A Level Official Exam Material
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Unit 5: Transition Metals and
Organic Nitrogen Chemistry
Topic 20: Organic Synthesis
For A Level students only
For A Level students only
Q1. Steam distillation is a technique used during some organic preparations to separate the product from the reaction mixture
What benefit is gained from the use of steam distillation compared to other methods of distillation? (1)
A a pure distillate is produced
B high distillation temperatures are required
C it works well for molecules miscible with water
D it avoids the decomposition of the organic molecule when it distils
(Total for question = 1 mark)
Q2. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
The melting temperature is determined for impure crystals of an organic compound.
When compared with a data book value for the pure compound, the measured melting temperature
A will be the same as the true value
B will be higher than the true value
C will be lower than the true value
D could be higher or lower than the true value
(Total for question = 1 mark)
Q3. Answers the question with a cross in the boxes you think are correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
This question is about a Grignard reagent, 2-methylpropylmagnesium bromide.
This Grignard reagent can be prepared by refluxing 1-bromo-2-methylpropane with magnesium in a flask containing a dry solvent and anti-bumping granules.
(a) Which solvent is used in this preparation? (1)
A ethanol
B ether
C pentane
D propanone
(b) Why are anti-bumping granules added to the flask? (1)
A to lower the boiling temperature of the solvent
B to prevent the solvent evaporating
C because the solvent is highly flammable
D to ensure the solvent boils smoothly
(c) The structure of 2-methylpropylmagnesium bromide is shown.
Which statement best describes the circled carbon atom? (1)
A positive and electrophilic
B positive and nucleophilic
C negative and electrophilic
D negative and nucleophilic
(d) Which compound reacts with 2-methylpropylmagnesium bromide to form 4-ethyl-2-methylheptan-4- ol?
Q4. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
In the high resolution proton NMR spectrum of propan-2-ol, CH3CHOHCH3 there are
A one singlet, one doublet and a heptet
B one singlet, two doublets and a heptet
C two singlets and two triplets
D three singlets and a quartet
(Total for question = 1 mark)
Q5. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
The structure of a hydrocarbon is shown.
A four
B five
C seven
D eight
(Total for question = 1 mark)
Q6. For each question, select one answer from A to D and put a cross in the box .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
The infrared spectrum of a compound X is shown.
Q7. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
The electronic configuration of the atoms of an element is 1s22s22p63s23p63d54s1 .
What is the maximum oxidation number shown in compounds of this element? A +1 B +5 C +6 D +7
(Total for question = 1 mark)
Q8. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
When a sample of a hydrocarbon is burned completely in oxygen, 2.64 g of carbon dioxide and 0.81 g of water are formed. Which of these could be the molecular formula of the hydrocarbon?
A C2H3
B C4H3
C C4H6
D C12H9
(Total for question = 1 mark)
Q9. For each question, select one answer from A to D and put a cross in the box .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross . Methylbenzene reacts with a mixture of concentrated nitric acid and concentrated sulfuric acid to form 2,4,6-trinitromethylbenzene.
(a) What is the number of peaks in the 13C NMR spectrum of methylbenzene? (1)
A seven
B six
C five
D four
(b) What type of reaction takes place? (1)
A nucleophilic addition
B nucleophilic substitution
C electrophilic addition
D electrophilic substitution
(c) Which expression shows the mass in grams of 2,4,6-trinitromethylbenzene formed from 10 g of methylbenzene if the yield of the reaction is 85 %?
[Mr values: methylbenzene = 92 2,4,6-trinitromethylbenzene = 227] (1)
A (10 × 85 × 227) ÷ (92 × 100)
B (10 × 100 × 227) ÷ (92 × 85)
C (10 × 100 × 227) ÷ (92 × 115)
D (10 × 115 × 227) ÷ (92 × 100)
(Total for question = 3 marks)
Q10. Answer the question with a cross in the box you think is correct .
If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .
What is the minimum volume of oxygen gas, measured at room temperature and pressure, required for the complete combustion of 9.2 g of C3H8O3 (Mr = 92)?
[Molar volume of gas at room temperature and pressure = 24.0 dm3 mol−1 ]
A 4.8 dm3
B 8.4 dm3
C 12.0 dm3
D 16.8 dm3
(Total for question = 1 mark)
Q11. This question is about the investigation of an organic compound X. X is a liquid at room temperature and pressure, which turns damp red litmus paper blue.
(a) (i) Name the functional group present in X. (1) .............................................................................................................................................
(ii) When 0.493 g of X was vaporised, 157 cm3 of dry air was displaced, measured at 15°C and 103 000 Pa.
Calculate the molar mass of X, using the ideal gas equation.
You must show your working. (4)
(b) X reacted vigorously with ethanoyl chloride forming steamy fumes and a white solid Y.
(i) Identify the steamy fumes, by name or formula. (1) ............................................................................................................................................. .............................................................................................................................................
(ii) Suggest the functional group present in Y. (1) .............................................................................................................................................
(iii) Analysis of Y showed that its composition by mass was 62.6 % carbon; 11.3 % hydrogen; 12.2 % nitrogen; 13.9 % oxygen.
Determine the empirical formula of Y.
