Level 3 Chemistry – Industrial Chemical Reactions and Industrial Applications of Organic Chemistry

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Level 3 Chemistry – Industrial Chemical Reactions and Industrial Applications of Organic Chemistry
Part 1 – Industrial Chemical Reactions
Task 1 – Equilibrium Processes
(1) What is an equilibrium reaction?
(2) What is Le Chateliér’s Principle?
(3) Consider the following reaction and answer the questions that follow:
N2O4 (g) 2 NO2 (g) ?H = 56.9 kJ
(a) Write out an expression for the equilibrium constant (Kc) for this reaction.
(b) How would increasing the temperature of the equilibrium mixture affect the position of the equilibrium for this equilibrium process? Give a reason for your answer.
(c) How would an increase in the concentration of N2O4 affect the position of the equilibrium for this equilibrium process? Give a reason for your answer.
(d) How would increasing the pressure of the system affect the position of the equilibrium for this equilibrium process? Give a reason for your answer.
(4a) Explain the importance of enthalpy change, equilibrium, and the rate of reaction to the Haber process and the Contact Process. Include an explanation of how the two processes are optimised for achieving the greatest yield of product and to achieve maximum profits. This should go into some detail about why it is important for the company to operate these processes under non-standard conditions.
(b) (1) The Haber process is used to produce ammonia from nitrogen and hydrogen and is an important process for the production of fertilisers.
N2(g) + 3H2(g) 2NH3 ?H = -92 kJ/mol
Analyse how the operating conditions (such as temperature and pressure) for this process are optimised to obtain maximum yield economically.
Task 2 – Redox reactions in industry and corrosion
(1) Define what corrosion is and give some examples?
(2) What does the reduction potential tell you about how reactive a metal is?
(3) What happens to the oxidation state of metals when they react to form compounds? Why does this tend to happen?
(4) Using reduction potentials place the following metals in order from least likely to corrode to most likely to corrode. Explain how you arrived at your conclusion.
Copper (Cu), Iron (Fe), Titanium (Ti), Zinc (Zn), Calcium (Ca)
(Please note you need to use the reduction potential for the metal and not the metal ion).
(5) List at least four different types of corrosion control methods that can be used to protect metals from corrosion.
(6) Redox reactions are used extensively in industrial processes. Choose two of the applications listed below and explain how knowledge of reduction potentials is important in the development of processes and in plant design (maximum 100 words).
• Metal extraction methods used for different metals.
• The risk of corrosion in reaction vessels containing reagents that could react with the metal itself, such as bromine.
• The risk of corrosion on an oil platform in the ocean.
The risk of corrosion in reaction vessels and pipes in processes that occur in an acid environment.

Task 3 – pH and buffers
(!) What is the difference between a strong and weak acid?
(2) Give an example of a strong acid and show in an equation what happens when a strong acid is added to water.
(3) Give an example of a weak acid and show in an equation what happens when a weak acid is added to water.
(4) Write out an expression for the acid dissociation constant (Ka) for ethanoic acid (CH3COOH).
(5) What does the size of the acid dissociation constant tell you about the acid?
(6) Put the acids in the table below in order of strength. Explain how you have come to your answer.
Acid Ka at 25oC
Hydrofluoric acid 5.6 x 10-4
Nitrc acid 40
Chloroethanoic acid 1.3 x 10-3
Dichloroethanoic acid 5.0 x 10-2

(7) Explain why is it important to use buffer solutions in the following industrial settings?
a. Dyeing industry
b. Fermentation and food industry
c. Pharmaceutical industry
d. Cosmetics industry
e. Electroplating industry

Add further information to meet all grading criteria’s if needed and state which criteria it is for.

