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HL Paper 2

The photochemical chlorination of methane can occur at low temperature.

The overall equation for monochlorination of methane is:

CH4(g) + Cl2(g) → CH3Cl(g) + HCl(g)

Calculate the standard enthalpy change for the reaction, ΔH θ, using section 12 of the data booklet.




Propene is an important starting material for many products. The following shows some compounds which can be made from propene, C3H6.


Propene (C3H6) → C3H7Cl → C3H8O → C3H6O

Consider the conversion of propene to C3H7Cl.

An experiment was carried out to determine the order of reaction between one of the isomers of C3H7Cl and aqueous sodium hydroxide. The following results were obtained.

State the type of reaction.

[1]
a(i).

State the IUPAC name of the major product.

[1]
a(ii).

Outline why it is the major product.

[1]
a(iii).

Write an equation for the reaction of the major product with aqueous sodium hydroxide to produce a C3H8O compound, showing structural formulas.

[1]
a(iv).

Determine the rate expression from the results, explaining your method.

[3]
b(i).

Deduce the type of mechanism for the reaction of this isomer of C3H7Cl with aqueous sodium hydroxide.

[1]
b(ii).

Sketch the mechanism using curly arrows to represent the movement of electrons.

[4]
b(iii).

Write an equation for the complete combustion of the compound C3H8O formed in (a)(iv).

[1]
c(i).

Determine the enthalpy of combustion of this compound, in kJ mol−1, using data from section 11 of the data booklet.

[3]
c(ii).

State the reagents for the conversion of the compound C3H8O formed in (a)(iv) into C3H6O.

[1]
d(i).

Explain why the compound C3H8O, produced in (a)(iv), has a higher boiling point than compound C3H6O, produced in d(i).

[2]
d(ii).

Explain why the 1H NMR spectrum of C3H6O, produced in (d)(i), shows only one signal.

[1]
d(iii).

Propene is often polymerized. Draw a section of the resulting polymer, showing two repeating units.

[1]
e.



Organomagnesium compounds can react with carbonyl compounds. One overall equation is:

Compound B can also be prepared by reacting an alkene with water.

Iodomethane is used to prepare CH3MgI. It can also be converted into methanol:

CH3I + HO → CH3OH + I

State the name of Compound B, applying International Union of Pure and Applied Chemistry (IUPAC) rules.

[1]
a(i).

Compound A and Compound B are both liquids at room temperature and pressure. Identify the strongest intermolecular force between molecules of Compound A.

[1]
a(ii).

State the number of σ (sigma) and π (pi) bonds in Compound A.

[1]
a(iii).

Deduce the hybridization of the central carbon atom in Compound A.

[1]
a(iv).

Identify the isomer of Compound B that exists as optical isomers (enantiomers).

[1]
a(v).

Draw the structural formula of the alkene required.

[1]
b(i).

Explain why the reaction produces more (CH3)3COH than (CH3)2CHCH2OH.

[2]
b(ii).

Deduce the structural formula of the repeating unit of the polymer formed from this alkene.

[1]
b(iii).

Deduce what would be observed when Compound B is warmed with acidified aqueous potassium dichromate (VI).

[1]
c.

Identify the type of reaction.

[1]
d(i).

Outline the requirements for a collision between reactants to yield products.

[2]
d(ii).

Explain the mechanism of the reaction using curly arrows to represent the movement of electron pairs.

[3]
d(iii).

The polarity of the carbon–halogen bond, C–X, facilitates attack by HO.

Outline, giving a reason, how the bond polarity changes going down group 17.

[1]
d(iv).



Benzoic acid, C6H5COOH, is another derivative of benzene.

Identify the wavenumber of one peak in the IR spectrum of benzoic acid, using section 26 of the data booklet.

[1]
a.

Identify the spectroscopic technique that is used to measure the bond lengths in solid benzoic acid.

[1]
b.

Outline one piece of physical evidence for the structure of the benzene ring.

[1]
c.

Draw the structure of the conjugate base of benzoic acid showing all the atoms and all the bonds.

[1]
d.

Outline why both C to O bonds in the conjugate base are the same length and suggest a value for them. Use section 10 of the data booklet.

