9701_m23_qp_22 - revisedeck

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The Pauling electronegativity values of elements can be used to predict the chemical properties of compounds. Use the information in Table 1.1 to answer the following questions. Table 1.1 element H Li C O S Pauling electronegativity value 2.1 1.0 2.5 3.5 2.6 first ionisation energy / kJ mol–1 second ionisation energy / kJ mol–1 — Define electronegativity. O and S are in Group 16. Explain the difference in the Pauling electronegativity values of O and S. LiH is an ionic compound. Draw a dot‑and‑cross diagram of LiH. Include all electrons. Suggest the shape of a molecule of H2S. Write an equation that represents the first ionisation energy of H. Explain why there is no information given in Table 1.1 for the second ionisation energy of H. Give the full electronic configuration of S2+. CO2 and SO2 are acidic gases. Write an equation for the reaction of SO2 with H2O. Write an equation for the reaction of SO2 with NaOH. Construct an equation for the reaction of CO2 with Mg(OH)2. Complete Table 1.2 by placing a tick (✓) to show which of the compounds have molecules with an overall dipole moment. Table 1.2 compound O=C=O O=S=O S=C=S S=C=O overall dipole moment At 150 °C and 103 kPa, all of the compounds listed in Table 1.2 are gases. Under these conditions, 0.284 g of one of the compounds occupies a volume of 127 cm3. Use this information to calculate the Mr of the compound. Hence, identify the compound from those given in Table 1.2. Show your working. Mr = identity of compound =

3. Chemical bonding → 3.1. Electronegativity and bonding

2. Atoms, molecules and stoichiometry → 2.3. Formulas

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The Group 2 elements Mg to Ba are all silvery‑white reactive metals. Draw a labelled diagram to show the bonding and structure of the Group 2 metals at room temperature. Explain why Mg has a higher electrical conductivity than Na. Write an equation for the reaction of magnesium with cold water. Identify a single reagent that can be used to distinguish separate samples of dilute Mg(NO3)2and dilute Ba(NO3)2. Explain your answer. reagent explanation Describe what is observed when SrI2reacts with concentrated sulfuric acid. Compound X, an anhydrous Group 2 bromide, is dissolved in water and titrated against aqueous silver nitrate. A solution containing 0.250 g of X requires 33.65 cm3 of 0.0500 mol dm–3 AgNO3for complete reaction. Identify X. Show your working. X =

10. Group 2 → 10.1. Similarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds

11. Group 17 → 11.3. Some reactions of the halide ions

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Alkenes undergo an addition reaction with a 1:1 mixture of CO and H2 to form aldehydes. shows the reaction of propene with a 1:1 mixture of CO and H2. propene A B H2 CO CHO CHO and Define addition reaction. Aldehydes A and B are structural isomers. State the type of structural isomerism shown by A and B. Name A. The complete reaction of propene with a 1:1 mixture of CO and H2 produces A and B only. The product mixture contains 96% A and 4% B. Calculate the mass of A produced in this reaction when 5.00 × 103 kg of propene is used. mass of A = kg A and B show reactions typical of aliphatic aldehydes. A undergoes a nucleophilic addition reaction with a mixture of HCN and KCN, forming compound C. Complete the diagram to show the mechanism for this reaction. Include charges, dipoles, lone pairs of electrons and curly arrows, as appropriate. Draw the structure of the organic intermediate. A C O OH CN C H C H C3H7 C3H7 Table 3.1 shows information about three experiments involving B. Complete Table 3.1. Table 3.1 experiment reagents observation with B solution turns from orange to green a silver mirror forms on the sides of the reaction vessel Br2 B, C4H8O, is oxidised by acidified potassium manganate(. Complete the equation for this reaction. Use [O] to represent one atom of oxygen from the oxidising agent. C4H8O + C is a chiral molecule. Circle any chiral centres in the structure of C shown in . C OH C N III C H H C H H C H H C H H When propene reacts with CO and an excess of H2, an alkane and a mixture of alcohols are formed instead. The alcohols are isomers of each other. Suggest the molecular formulae of the alkane and the alcohols that are formed under these conditions. molecular formula of alkane molecular formula of alcohols The reaction of ethene, C2H4, with a 1:1 mixture of CO and H2 is shown in equation 1. equation 1 C2H4+ CO+ H2CH3CH2CHOAt atmospheric pressure a cobalt‑based catalyst is used in this reaction. State and explain the effect of using a catalyst on this reaction. Explain why the yield of CH3CH2CHOincreases when the overall pressure of the reaction mixture is increased. Use the information in Table 3.2 to calculate the enthalpy change, ΔHr, of the reaction in equation 1. equation 1 C2H4+ CO+ H2CH3CH2CHOTable 3.2 compound enthalpy change of formation, ΔHf / kJ mol–1 C2H4+52 CO–111 CH3CH2CHO–187 ΔHr = kJ mol–1 The reaction mixture is cooled to collect CH3CH2CHO as a liquid. Identify all types of van der Waals’ forces that are present between molecules of CH3CH2CHO.

17. Carbonyl compounds → 17.1. Aldehydes and ketones

14. Hydrocarbons → 14.2. Alkenes

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shows some reactions of compound D, 2‑bromobutane. D E Br H CH2NH2 G CN F OH reaction 2 AgNO3in ethanol reaction 4 KCN dissolved in ethanol reaction 1 addition polymer reaction 3 alkaline I2reaction 5 LiAlH4 yellow precipitate + an organic ion State the reagent and conditions used to form E in reaction 1. Draw the structure of one repeat unit of the addition polymer that forms from E. E also forms when F is heated strongly in the presence of an Al 2O3 catalyst. Write an equation for this reaction. Predict what is observed in reaction 2. Identify the yellow precipitate and the organic ion formed in reaction 3. yellow precipitate organic ion State the type of reaction that occurs in reaction 4. Reaction 5 is similar to the reaction of LiAl H4 with carboxylic acids to form alcohols. Suggest the role of LiAl H4 in reaction 5. shows the infrared spectrum of one of the compounds D, E, F, G or H. wavenumber / cm–1 transmittance / % Use information from Table 4.1 (on page 14) to identify which of the compounds D, E, F, G or H produces the infrared spectrum in . Explain your answer. Table 4.1 bond functional groups 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 2850–2950 N–H amine, amide 3300–3500 O–H carboxyl hydroxy 2500–3000 3200–3600 In the mass spectrum of D, the relative abundance of the molecular ion peak is 3.4. Predict the relative abundance of the M+2 peak for D. Explain your answer.

15. Halogen compounds → 15.1. Halogenoalkanes

14. Hydrocarbons → 14.2. Alkenes

14. Hydrocarbons → 14.1. Alkanes

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