9701_s22_qp_22
A paper of Chemistry, 9701
Questions:
6
Year:
2022
Paper:
2
Variant:
2
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1
Magnesium has a melting point of 650 °C and high electrical conductivity. Explain these properties of magnesium by referring to its structure and bonding. When magnesium is heated in air, magnesium oxide, MgO, is the major product. Smaller amounts of magnesiumnitride, Mg3N2, are also made. Calculate the oxidation number for magnesium and for the nitrogen species in Mg3N2 to complete Table 1.1. Table 1.1 species magnesium in Mg3N2 nitrogen in Mg3N2 oxidation number  Identify the type of reaction which takes place between magnesium and nitrogen. Explain your answer. Define enthalpy change of formation. When 3.645 g of Mgburns in excess N2to form Mg3N2, 23.05 kJ of energy is released. Calculate the enthalpy change of formation, ∆Hf, of Mg3N2. Show your working.  ∆Hf (Mg3N2) = 
5. Chemical energetics  →  5.1. Enthalpy change, \(\Delta H\)
10. Group 2  →  10.1. Similarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds
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2
Radium, Ra, is an element found in Group2 of the Periodic Table. It is a crystalline solid at room temperature and conducts electricity. Radiumchloride, RaCl 2, has a melting point of 900 °C and is soluble in water. Predict the lattice structure of RaCl 2based on the properties described. Draw a dot-and-cross diagram to show the arrangement of outer electrons in RaCl 2.  Solid Ra and Ca show similar reactions with H2O, but the reactions occur at different rates. Separate samples, each containing a single piece of solid Ra or Ca, are added to equal volumes of cold water. Each sample contains equal numbers of moles of solid and the H2O is in excess. Construct an equation for the reaction of Ra with H2O. Identify which element, Ra or Ca, reacts with H2O at a faster rate. Suggest how the observations of each reaction would differ. Suggest why these reactions occur at different rates. One of the solutions is cloudy when the reaction has finished. At the end of each reaction, universal indicator is added to each reaction mixture. Suggest pH values of the solutions made in both reactions. Explain your answer. A sample of aqueous calcium halide, CaX2, contains either chloride, bromide or iodide ions. Complete Table2.1 to describe a two-step process that could be used to identify the halide ion present. Table 2.1 step method observation with CaCl 2 observation with CaBr2 observation with CaI2 step 1 step 2  
11. Group 17  →  11.3. Some reactions of the halide ions
9. The Periodic Table: chemical periodicity  →  9.2. Periodicity of chemical properties of the elements in Period 3
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0.025 mol of HIis added to a closed vessel and left to reach dynamic equilibrium. The total pressure of the vessel is 100 kPa. equation 1 2HIH2+ I2Explain what is meant by dynamic equilibrium. Describe one difference in the initial appearance of the reaction mixture compared to the mixture at equilibrium. Write an expression for Kp for the reaction described in equation1. Kp =  At equilibrium the partial pressure of HIis 86.4 kPa. Calculate the amount of HIpresent in the mixture at equilibrium. Show your working.  amount of HI= mol Use equation1 and the bond energy values in Table3.1 to calculate the change in enthalpy, ∆H, for the thermal decomposition of 1mole of HI. Show your working. Table 3.1 bond bond energy / kJ mol–1 H–H I–I H–I  ∆H = kJ mol–1 Describe the effect of increasing pressure on the value of Kp for the decomposition of HI. HCl is prepared by adding NaCl to concentrated H2SO4. HIis not prepared by adding NaIto concentrated H2SO4 because the HIproduced also reacts with concentrated H2SO4. Identify the type of reaction that occurs when NaIreacts with concentrated H2SO4 to form HI. Write an equation for the reaction of HIand concentrated H2SO4. Explain why HIreacts with concentrated H2SO4 whereas HCl does not. 
5. Chemical energetics  →  5.1. Enthalpy change, \(\Delta H\)
7. Equilibria  →  7.1. Chemical equilibria: reversible reactions, dynamic equilibrium
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Bromine reacts with butane in the presence of ultraviolet light to form bromobutane. Two structural isomers with the molecular formula C4H9Br are produced during this reaction. Draw the two structural isomers and state the systematic name of each isomer. structural isomer 1 name structural isomer 2 name  Identify the type of structural isomerism shown in . Halothane is an anaesthetic. F C F F C halothane Cl Br H Identify the chiral centre in halothane and mark it with an asterisk (*). When halothane reacts in ultraviolet light, homolytic fission occurs and the C–Br bond is broken. Construct an equation to show the homolytic fission of halothane, CF3CHBrCl. Complete Fig.4.2 to show the arrangement of electrons in a bromine atom using the electrons in boxes notation. 3d [Ar] 4p 4s  X is an addition polymer. Cl X n Draw the monomer of X.  Suggest one reason why the disposal of items made from X is difficult. 
14. Hydrocarbons  →  14.2. Alkenes
14. Hydrocarbons  →  14.1. Alkanes
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5
Fig.5.1 shows three reactions of 2-bromopropane, CH3CH(Br)CH3. CH3CH(Br)CH3 CH3CH(NH2)CH3 CH3CH(OH)CH3 H2C=CHCH3 reaction 1 reaction 3 reaction 2 Complete Table5.1 for each reaction, by: ● stating the reagent and conditions used ● identifying the type of reaction that occurs. Table 5.1 reaction reagent and conditions type of reaction  A sample of 2-iodopropane, CH3CH(CH3, reacts under the same conditions as reaction1 to produce CH3CH(OH)CH3. Explain why 2-iodopropane reacts at a faster rate than 2-bromopropane. Fig.5.2 shows how butan-1-ol can be made from 1-bromopropane in three steps. Br step 1 step 2 step 3 N HO HO O In step1, 1-bromopropane reacts with CN– to form butanenitrile. Complete Fig.5.3 to show the mechanism for step1. Include charges, dipoles, lone pairs of electrons and curly arrows as appropriate. H C H H C H H C H H Br H C H H C H H C H H C N C– N Br –  In step2, butanenitrile is heated with HCl . A hydrolysis reaction occurs. Construct an equation for the reaction in step2. Step3 is a reduction reaction. Construct an equation for the reduction reaction in step3. Use [H] to represent one atom of hydrogen from the reducing agent. State the identity of a suitable reducing agent in step3. 
15. Halogen compounds  →  15.1. Halogenoalkanes
14. Hydrocarbons  →  14.2. Alkenes
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Z is a molecule which contains the elements carbon, hydrogen and oxygen only. Z contains only alkene and carboxyl functional groups. Complete Table6.1 by describing the observations that occur when two different reagents are added to separate samples of Z. Table 6.1 reagent added to Zobservation Br2Na2CO3 Table6.2 shows the percentage by mass of each element present in Z. Table 6.2 element percentage by mass / % carbon 41.38 hydrogen 3.45 oxygen 55.17 Using the data in Table6.2, demonstrate that the empirical formula of Z is CHO. Show your working.  Fig.6.1 shows the mass spectrum of Z. relative abundance m / e Deduce the molecular formula of Z. Explain your answer by referring to the molecular ion peak in Fig.6.1 and the empirical formula of Z.  Use Fig.6.1 to suggest the formulae of the fragments with m / e peaks at 45 and at 71. m / e 45 m / e 71  Suggest the structure of Z using relevant information from Table6.1, and .  
22. Analytical techniques  →  22.2. Mass spectrometry
2. Atoms, molecules and stoichiometry  →  2.3. Formulas
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