[2]
e.

The pH of an aqueous solution of benzoic acid at 298 K is 2.95. Determine the concentration of hydroxide ions in the solution, using section 2 of the data booklet.

[2]
f(i).

Formulate the equation for the complete combustion of benzoic acid in oxygen using only integer coefficients.

[2]
f(ii).

The combustion reaction in (f)(ii) can also be classed as redox. Identify the atom that is oxidized and the atom that is reduced.

[1]
g.

Suggest how benzoic acid, Mr = 122.13, forms an apparent dimer, Mr = 244.26, when dissolved in a non-polar solvent such as hexane.

[1]
h.

State the reagent used to convert benzoic acid to phenylmethanol (benzyl alcohol), C6H5CH2OH.

[1]
i.



Organic compounds often have isomers.

A straight chain molecule of formula C5H10O contains a carbonyl group. The compound cannot be oxidized by acidified potassium dichromate(VI) solution.

A tertiary halogenoalkane with three different alkyl groups, (R1R2R3)C−X, undergoes a SN1 reaction and forms two isomers.

Deduce the structural formulas of the two possible isomers.

[2]
a.i.

Mass spectra A and B of the two isomers are given.

M18/4/CHEMI/HP2/ENG/TZ2/09.a.ii_01

Explain which spectrum is produced by each compound using section 28 of the data booklet.

 

[2]
a.ii.

State the type of bond fission that takes place in a SN1 reaction.

[1]
b.i.

State the type of solvent most suitable for the reaction.

[1]
b.ii.

Draw the structure of the intermediate formed stating its shape.

[2]
b.iii.

Suggest, giving a reason, the percentage of each isomer from the SN1 reaction.

[2]
b.iv.

Nitrobenzene, C6H5NO2, can be converted to phenylamine via a two-stage reaction.

In the first stage, nitrobenzene is reduced with tin in an acidic solution to form an intermediate ion and tin(II) ions. In the second stage, the intermediate ion is converted to phenylamine in the presence of hydroxide ions.

Formulate the equation for each stage of the reaction.

 

[2]
c.



This question is about ethene, C2H4, and ethyne, C2H2.

Ethyne, like ethene, undergoes hydrogenation to form ethane. State the conditions required.

[2]
a.i.

Outline the formation of polyethene from ethene by drawing three repeating units of the polymer.

[1]
a.ii.

Ethyne reacts with chlorine in a similar way to ethene. Formulate equations for the following reactions.

 

[2]
b.

Under certain conditions, ethyne can be converted to benzene.

Determine the standard enthalpy change, ΔHΘ, for the reaction stated, using section 11 of the data booklet.

3C2H2(g) → C6H6(g)

[2]
c.i.

Determine the standard enthalpy change, ΔHΘ, for the following similar reaction, using ΔHf values in section 12 of the data booklet.

3C2H2(g) → C6H6(l)

[2]
c.ii.

Explain, giving two reasons, the difference in the values for (c)(i) and (ii). If you did not obtain answers, use −475 kJ for (i) and −600 kJ for (ii).

[2]
c.iii.

Calculate the standard entropy change, ΔSΘ, in J K−1, for the reaction in (ii) using section 12 of the data booklet.

[1]
c.iv.

Determine, showing your working, the spontaneity of the reaction in (ii) at 25 °C.

[3]
c.v.

One possible Lewis structure for benzene is shown.

M18/4/CHEMI/HP2/ENG/TZ1/03.d

State one piece of physical evidence that this structure is incorrect.

[1]
d.



Carbon forms many compounds.

C60 and diamond are allotropes of carbon.

Chlorine reacts with methane.

CH4 (g) + Cl2 (g) → CH3Cl (g) + HCl (g)

Outline two differences between the bonding of carbon atoms in C60 and diamond.

[2]
a(i).

Explain why C60 and diamond sublime at different temperatures and pressures.

[2]
a(ii).

State two features showing that propane and butane are members of the same homologous series.

[2]
b.

Describe a test and the expected result to indicate the presence of carbon–carbon double bonds.

[2]
c.

Draw the full structural formula of (Z)-but-2-ene.

