9701_s20_qp_23
A paper of Chemistry, 9701
Questions:
5
Year:
2020
Paper:
2
Variant:
3
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1
A sample of barium is heated in oxygen. Describe two observations for this reaction. Write an equation for this reaction. Include state symbols. Calciumcarbonate can be converted into calciumhydroxide in a two-step process. calcium carbonate step 1 calcium oxide step 2 calcium hydroxide Describe how the two-step process is carried out to convert calcium carbonate into calciumhydroxide. Include relevant equations. Name the type of reaction occurring when calcium carbonate is converted into calciumoxide. State one common use for both calciumcarbonate and calciumhydroxide. Gallium is a silver-grey solid. Aluminium and gallium share many similar chemical properties. Construct an equation for the reaction of gallium when heated in oxygen to form galliumoxide, Ga2O3. Deduce the oxidation number of gallium in Ga2O3. Complete the table by predicting the formula of each gallium-containing product formed when galliumoxide reacts separately with hot aqueous hydrochloricacid and with hot concentrated sodiumhydroxide. reagents and conditions formula of gallium-containing product gallium oxide + hot HCl gallium oxide + hot concentrated NaOH 
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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Explain what is meant by the term relative isotopic mass. A sample of copper contains two isotopes, 63Cu and 65Cu. The relative atomic mass of the copper in this sample is 63.55. Calculate the percentage abundance of each of these isotopes. Show your working.  percentage abundance of 63Cu = %  percentage abundance of 65Cu = %  Name the type of bonding within a sample of solid copper. Draw a labelled diagram to show the bonding within a sample of solid copper.  State the electronic configuration of a copper atom. 1s2 A student is provided with a sample of hydrated copper(sulfate, CuSO4•xH2O, and is asked to determine the value of x. The student dissolves a sample of the hydrated copper(sulfate in water and adds it to an excess of aqueous potassiumiodide to make a total volume of 250.0 cm3 of solution. 2CuSO4 + 4KI → 2CuI + I2 + K2SO4 The amount of iodine produced during this reaction is found by titrating a sample of this solution with sodiumthiosulfate solution. 25.0 cm3 of the iodine-containing solution requires 20.0 cm3 of 0.10 mol dm–3 sodiumthiosulfate solution. I2 + 2S2O3 2– → S4O6 2– + 2I– Calculate the amount, in mol, of copper(sulfate present in the original sample of hydrated copper(sulfate. Show your working.  amount of copper(sulfate = mol A total of 7.98 g of CuSO4 is present in 10.68 g of CuSO4•xH2O. Complete each row of the table to calculate the value of x, where x is an integer. [Mr: CuSO4,159.6] amount of CuSO4 in 10.68 g of CuSO4•xH2O mol amount of H2O in 10.68 g of CuSO4•xH2O mol value of x x =  
2. Atoms, molecules and stoichiometry  →  2.1. Relative masses of atoms and molecules
22. Analytical techniques  →  22.2. Mass spectrometry
1. Atomic structure  →  1.2. Isotopes
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Sucrose is a white crystalline solid, C12H22O11. In reaction Z, sucrose reacts with water in the presence of a catalyst, aqueous hydrochloricacid, to form glucose and fructose. C12H22O11 + H2O + glucose fructose reaction Z C CH2OH OH H C OH H C C OH H C H H O HO C CH2OH OH H C OH H C C H CH2OH O HO Suggest a name for the reaction that occurs when sucrose reacts with water to form glucose and fructose. If no catalyst is added in reaction Z, the reaction is very slow. Label the Boltzmann distribution to show the effect of adding a catalyst to the sample of sucrose and water molecules at constant temperature. number of sucrose molecules energy Explain your labelled diagram.  Both fructose and glucose contain chiral centres. Explain what is meant by the term chiral centre. On the diagram of the fructose molecule, label all the chiral centres with an asterisk (*). C H O C C H O H C H H H H C O O O H H C H O H H  Determine the empirical formula of fructose. Explain what is meant by the term enthalpy change of combustion. Write the equation for the complete combustion of sucrose. The enthalpy change of reaction Z, ∆Hr, can be calculated using the enthalpy change of combustion data given in the table. substance enthalpy change of combustion, ∆Hc / kJ mol–1 sucrose –5643 glucose –2805 fructose –2810 Use the data in the table to calculate the enthalpy change for the reaction occurring when sucrose reacts with water, ∆Hr. You should draw a labelled Hess’ cycle to show your working.  ∆Hr = kJ mol–1 
5. Chemical energetics  →  5.1. Enthalpy change, \(\Delta H\)
8. Reaction kinetics  →  8.2. Effect of temperature on reaction rates and the concept of activation energy
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Hexane, C6H14, is a colourless liquid. Two test-tubes contain equal amounts of hexane. 1 cm3 of bromine, Br2, is added to both test‑tubes. One test-tube is kept in the dark and the other is exposed to sunlight. The table describes the appearance of each test-tube after one hour. test-tube conditions observations in the dark no change, mixture remains orange in sunlight colour of mixture fades to pale yellow The test-tube in the dark is kept cool and is not exposed to ultraviolet light. Explain the observations for the test-tube kept in the dark. In sunlight, bromine reacts with hexane by a mechanism which occurs via a series of steps. State the name of the mechanism of the reaction that occurs. Give an equation which shows a propagation step in this reaction in which hexane produces •C6H13. Give an equation which shows a propagation step in this reaction that produces 1-bromohexane. Give an equation which shows a termination step in this reaction that produces 1-bromohexane. A and B are different straight chain alkenes with molecular formula, C6H12. A does not show stereoisomerism. A reacts with potassiummanganate(to form hexane-1,2-diol. Draw the structural formula of A.  State the conditions needed for this reaction of A. B reacts with hydrogen gas in the presence of a platinum catalyst to produce hexane. Name the type of reaction occurring. In terms of σ and π bonds, describe any similarities and differences in the type of carbon‑carbon bonds in B and the type of carbon‑carbon bonds in hexane. 
14. Hydrocarbons  →  14.1. Alkanes
14. Hydrocarbons  →  14.2. Alkenes
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C, D and E are isomers of each other. They are made by passing an alcohol vapour over an aluminium oxide catalyst. C D E Name the type of reaction occurring. Draw the displayed formula of the alcohol used in this reaction.  Name the isomers C, D and E. isomer name C D E  F is an organic molecule which has the molecular formula C3H6O2. When F is heated with NaOHfollowed by H2SO4the products G and H are made. F C3H6O2 G H NaOHfollowed by H2SO4+ Separate samples of G and H are added to ● ● Na2CO3● ● sodium metal ● ● alkaline aqueous iodine. The observations are described in the table. reagentG H Na2CO3colourless bubbles of gas produced no visible reaction Nacolourless bubbles of gas produced colourless bubbles of gas produced alkaline aqueous iodine no visible reaction yellow precipitate forms Complete the table to identify the functional groups present in F, G and H. functional group F G H  Name the yellow precipitate formed when alkaline aqueous iodine reacts with H. Draw the structures of G and H. G H  
16. Hydroxy compounds  →  16.1. Alcohols
17. Carbonyl compounds  →  17.1. Aldehydes and ketones
14. Hydrocarbons  →  14.2. Alkenes
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