You must show your working. (3)
*(c) A simplified high resolution proton NMR spectrum of Y is shown.
The relative peak areas are given near each peak.
Deduce the structure of Y, using the NMR spectrum and the other information in the question. (6)
(d) Draw the structure of compound X. (1)
(Total for question = 17 marks)
Q12. This question is about aromatic amines and amino acids.
(a) A synthesis of phenylamine is shown.
(i) Benzene is converted into nitrobenzene in Step 1 using a mixture of concentrated nitric acid and concentrated sulfuric acid. The electrophile is .
A student drew a mechanism for the reaction.
Describe the three changes needed to correct this student's mechanism. (3)
Change 1 ............................................................................................................................................. ............................................................................................................................................. .............................................................................................................................................
Change 2 ............................................................................................................................................. ............................................................................................................................................. .............................................................................................................................................
Change 3 ............................................................................................................................................. ............................................................................................................................................. .............................................................................................................................................
(ii) Give the reagents for Step 2. (1)
............................................................................................................................................. .............................................................................................................................................
(b) Phenylamine is a base.
(i) Explain why phenylamine is a weaker base than ammonia. (3)
............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. .............................................................................................................................................
(ii) State what is seen when a few drops of an aqueous solution of phenylamine are added to an aqueous solution containing Cu2+ ions. (1)
............................................................................................................................................. .............................................................................................................................................
(c) Azo violet is used as a dye and an indicator. A synthesis of azo violet from 1-amino-4-nitrobenzene is shown.
(i) Give the reagents and condition for Step 1. (2) ............................................................................................................................................. .............................................................................................................................................
(ii) Deduce the structure of the organic compound needed to produce azo violet in Step 2. (1)
(iii) Give a reason why azo violet exists as geometric isomers. (1) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. .............................................................................................................................................
(d) Phenylalanine is an amino acid that exists as optical isomers.
The structure of one of the optical isomers is shown.
Complete the diagram to show the other optical isomer of phenylalanine. (1)
Q12. Ketones are useful starting compounds in organic synthesis.
This question is about butanone.
(a) The mass spectrum of butanone has significant peaks at m / z = 43 and at m / z = 57.
(i) Give the structures of the species responsible for these two peaks. (2)
(ii) Give the structure of one other species that you would expect to produce a peak at a different m / z value in the mass spectrum of butanone. (1)
(b) Devise a reaction scheme to prepare propan-1-ol from butanone, using no more than four steps.
Identify the reagents and essential conditions for each step and give the name or structure of each of the intermediate compounds. (4)
(c) Devise a reaction scheme to prepare 2-methylbut-2-ene from butanone, using no more than four steps.
Identify the reagents and essential conditions for each step and give the name or structure of each of the intermediate compounds. (5)
(Total for question = 12 marks)
Q13. The ester ethyl 2-methylbutanoate is found in wild berries such as bilberries.
Devise a synthesis to convert but-2-ene into ethyl 2-methylbutanoate in four steps.
Include the reagents and essential conditions for each step and the name or structure of each of the intermediate compounds. Details of practical procedures are not required.
(Total for question = 6 marks)
Q14. A compound Q contains the elements carbon, hydrogen and oxygen only.
(a) Combustion analysis of 4.91 g of Q produces 14.6 g of carbon dioxide and 3.58 g of water.
Show that the molecular formula of Q is C10H12O .
You must show all your working. [Mr of Q = 148] (4)
(b) The high resolution proton NMR spectrum of Q is shown.
Deduce the structure of Q.
Justify your answer by considering the relative peak areas, the chemical shifts and the splitting patterns.
You will find it helpful to refer to page 8 of the Data Booklet.
The peak at 3.6 ppm is due to a proton environment on a carbon bonded to the benzene ring.
The peak is not where it might be expected from the general values in the Data Booklet. (7)
(Total for question = 11 marks)
Q15. A series of reactions with iron and iron complexes was carried out.
Reaction 1 A sample of iron was heated with hydrochloric acid and a pale green hydrated salt A with molar mass 198.8 g mol–1 was crystallised from the solution.
Reaction 2 Salt A was dissolved in water forming a pale green solution containing complex ion B.
On addition of excess aqueous potassium cyanide, KCN, the solution turned yellow due to the formation of complex ion C.
Reaction 3 Chlorine gas was bubbled through the solution containing complex ion C forming a red solution of complex ion D. Salt E, the potassium salt of complex ion D, was then crystallised from the solution.
(a) Deduce the formula of the hydrated salt A. You must show your working. (2) .............................................................................................................................................
(b) Give the formula of complex ion B. (1)
.............................................................................................................................................
(c) Complex ion C has six cyanide ligands.
Draw the structure of C, clearly showing its three-dimensional shape. (1)
(d) The percentage composition by mass of salt E is K = 35.6% Fe = 17.0% C = 21.9% N = 25.5%
Calculate the empirical formula of salt E. (3)
(e) Write the ionic equation for the reaction of complex ion C with chlorine to form complex ion D. (2)
(f) Complete the table, using as appropriate, to identify the type of each reaction. (2)
If you need the markscheme, including the examiners' reports for each question, and more exam and teaching materials on this topic, contact me through the contact page