9701_s23_qp_21
A paper of Chemistry, 9701
Questions:
5
Year:
2023
Paper:
2
Variant:
1
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1
Tellurium is an element in Group 16. The most common isotope of tellurium is 130Te. Its electronic configuration is [Kr] 4d10 5s2 5p4. Complete Table 1.1. Table 1.1 nucleon number number of neutrons number of electrons 130Te Identify the sub-shell in an atom of Te that contains electrons with the lowest energy. Construct an equation to represent the first ionisation energy of Te. The radius of Te ions decreases after each successive ionisation. State two factors that are responsible for the increase in the first six ionisation energies of Te. Sketch a graph in to show the trend in the first seven ionisation energies of Te. successive ionisation ionisation energy / kJ mol–1 Te reacts with F2 at 150 °C to form TeFx. Molecules of TeFx are octahedral with bond angles of 90°. Explain why TeFx is octahedral with bond angles of 90°. TeFx reacts with water to form tellurium hydroxide and HF. The oxidation number of tellurium does not change during this reaction. Construct an equation for the reaction of TeFx with water. Name the type of reaction that occurs when TeFx reacts with water.
1. Atomic structure  →  1.4. Ionisation energy
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2
A neutralisation reaction occurs when NaOHis added to H2SO4. equation 1 2NaOH+ H2SO4Na2SO4+ 2H2ODefine enthalpy change of neutralisation, ∆Hneut. An experiment is carried out to calculate ∆Hneut for the reaction between NaOHand H2SO4. 100 cm3 of 1.00 mol dm–3 NaOHis added to 75 cm3 of 1.00 mol dm–3 H2SO4in a polystyrene cup and stirred. Results from the experiment are shown in Table 2.1. Table 2.1 initial temperature of NaOH/ °C 20.0 initial temperature of H2SO4/ °C 20.0 maximum temperature of mixture / °C 27.8 Use equation 1 to calculate the amount, in mol, of H2SO4that is neutralised in the experiment. amount of H2SO4neutralised = mol Calculate ∆Hneut using the results in Table 2.1. Include units in your answer. Assume that: • the specific heat capacity of the final solution is 4.18 J g–1 K–1 • 1.00 cm3 of the final solution has a mass of 1.00 g • there is no heat loss to the surroundings • full dissociation of H2SO4occurs • the experiment takes place at constant pressure. Show your working. ∆Hneut = units Complete the equation for the reaction that occurs when a solution of Ba(OH)2 is added to aqueous sulfuric acid. Include state symbols. H2SO4+ Ba(OH)2………………………………………………………… Suggest why the enthalpy change of neutralisation cannot be determined using the addition of dilute sulfuric acid to aqueous barium hydroxide.
5. Chemical energetics  →  5.1. Enthalpy change, \(\Delta H\)
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Chlorine is a very reactive element. Chlorine reacts with silicon to form silicon(chloride. Describe the appearance of silicon(chloride at room temperature and pressure. State its structure and bonding. appearance structure and bonding Samples of magnesium chloride and phosphorus(chloride are added to separate beakers of cold water. Complete Table 3.1. Ignore temperature changes when considering observations for these reactions. Table 3.1 magnesium chloride phosphorus(chloride appearance at room temperature one similarity in observation on addition to cold water one difference in observation on addition to cold water pH of final solution State the reagent and conditions required for the formation of sodium chlorate(from Cl 2. Explain why the reaction in is described as a disproportionation reaction. Your answer should refer to relevant species and their oxidation numbers. Chlorine reacts with methane in a series of reactions to produce chloroalkanes. State the conditions required for chlorine to react with methane. One of the products of the reaction is CH2Cl 2 which reacts further to produce CHCl 3. Complete Table 3.2 to show details of the mechanism that forms CHCl 3 from CH2Cl 2. Table 3.2 name of step equation initiation propagation CH2Cl 2 + Cl • termination CHCl 3 CHCl 3 and HF are used to form CHCl F2 in a substitution reaction. Construct an equation for this reaction. X is a product of the substitution reaction that occurs when CHCl F2 reacts with Br2. There is only one naturally occurring isotope of fluorine, 19F. The mass spectrum of X shows molecular ion peaks at m / e = 164, 166 and 168. Complete Table 3.3 to show all the molecular ions responsible for each peak. Table 3.3 m / e formulae of molecular ions (CF2 37Cl 81Br)+
11. Group 17  →  11.4. The reactions of chlorine
9. The Periodic Table: chemical periodicity  →  9.2. Periodicity of chemical properties of the elements in Period 3
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V is a colourless liquid. V HO O V reacts with an excess of LiAl H4 to form W. Draw the structure of W in the box. W Identify the role of LiAl H4 in the reaction with V. V reacts to form Z in a single reaction, as shown in . V HO O Z HO O OH OH Suggest the reagent and conditions needed to form Z from V. Deduce the empirical formula of Z. Complete Table 4.1 to show the number of sp2 and sp3 hybridised carbon atoms that are present in a molecule of V. Table 4.1 type of hybridisation sp2 sp3 number of carbon atoms in V Q contains the elements carbon, hydrogen and oxygen only. It is a saturated molecule with no branching in its carbon backbone. Q contains only one functional group. The relative molecular mass of Q is 88. No effervescence is seen when Na2CO3 is added to Q. Effervescence is seen when sodium is added to Q. Q reacts with alkaline I2to form a yellow precipitate. Draw the structure of Q in the box. Q
14. Hydrocarbons  →  14.1. Alkanes
14. Hydrocarbons  →  14.2. Alkenes
16. Hydroxy compounds  →  16.1. Alcohols
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Molecule M is present in petrol, a fuel used in cars. M is a saturated, non-cyclic hydrocarbon. M contains eight carbon atoms. Construct an equation for the complete combustion of M. Describe how the composition of products differs when incomplete combustion of M occurs. When petrol is burned in an internal combustion engine, oxides of nitrogen are released into the atmosphere. Oxides of nitrogen are responsible for the formation of acid rain. Suggest the conditions required for the production of oxides of nitrogen during combustion of M in an internal combustion engine. Use an appropriate equation in your answer. Describe how acid rain is formed in the atmosphere in the presence of oxides of nitrogen and SO2. Identify the role of the oxides of nitrogen in this process. Include all relevant equations. State one other type of air pollution that is caused by the production of oxides of nitrogen in an internal combustion engine. Biodiesel T is a fuel made from vegetable oil R. shows the production of T from R in a two-step process. R L HO C O (CH2)8CH3 T H3C C O (CH2)8CH3 step 1 step 2 heat with G + concentrated H2SO4 J + H2C O C O O C O (CH2)8CH3 (CH2)8CH3 H2C O C O HC (CH2)8CH3 O In step 1 all three ester groups in R react. Suggest a suitable reagent and conditions for step 1. Draw the structural formula of J in the box in . Name the type of reaction that occurs in step 2. Name organic reagent G used in step 2. L is called decanoic acid. Use systematic nomenclature to deduce the name of T.
12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur
14. Hydrocarbons  →  14.1. Alkanes
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