14. Hydrocarbons
A section of Chemistry, 9701
Listing 10 of 313 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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Glycerol, CH2(OH)CH(OH)CH2OH, is widely used in the food industry and in pharmaceuticals. A series of reactions starting from glycerol is shown. CH2OH CH2OH C H OH COOH COOH C NC OH C Q P HOOC HOOC O reaction 1 reaction 2 NaCN and HCN Suggest the reagentand conditions for reaction1. Name the reaction mechanism for reaction2. Give the observation you would make when 2,4-dinitrophenylhydrazine is added to P. Q does not show optical isomerism. Explain why. When Q is heated with excess aqueous ethanoicacid in the presence of a catalytic amount of sulfuricacid, two reactions take place to form compound R. COOH COOH HOOC C OCOCH3 R Identify the two types of reaction that occur.  Glycerol can be used as a starting material in the manufacture of nitroglycerine, C3H5N3O9. Nitroglycerine decomposes rapidly on heating to form a mixture of gases. 4C3H5N3O912CO2+ 10H2O+ 6N2+ O2A sample of nitroglycerine decomposes, releasing 1.06 dm3 of O2at 850 K and 1.00×105 Pa. Calculate the mass of nitroglycerine that decomposes.  mass of nitroglycerine = g Calculate the total volume of gas released by this decomposition at 850 K and 1.00×105 Pa.  total volume of gas = dm3 Fats are compounds made from glycerol and unsaturated carboxylic acids. 4-pentenoic acid is an example of an unsaturated carboxylic acid. (CH2)2COOH H 4-pentenoic acid H H Give the molecular formula of 4-pentenoic acid. Draw the repeat unit of the addition polymer that can be formed from 4-pentenoic acid.  Unsaturated acids are often brominated before being added to soft drinks. Complete the mechanism for the addition of Br2 to 4-pentenoic acid. ● ● Include the structures of the intermediate and the product of the reaction. ● ● Include all charges, partial charges, lone pairs and curly arrows. In the mechanism, R has been used to represent (CH2)2COOH. H R Br Br H H  A reaction of another unsaturated carboxylic acid, T, is shown. Br C6H13 T HOOC Br C6H13 U HOOC T is one of a pair of geometrical (cis-trans) isomers. Draw the other geometrical isomer of T and explain why the molecules exhibit this form of isomerism.  Identify the reagent used to convert T to U. The C–Br bond has an absorption between 500 cm–1 and 600 cm–1 in an infrared spectrum. The infrared spectra for both T and U have absorptions between 2850 cm–1 and 2950 cm–1. These correspond to C–H bonds. Identify: ● ● two other absorptions that would be seen in the infrared spectra of both T and U ● ● one other absorption that would only be seen in the infrared spectrum of T. For each absorption, give the range of the absorption and the bonds that correspond to these absorptions. absorption 1 present in both spectra absorption 2 present in both spectra absorption only present in spectrum of T  
9701_m20_qp_22
THEORY
2020
Paper 2, Variant 2
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Carboplatin and satraplatin are used as anticancer drugs instead of cisplatin. carboplatin satraplatin Pt NH3 N H2 O O O O Cl Cl O O O NH3 NH3 O Pt Describe the action of cisplatin as an anticancer drug. Suggest the geometry of the platinum centre in the carboplatin complex. Suggest why carboplatin does not show cis-trans isomerism. Satraplatin is a neutral complex, containing the ligands CH3CO2 –, C6H11NH2, Cl – and NH3. Deduce the oxidation state of platinum in satraplatin. CompoundM is made from 1,3-dimethylbenzene in a two-step synthesis. 1,3-dimethylbenzene C8H6O4 Cl Cl O M L O step 1 step 2 Draw the structure of L.  Suggest reactants and conditions for each step of this synthesis. step 1 step 2  Write an equation for step2. A student investigates a possible synthesis of M directly from benzene using COCl 2 in the presence of an Al Cl 3 catalyst. Benzene initially reacts with COCl 2 as shown. reaction 1 COCl 2 + Al Cl 3 → Al Cl 4 – + Cl C O reaction 2 C6H6 + Cl C O → C6H5COCl + H+ Reaction 2 is the electrophilic substitution of Cl C O for H+ in benzene. Suggest a mechanism for reaction2.   + + +
9701_m21_qp_42
THEORY
2021
Paper 4, Variant 2
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Questions Discovered
313