[1]
d(i).

Write the equation for the reaction between but-2-ene and hydrogen bromide.

[1]
d(ii).

State the type of reaction.

[1]
d(iii).

Suggest two differences in the 1H NMR of but-2-ene and the organic product from (d)(ii).

[2]
d(iv).

Predict, giving a reason, the major product of reaction between but-1-ene and steam.

[2]
d(v).

Explain the mechanism of the reaction between 1-bromopropane, CH3CH2CH2Br, and aqueous sodium hydroxide, NaOH (aq), using curly arrows to represent the movement of electron pairs.

[4]
e(i).

Deduce the splitting pattern in the 1H NMR spectrum for 1-bromopropane.

[1]
e(ii).

Calculate the enthalpy change of the reaction, ΔH, using section 11 of the data booklet.

[3]
f(i).

Draw and label an enthalpy level diagram for this reaction.

[2]
f(ii).



This question is about carbon and chlorine compounds.

Ethane, C 2 H 6 , reacts with chlorine in sunlight. State the type of this reaction and the name of the mechanism by which it occurs.

M17/4/CHEMI/HP2/ENG/TZ1/06.a

[1]
a.

Formulate equations for the two propagation steps and one termination step in the formation of chloroethane from ethane.

M17/4/CHEMI/HP2/ENG/TZ1/06.bi

[3]
b.i.

Deduce the splitting patterns in the 1H NMR spectrum of C2H5Cl.

[1]
b.ii.

Explain why tetramethylsilane (TMS) is often used as a reference standard in 1H NMR.

[2]
b.iii.

One possible product, X, of the reaction of ethane with chlorine has the following composition by mass:

carbon: 24.27%, hydrogen: 4.08%, chlorine: 71.65%

Determine the empirical formula of the product.

[2]
c.i.

The mass and 1H NMR spectra of product X are shown below. Deduce, giving your reasons, its structural formula and hence the name of the compound.

[3]
c.ii.

When the product X is reacted with NaOH in a hot alcoholic solution, C2H3Cl is formed. State the role of the reactant NaOH other than as a nucleophile.

[1]
c.iii.

Chloroethene, C 2 H 3 Cl , can undergo polymerization. Draw a section of the polymer with three repeating units.

[1]
d.



Carbon dioxide contributes significantly to global warming. It can be used as a raw material with methyloxirane to form polymers.

Suggest why the three-membered ring in methyloxirane is unstable.

[1]
a.

Draw two structural isomers of methyloxirane.

[2]
b.i.

State, giving a reason, whether methyloxirane can form cis-trans isomers.

[1]
b.ii.

Predict the chemical shift and splitting pattern of the signal produced by the hydrogen atoms labelled X in the 1H NMR spectrum of the polymer. Use section 27 of the data booklet.

[2]
c.



An organic compound containing carbon, hydrogen and oxygen has 62.02 % carbon and 10.43 % hydrogen by mass.

Determine the empirical formula of the compound, showing your working.

[3]
a.

The infrared spectrum of the compound is shown. Deduce the functional group of the compound.

[1]
b.

The mass spectrum of the compound is shown. Deduce the relative molecular mass of the compound.

[1]
c.

The compound could not be oxidized using acidifi ed potassium dichromate(VI).

Deduce the structural formula of the compound.

[1]
d.



This question is about the reactions of halogenoalkanes.

Compare and contrast the mechanisms by which 1-chlorobutane, CH3CH2CH2CH2Cl, and 2-chloro-2-methylpropane, (CH3)3CCl, react with aqueous sodium hydroxide, giving two similarities and one difference.

 

[3]
a.

Outline why the rate of reaction of the similar bromo-compounds is faster.

[1]
b.

State the organic product of the reaction between 1-chlorobutane, CH3CH2CH2CH2Cl, and aqueous sodium hydroxide.

[1]
c.i.

Suggest how this product could be synthesized in one step from butanoic acid.

[1]
c.ii.

Deduce the name of the class of compound formed when the product of (c)(i) reacts with butanoic acid.

[1]
c.iii.



A compound with a molecular formula C7H14O produced the following high resolution 1H NMR spectrum.

