9701_s24_qp_22
A paper of Chemistry, 9701
Questions:
5
Year:
2024
Paper:
2
Variant:
2
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1
Complete Table 1.1 using relevant information from the Periodic Table. Table 1.1 nucleon number proton number number of electrons Mg2+ Al 3+ State and explain the difference in the ionic radius of Al 3+ compared to Mg2+. Draw a labelled diagram to show the structure and bonding in sodium. shows the variation in melting point of some Period 3 elements in their standard states at room temperature and pressure. Na Mg Al Si element melting point / K P S Cl Explain why Si has a high melting point. Complete to show the variation in the melting points of the elements P, S and Cl. Two Period 3 elements react with an excess of oxygen at room pressure. Complete Table 1.2. Table 1.2 Period 3 element state of oxide at room temperature and pressure approximate pH of solution made when oxide is added to water Na S The solutions made in column 3 of Table 1.2 are mixed together. Name the type of reaction that occurs. Write an equation to describe the reaction between P4O10 and an excess of water. Aluminium hydroxide is amphoteric. Explain what is meant by amphoteric. Write an equation to describe the reaction that occurs when aluminium hydroxide, Al (OH)3, reacts with NaOH. , ,
9. The Periodic Table: chemical periodicity  →  9.2. Periodicity of chemical properties of the elements in Period 3
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Separate samples of Na2CO3 and NaHCO3 react with HCl to produce the same products, as shown in Table 2.1. Table 2.1 reaction equation ∆H / kJ mol–1 Na2CO3 + 2HCl 2NaCl + H2O + CO2 ∆H1 NaHCO3 + HCl NaCl + H2O + CO2 ∆H2 = +27.2 Complete the reaction pathway diagram in for reaction 2. Label the diagram to show the enthalpy change, ∆H2, and the activation energy, EA. NaHCO3 + HCl energy / kJ mol–1 progress of reaction The value for ∆H1 is determined by experiment using the following method. • 50.0 cm3 of 2.00 mol dm–3 HCl is added to a polystyrene cup. • The initial temperature of the acid is recorded as 19.6 °C. • 0.0400 mol of Na2CO3 is added and the mixture is stirred. • All the solid Na2CO3 disappears and a colourless solution is produced. The maximum temperature recorded during the reaction is 26.2 °C. Describe one other observation that shows the reaction is complete. Calculate the value of ∆H1 in kJ mol–1. Assume the specific heat capacity of the reaction mixture is the same as for water and no heat is lost to the surroundings. Show your working. ∆H1 = kJ mol–1 Thermal decomposition occurs when NaHCO3 is heated. reaction 3 2NaHCO3 Na2CO3 + H2O + CO2 Calculate the enthalpy change for reaction 3, ∆Hr , using the data in Table 2.1 and the value of ∆H1 calculated in . (If you were unable to calculate a value for ∆H1 in , assume the enthalpy change is –38.4 kJ mol–1. This is not the correct value.) ∆Hr = kJ mol–1 Z is a salt that contains a Period 4 element from Group 2. When Z is heated brown gas forms. Identify the formula of Z and use it to write an equation for the reaction. , ,
5. Chemical energetics  →  5.1. Enthalpy change, \(\Delta H\)
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Describe what is meant by dynamic equilibrium. Reaction 4 describes the reversible reaction between yellow Fe3+and colourless SCN–to produce red FeSCN2+. reaction 4 Fe3++ SCN–FeSCN2+yellow colourless red An equilibrium mixture contains Fe3+, SCN–and FeSCN2+. A few colourless crystals of soluble KSCNare added. The mixture is then left until it reaches equilibrium again. The temperature of both equilibrium mixtures is the same. Deduce the changes that occur, if any, in the equilibrium mixture after KSCNis added compared to the original equilibrium mixture. • change in appearance • change in relative concentration of Fe3+• change in value of the equilibrium constant, Kc The expression for the equilibrium constant, Kc, for reaction 4 is shown. Kc = [FeSCN2+] [Fe3+] × [SCN–] 5.00 × 10–5 mol of Fe3+and 5.00 × 10–5 mol of SCN–are added together and allowed to reach equilibrium. The total volume of the mixture is 25.0 cm3. At equilibrium the concentration of FeSCN2+is 4.23 × 10–4 mol dm–3. Calculate the equilibrium constant, Kc, for reaction 4. Include the units in your answer. Kc = units , , Determine the full electronic configuration of Fe3+. SCN–is colourless. Complete the dot-and-cross diagram in to show the arrangement of outer electrons in an SCN– ion. S C N – ,  ,