Task 1 a. Explain chemical equilibrium in terms of the concentrations of reactants and products
Task 1 b. Examine how physical chemistry concepts may be applied to the control of industrial processes.
Task 2 c. Explain corrosion tendency in terms of standard reduction potential
Task 2 d. Examine how physical chemistry concepts may be applied to the control of industrial processes.
Task 3 e. Explain strength of acids and bases in terms of the acid dissociation constant
Task 3 f. Examine how physical chemistry concepts may be applied to the control of industrial proccesses.
Grading Criteria Checklist (for part1)

Part 2 – Industrial Uses of Organic Chemistry
Task 1 – Structure of Hydrocarbons
(1) Name the following molecules;
a) b)

c) d)

(2) For each of the following molecules;
(2-methyl butane), (Propane), (2-metylbut-2-ene), (Ethene), (2,3-dimethyl butane), (Benzene), (2,4-dimethyl pent-2-ene)
Give the following;
• The full structural formula,
• Shortened structural formula,
• Skeletal formula
• Wedge/dashed line diagram

Task 2 – Physical and Chemical Properties of Hydrocarbons
(1) Produce a graph in which you plot the number of carbons against the boiling point for the following alkanes. Then answer the questions that follow.
Table1. The boiling points of some alkanes
Alkane Boiling point
(K) Number of carbon atoms
ethane 184.5
propane 231
butane 272.6
pentane 309.2
hexane 341
heptane 371.5
octane 398.8

(a) Using the graph you have drawn describe how the boiling point of an alkane changes as the chain length increases.
(b) Explain why the boiling point increases as the chain length increases.

(2) Compare the boiling points of alkanes and alkenes of similar length and answer the questions that follow.
Table 2. A comparison of the boiling points of alkanes and alkenes
Alkane Boiling point
(K) Alkene Boiling point
(K)
propane 231 propene 226
pentane 309.2 pentene 309
hexane 341 hexene 336
octane 398.8 octene 395

(a) How different are the boiling points of alkenes and alkanes of similar length?
(b) On average, how does the boiling point of an alkene compare to that of an alkane?
(c) In both cases, what intermolecular forces are found between the molecules?
(3) Describe and explain how the structure of benzene was discovered. How does the double bond system in benzene differ from that found in other alkenes?
(4a) Are hydrocarbons soluble in water?
(b) Using what you know about solubility and intermolecular forces, explain the solubility of hydrocarbons.
(5) Hydrocarbons are used for fuel. Write out the reaction showing the combustion of hydrocarbons such as alkanes.
(6a) List all the typical reactions of alkanes.
(b) List all the typical reactions of alkenes.
(c) List all the typical reactions of benzene.
(7) Provide mechanisms/diagrams, including a commentary explaining each step for the following reactions:
(a) A free radical substitution reaction of methane with chlorine;
(b) An electrophilic addition reaction of bromine to ethene;
(c) The nitration of benzene.

Task 3 – Reactions of carbonyl compounds
(1) Predict the products of the following reactions.

(2) Plan the multi-step synthesis of two of the following molecules:
(a) Triiodomethane from but-2-one
(b) An azo dye from benzene
(c) Conversion of ethanol into propanal
(d) 2-hydroxypentanenitrile from bromobutane
(e) N-(4-hydroxyphenyl)ethanamide from phenol
(3) Choose three of the reactions below and describe clearly and in detail how the reaction is carried out.
(a) Synthesis of azo dyes
(b) Preparing soap
(c) Oxidation reactions of aldehydes
(d) Making of an ester
(e) Reaction of methylbenzene with bromine
(4) For the three reactions that you have chosen, identify the functional groups present and the typical reactions of those groups.

Task 4 – Commercial importance of isomerism
(1) Answer the following questions about structural isomerism:
(a) Define the term structural isomerism.
(b) Name and define the three different types of structural isomerism.
(c) Find images of the following molecules and identify what type of isomers they are and write down their empirical formulae:
(i) Pentane; 2-methylbutane; and 2,2-dimethylpropane;
(ii) Butanol, Butan-2-ol, 2-methylpropan-2-ol;
(iii) Propanal, propanone, and prop-2-ene-1-ol

(2) Answer the following questions on the properties of structural isomers:
(a) The boiling point of pentane is 34?C, for 2-methylbutane it is 28?C and for 2,2-dimethylpropane it is 9.5?C. Explain why the boiling points of these three isomers would be different.