Deduce what information can be obtained from the 1H NMR spectrum.

[3]
a.i.

Identify the functional group that shows stretching at 1710 cm–1 in the infrared spectrum of this compound using section 26 of the data booklet and the 1H NMR.

[1]
a.ii.

Suggest the structural formula of this compound.

[2]
a.iii.

Bromine was added to hexane, hex-1-ene and benzene. Identify the compound(s) which will react with bromine in a well-lit laboratory.

[1]
b.i.

Deduce the structural formula of the main organic product when hex-1-ene reacts with hydrogen bromide.

[1]
b.ii.

State the reagents and the name of the mechanism for the nitration of benzene.

[2]
c.i.

Outline, in terms of the bonding present, why the reaction conditions of halogenation are different for alkanes and benzene.

[1]
c.ii.

Below are two isomers, A and B, with the molecular formula C4H9Br.

Explain the mechanism of the nucleophilic substitution reaction with NaOH(aq) for the isomer that reacts almost exclusively by an SN2 mechanism using curly arrows to represent the movement of electron pairs.

[3]
d.



The Bombardier beetle sprays a mixture of hydroquinone and hydrogen peroxide to fight off predators. The reaction equation to produce the spray can be written as:

C6H4(OH)2(aq) + H2O2(aq) C6H4O2(aq) + 2H2O(l)
hydroquinone   quinone


 

Hydrogenation of propene produces propane. Calculate the standard entropy change, ΔSθ, for the hydrogenation of propene.

[2]
b.i.

The standard enthalpy change, ΔH θ, for the hydrogenation of propene is –124.4 kJ mol–1. Predict the temperature above which the hydrogenation reaction is not spontaneous.

[2]
b.ii.



Nickel catalyses the conversion of propanone to propan-2-ol.

Outline how a catalyst increases the rate of reaction.

[1]
a.

Explain why an increase in temperature increases the rate of reaction.

[2]
b.

Discuss, referring to intermolecular forces present, the relative volatility of propanone and propan-2-ol.

[3]
c.

The diagram shows an unlabelled voltaic cell for the reaction

Pb2+(aq)+Ni(s)Ni2+(aq)+Pb(s)

Label the diagram with the species in the equation.

[1]
d(i).

Calculate the standard cell potential, in V, for the cell at 298K. Use section 24 of the data booklet

[1]
d(ii).

Calculate the standard free energy change, G, in kJ, for the cell using sections 1 and 2 of the data booklet.

[1]
d(iii).

Suggest a metal that could replace nickel in a new half-cell and reverse the electron flow. Use section 25 of the data booklet.

[1]
d(iv).

Describe the bonding in metals.

[2]
d(v).

Nickel alloys are used in aircraft gas turbines. Suggest a physical property altered by the addition of another metal to nickel.

[1]
d(vi).



An acidic sample of a waste solution containing Sn2+(aq) reacted completely with K2Cr2O7 solution to form Sn4+(aq).

Identify one organic functional group that can react with acidified K2Cr2O7(aq).

[1]
a.v.

Corrosion of iron is similar to the processes that occur in a voltaic cell. The initial steps involve the following half-equations:

Fe2+(aq) + 2e Fe(s)

1 2 O2(g) + H2O(l) + 2e 2OH(aq)

Calculate Eθ, in V, for the spontaneous reaction using section 24 of the data booklet.

[1]
b.i.

Calculate the Gibbs free energy, ΔGθ, in kJ, which is released by the corrosion of 1 mole of iron. Use section 1 of the data booklet.

[2]
b.ii.

Explain why iron forms many different coloured complex ions.

[3]
b.iii.

Zinc is used to galvanize iron pipes, forming a protective coating. Outline how this process prevents corrosion of the iron pipes.

[1]
c.



Halogenoalkanes undergo nucleophilic substitution reactions with sodium hydroxide.

State a reason why most halogenoalkanes are more reactive than alkanes.

[1]
a.

Classify 1-bromopropane as a primary, secondary or tertiary halogenoalkane, giving a reason.

[1]
b.

