14.2. Alkenes
A subsection of Chemistry, 9701, through 14. Hydrocarbons
Listing 10 of 191 questions
Complete the diagrams to show the energies of the electrons in a carbonatom, a C+ion and a C–ion. increasing energy 1s carbon atom ↑↓ C+ ion ↑↓ C– ion ↑↓ 1s 1s One of the simple molecular allotropes of carbon is buckminsterfullerene, C60. buckminsterfullerene What is the hybridisation of the carbon atoms in C60? C60 reacts with an excess of hydrogen to form a single product, C60Hx. Using your answer to , suggest a suitable value for x. Methylbenzene can undergo different reactions to form the products shown below. CH2Cl Cl CH3 CH3 reaction 1 reaction 2 methylbenzene Give the reagents and conditions for these two reactions. reaction 1 reaction 2 Name the mechanism of reaction 1. Draw the structure of the product obtained if reaction 1 is carried out using an excess of chlorine.
9701_m16_qp_42
THEORY
2016
Paper 4, Variant 2
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The compound Advantame is a sweetener that tastes approximately 25 000 times sweeter than sucrose. RO HO OH CH3 H N O O O O Advantame N H Advantame is optically active. On the diagram of Advantame, circle all the chiral carbon atoms. The decomposition of Advantame produces three molecules, J, K and L. The RO–group in Advantame is unreactive. HO OH OH H N O O + O OH H2N J K + L RO Suggest possible reagents and conditions for this decomposition. Name the type of reaction occurring. Draw the structure of L in the box above. Aqueous bromine was added dropwise to a solution of J until the bromine was in excess. State what you would observe. J has the molecular formula C14H19O6N. Use this formula to write an equation for the reaction of excess aqueous sodiumhydroxide with one mole of J. State what you would observe when an excess of aqueous bromine is added to a solution of K. K can be polymerised. Draw the structure of the polymer showing two repeat units. The linkage between the monomer units should be fully displayed. Use the Data Booklet to help you answer this question. The carbon-13 NMR spectrum of K was recorded. O K OH H2N State how many different carbon environments are present in K. The chemical shifts, δ, due to two of the carbon atoms x and y present in K are given in the table. carbon atom δ / ppm x y On the structure of K, circle and label two carbon atoms which could correspond to x and y.
9701_m17_qp_42
THEORY
2017
Paper 4, Variant 2
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Compounds J and K are found in plant oils. OH O C C J CHO H3C CH3 H C C K H CH3 COOH Complete Table4.1 to state what you would observe when J reacts with the reagents listed. Table 4.1 reagent observation with J 2,4-dinitrophenylhydrazine (2,4-DNPH) Tollens’ reagent sodium metal  J has two optical isomers. Draw the three-dimensional structures of the two optical isomers of J.  K is used to make the addition polymer Perspex®. A synthesis of Perspex® is shown in Fig.4.2. H C C K H CH3 COOH H C C Perspex® M H CH3 COOCH3 reactant L reaction 1 reaction 2 Identify L. State the conditions required for reaction1. L = conditions =  Draw one repeat unit of the addition polymer Perspex®.  Use information from Table4.2 to suggest how the infrared spectra of M and Perspex® would differ. Explain your answer. Table 4.2 bond functional group containing the bond characteristic infrared absorption range (in wavenumbers) / cm–1 C–O hydroxy, ester 1040–1300 C=C aromatic compound, alkene 1500–1680 C=O amide carbonyl, carboxyl ester 1640–1690 1670–1740 1710–1750 C≡N nitrile 2200–2250 C–H alkane 2850–3100 N–H amine, amide 3300–3500 O–H carboxyl hydroxy 2500–3000 3200–3650 K can be made from propanone in the three-step synthesis shown in Fig.4.3. H C C K H CH3 COOH C O propanone H3C CH3 C C H3C CH3 C H3C CH3 COOH OH OH N step 1 step 2 step 3 Complete Table4.3 to identify the reagentused and the type of reaction in each step. Table 4.3 step reagenttype of reaction Al 2O3  
9701_m22_qp_22
THEORY
2022
Paper 2, Variant 2
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