(b) Answer these two questions concerning butanol, butan-2-ol, and 2-methyl-propan-2-ol.
(i) The boiling point of butanol is 118?C, for butan-2-ol it is 100?C and for 2-methyl-propan-2-ol it is 83 ?C. Explain why the boiling points of these three isomers would be different.
(ii) For each of these alcohols predict and explain the products of a reaction with potassium dichromate.

(c) Answer these two questions concerning propanal, propanone, and prop-2-ene-1-ol.
(i) The boiling point of propanal is 49?C, for propanone it is 56?C and for prop-2-ene-1-ol is 97?C. Explain why the boiling point for prop-2-ene-1-ol is greater than for propanal and propanone.
(ii) Predict and explain the reaction (if there is one) of propanal, propanone, and prop-2-ene-1-ol with each of the following reagents:
• 2,4-dinitrophenylhydrazine (2,4-DNP)
• Tollen’s reagent
• Potassium dichromate
• Bromine water
• Ethanoic acid
• Sodium borohydride (NaBH4)

(3) Stereoisomerism
(a) Define the term stereoisomerism.
(b) What is a geometric isomer? Draw the two geometric isomers of but-2-ene.
(c) What is an optical isomer? Draw the two optical isomers of butan-2-ol.

(4) The boiling point of trans-but-2-ene is 0.9?C and that of cis-but-2-ene is 3.7?C. Why is the boiling point of the cis isomer greater than that of the trans isomer?
(5) For each of the molecules below circle the chiral centre or centres of that molecule (copy and paste image(s) onto answer document):

(a) Alanine (b) glyceraldehyde

(c) glucose (d) Serine

(e) Ibuprofen (f) Malate

(6) Oleic acid and Elaidic acid are the cis and trans isomers of the fatty acid with the structural formula, C9H17C9H17O2.
(a) Find and paste an image of these two isomers.
(b) Oleic acid has a melting point of 13.4?C and Elaidic acid has a melting point of 45?C. Explain the consequences of these melting points on the state of the fatty acid and room temperature. Explain why these two molecules have different melting points.
(c) In some countries such as the US, the inclusion of trans-fats in processed foods by the food industry has been actively discouraged and even banned. Research why this is, and explain what it is about the physical properties of trans-fats that make them dangerous (word count – 100 words).

(7) The diagram below shows the molecular structure of thalidomide.
(a) Identify the chiral centre of the molecule.
(b) Explain using this example why it is important to be aware of isomerism.

(8) Select a well-documented example of an optical isomer and discuss in detail its different chemical and/or therapeutic properties. Examples you could choose from are ibuprofen or thalidomide (Word count – 250 words maximum).

Add further information to meet all grading criteria’s if needed and state which criteria it is for.

Task 1 a. Name hydrocarbons correctly in relation to their structure
Task 1 b. Construct a range of representations of hydrocarbons, illustrating the bonding and spatial arrangement of hydrocarbon molecules.
Task 2 c. Describe the physical and chemical properties of industrially important hydrocarbons
Task 2 d. Provide mechanisms for reactions of hydrocarbons.
Task 3 e. Predict the products of a range of commercially important reactions, involving carbonyl compound
Task 3 f. Plan multi-step syntheses of organic molecules
Task 3 g. Carry out reactions involving organic compounds safely
Task 3 h. Describe the reactions carried out practically in terms of the functional groups involve
Task 4 i. Examine the commercial importance of different types of isomers
Task 4 j. discuss the chemical/ therapeutic importance of isomerism
Grading Criteria Checklist (for part2)
Task 1 a. Name hydrocarbons correctly in relation to their structure
Task 1 b. Construct a range of representations of hydrocarbons, illustrating the bonding and spatial arrangement of hydrocarbon molecules.
Task 2 c. Describe the physical and chemical properties of industrially important hydrocarbons
Task 2 d. Provide mechanisms for reactions of hydrocarbons.
Task 3 e. Predict the products of a range of commercially important reactions, involving carbonyl compound
Task 3 f. Plan multi-step syntheses of organic molecules
Task 3 g. Carry out reactions involving organic compounds safely
Task 3 h. Describe the reactions carried out practically in terms of the functional groups involve
Task 4 i. Examine the commercial importance of different types of isomers
Task 4 j. discuss the chemical/ therapeutic importance of isomerism

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