7. Equilibria  →  7.1. Chemical equilibria: reversible reactions, dynamic equilibrium
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CH3(CH2)5CHBrCH3 exists as a pair of stereoisomers. Draw the three-dimensional structures of the two stereoisomers of CH3(CH2)5CHBrCH3. R can be used to represent CH3(CH2)5. A sample of CH3(CH2)5CHBrCH3 reacts with NaOH to make CH3(CH2)5CH(OH)CH3 in an SN1 mechanism. Complete to show the mechanism for the reaction of CH3(CH2)5CHBrCH3 and NaOH. Include charges, dipoles, lone pairs of electrons and curly arrows, as appropriate. CH3(CH2)5 Br C H CH3 CH3(CH2)5 OH C H CH3 Separate samples of CH3(CH2)5CHBrCH3, CH3(CH2)5CH(OH)CH3 and CH3(CH2)5CHCH2 are tested with different reagents. Complete Table 4.1. If no reaction occurs, write × in the relevant box. Table 4.1 reagent added observation with CH3(CH2)5CHBrCH3 observation with CH3(CH2)5CH(OH)CH3 observation with CH3(CH2)5CHCH2 Br2in the dark PCl 5AgNO3CH3(CH2)5CHBrCH3 is heated with D to produce three different molecules, E, F and G. F E G Name the type of reaction. Identify D and the conditions used. Both σ and π bonds are present in a molecule of E as a result of different types of hybridisation in the carbon atoms. Complete Table 4.2 to show the number of carbon atoms with each type of hybridisation in a molecule of E. Table 4.2 number of carbon atoms sp hybridised sp2 hybridised sp3 hybridised E Describe the essential feature of an unbranched hydrocarbon that causes its molecules to show stereoisomerism. Explain how this feature leads to stereoisomerism. , ,
13. An introduction to AS Level organic chemistry  →  13.3. Shapes of organic molecules; σ and π bonds
14. Hydrocarbons  →  14.2. Alkenes
3. Chemical bonding  →  3.4. Covalent bonding and coordinate (dative covalent) bonding
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Compound W has molecular formula C4H10O. It contains only one functional group. Table 5.1 shows the two peaks with the greatest m / e values in the mass spectrum of W. Table 5.1 m / e relative abundance x Calculate the relative abundance, x, of the peak at m / e = 75 using the information from Table 5.1. x = The mass spectrum of W also shows peaks at m / e = 29 and m / e = 59. Suggest the molecular formulae of these fragments. m / e = 29 m / e = 59 A sample of W, C4H10O, is heated under reflux with an excess of acidified K2Cr2O7 until there is no further reaction. Only one organic product, X, is present in the mixture at the end of the reaction. shows the infrared spectrum of W. wavenumber / cm–1 transmittance / % A shows the infrared spectrum of X. wavenumber / cm–1 transmittance / % B Table 5.2 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 3200–3650 Absorption A is shown in . Absorption B is shown in . Complete Table 5.3 using the information given in , and Table 5.2. Table 5.3 absorption bond functional group containing the bond A B , , Use the information in and to draw the structure of X in the box in . C4H10O W X acidified K2Cr2O7 + Y is a structural isomer of W. Both W and Y produce colourless bubbles when sodium is added to them. Y does not react when heated with acidified K2Cr2O7. Y does not react when warmed with alkaline I2. Name the functional group present in Y. Complete the equation to describe the reaction of W or Y with sodium. C4H10O + Na Draw the structure of Y. , ,
22. Analytical techniques  →  22.1. Infrared spectroscopy
13. An introduction to AS Level organic chemistry  →  13.1. Formulas, functional groups and the naming of organic compounds
11. Group 17  →  11.2. The chemical properties of the halogen elements and the hydrogen halides
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