alcohol (Bruice, 2014). (AC 4.3) b) I. Write the balanced equations for the chemical reactions taking place in the tests and give a brief explanation of the reaction including the name of the type of reaction happening. In the experiment there was only one reaction for the oxidation of the compound by potassium dichromate. The balanced chemical equation is as shown below: CH3CH2CH2OH + 2 Cr2O72- + 16 OH → 3 CH3CH2COOH +4 Cr3+ +12H2O. (AC 4.4) II. For the Bromine water test, (in addition to the above) show the mechanism including any intermediary products using standard arrow notation. There was no reaction. (AC 2.1, 2.3) c) The following data was found from a combustion experiment for the unknown compound you tested. 60.0% carbon, 13.4% hydrogen, and 26.6% oxygen I. Determine the empirical formula Carbon: hydrogen: oxygen 60%: 13.4%: 26.6% 60/12: 13.4: 26.6/16 5: 13.4: 1.6625 5/1.6625: 13.4/1.6625: 1 3: 8: 1 From these calculations the empirical formula is C3H8O. II. From the mass spectrum below determine the molecular formula giving an explanation of your logic. From the mass spectrum the molecular mass of the compound is 60 The empirical mass = 60. Therefore the molecular formula = C3H8O. III. Draw out the possible isomers from the molecular formula 2 isomers IV. Using the mass spectrum below identify which isomer the compound is; giving reasons for your conclusion. From the mass spectrum and the H-NMR spectrum provided the most likely isomer is the propan1-ol. This is identified from the many peaks observed by the H-NMR spectra which signify the four types of hydrogen in the propan-1-ol. d) You have received another set of data from another sample. This time an IR spectra and Proton NMR Spectra has been produced. Explain with reasoning if you think that this is the same substance. The IR spectrum shows peaks at about 2800cm-1, 1500cm-1 and 900cm-1. These peaks do not represent the IR peaks produced by an alcohol since an alcohol produces a strong O-H peak at around 3600cm-1, a C-O band which is strong and broad at between’ 1150-1050 cm-1. The HNMR spectrum produced showed a compound with five sets of hydrogen atoms. However our compound had four sets of hydrogen atoms. Therefore from these differences in the spectra it is clear that this compound is not an isomer if C3H8O. H-NMR spectra of sample References BRUICE, P. Y. (2014). Organic chemistry. Boston : Pearson RAWN, J. D., & OUELLETTE, R. J. (2014). Organic chemistry. San Diego, CA : Elsevier. SOLOMONS, T. W. G., FRYHLE, C. B., & SNYDER, S. A. (2014). Organic chemistry. Hoboken, NJ : Wiley WADE, L. G. (2013). Organic chemistry. Boston, Pearson. Read More

Your report will show a logical and generally complete set of explanations when interpreting tests and spectra, where more than one spectra is correctly interpreted. DISTINCTION: (e.g. To achieve a Distinction your work will show…..) For a distinction your work will show that you can consistently draw structural formula, identify and name organic compounds with almost no mistakes that you can describe typical reactions of some of the functional groups, with explanations with no mistakes and complete answers consistently.

You should be able to draw mechanisms or organic reactions consistently using the correct notation. You will be able to calculate formulas and interpret spectra giving more than a basic explanation of the logic you used to come to your conclusions. Your report will show a logical and consistently complete set of explanations when interpreting tests and spectra, where all spectra is correctly interpreted. Part A: Feedback on credit level AC no Credit achieved (L2/L3) Location of evidence Tutor/Assessor comments on assessment criteria (you could also indicate on the work itself where each AC is met) 1.1 1.2 2.1 2.2 2.3 3.1 3.2 3.3 3.4 3.5 3.6 4.1 4.2 4.3 4.4 4.5 4.

6 Level achieved Tutor/Assessor’s signature: Date: Resubmission (if applicable) If any of the assessment criteria for this assignment have not been met at Level 3, a resubmission may be permitted. Resubmission must follow the QAA guidelines and be permitted only once. Requirements for resubmission/new Task set: Date Set: Date due: Date Submitted: Feedback on resubmission: Level achieved after resubmission: Tutor/Assessor’s signature: Date: Part B: Feedback on grading (Applicable only if all assessment criteria achieved at Level 3) Grade Descriptor Tutor/Assessor comments against grade descriptors Grade indicator (P/M/D) Please enter the final grade on page 1 based on this grade profile e.g. PPM=P GD2: Application of knowledge GD3: Application of skills GD7: Quality Tutor/Assessor’s reason for final grade decision (if applicable): Task 1 AC 1.1 1. a) Using the box and arrow diagrams for electron configuration show why sigma and pi bonds form in carbon compounds.

Note you must explain the formation of both sigma and pi bonds. Sigma bonds for between the hybrid orbitals of two adjacent atoms while the pi bonds form between the unhybridized orbitals of two adjacent atoms. Carbon compounds have both hybrid and unhybridized orbitals therefore they can form both sigma and pi bonds. The sigma bonds are formed by the compounds with single bonds while pi bonds are found in the double and triple bonds (Rawn & Ouellette, 2014).. AC 1.2 2. a) I. Using the appropriate arrow notation show the mechanism for the formation of a Halogenoalkane via free radical substitution of the following reactants clearly explaining how the reaction is initiated and where homolytic fission is taking place. Br2 (g) + CH3CH2CH3(g) The reaction starts with the initiation step where the bromine molecule is split into two bromine atoms by the hemolytic bond fission by impact absorption of the ultraviolet photon.

From this stage is the chain propagation step where another new free radical is produced to continue the reaction. The last part of the reaction is the chain termination stage where the highly reactive free radicals are removed and the unpaired electrons form a new bond (Solomons, Fryhle & Snyder, 2014). II. Using the appropriate arrow notation explain why there is more than one product formed. b) Using the appropriate arrow notation show the mechanism for the formation of a Halogenoalkane/s via electrophilic addition of the following reactants clearly explaining how the reaction is initiated and where heterolytic fission is taking place.

You also need to explain why you get two different products. HCl(aq) + AC 2.1 3. a) After a combustion experiment an unknown organic compound was found to contain 68.2% Carbon, 13.6% Hydrogen, and 18.2% Oxygen. Calculate the empirical formula.

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