Explain the mechanism of the reaction between 1-bromopropane with aqueous sodium hydroxide using curly arrows to represent the movement of electron pairs.

[4]
c.

State, giving your reason, whether the hydroxide ion acts as a Lewis acid, a Lewis base, or neither in the nucleophilic substitution.

[1]
d.

Suggest two advantages of understanding organic reaction mechanisms.

[2]
e.



Xylene is a derivative of benzene. One isomer is 1,4-dimethylbenzene.

Xylene, like benzene, can be nitrated.

Bromine reacts with alkanes.

State the number of 1H NMR signals for this isomer of xylene and the ratio in which they appear.

 

[2]
a.

Draw the structure of one other isomer of xylene which retains the benzene ring.

[1]
b.

Write the equation for the production of the active nitrating agent from concentrated sulfuric and nitric acids.

[1]
c(i).

Explain the mechanism for the nitration of benzene, using curly arrows to indicate the movement of electron pairs.

[4]
c(ii).

Identify the initiation step of the reaction and its conditions.

[2]
d(i).

1,4-dimethylbenzene reacts as a substituted alkane. Draw the structures of the two products of the overall reaction when one molecule of bromine reacts with one molecule of 1,4-dimethylbenzene.

[2]
d(ii).

The organic product is not optically active. Discuss whether or not the organic product is a racemic mixture.

[1]
e.



Ethanol is obtained by the hydration of ethene, C2H4.

Alternative synthetic routes exist to produce alcohols.

Ethanol is obtained by the hydration of ethene, C2H4.

State the class of compound to which ethene belongs.

[1]
a(i).

State the molecular formula of the next member of the homologous series to which ethene belongs.

[1]
a(ii).

Justify why ethene has only a single signal in its 1H NMR spectrum.

[1]
b(i).

Deduce the chemical shift of this signal. Use section 27 of the data booklet.

[1]
b(ii).

Suggest two possible products of the incomplete combustion of ethene that would not be formed by complete combustion.

[1]
c.

A white solid was formed when ethene was subjected to high pressure.

Deduce the type of reaction that occurred.

[1]
d.

Sketch the mechanism for the reaction of propene with hydrogen bromide using curly arrows.

[3]
e(i).

Explain why the major organic product is 2-bromopropane and not 1-bromopropane.

[2]
e(ii).

Explain why the major organic product is 2-bromopropane and not 1-bromopropane.

[2]
e(ii).

2-bromopropane can be converted directly to propan-2-ol. Identify the reagent required.

[1]
e(iii).

Propan-2-ol can also be formed in one step from a compound containing a carbonyl group.

State the name of this compound and the type of reaction that occurs.

[2]
e(iv).



Ethyne, C2H2, reacts with oxygen in welding torches.

Ethyne reacts with steam.

C2H2 (g) + H2O (g) → C2H4O (g)

Two possible products are:

Product B, CH3CHO, can also be synthesized from ethanol.

Write an equation for the complete combustion of ethyne.

[1]
a.

Deduce the Lewis (electron dot) structure of ethyne.

[1]
b(i).

Compare, giving a reason, the length of the bond between the carbon atoms in ethyne with that in ethane, C2H6.

[1]
b(ii).

Identify the type of interaction that must be overcome when liquid ethyne vaporizes.

[1]
b(iii).

State the name of product B, applying IUPAC rules.

[1]
c(i).

Determine the enthalpy change for the reaction, in kJ, to produce A using section 11 of the data booklet.

[3]
c(ii).

The enthalpy change for the reaction to produce B is −213 kJ.

Predict, giving a reason, which product is the most stable.

[1]
c(iii).

The IR spectrum and low resolution 1H NMR spectrum of the actual product formed are shown.

Deduce whether the product is A or B, using evidence from these spectra together with sections 26 and 27 of the  data booklet.

Identity of product:

One piece of evidence from IR:

One piece of evidence from 1H NMR:

 

[2]
c(iv).

Deduce the splitting pattern you would expect for the signals in a high resolution 1H NMR spectrum.

2.3 ppm:

9.8 ppm:

[2]
c(v).

Suggest the reagents and conditions required to ensure a good yield of product B.

Reagents: 

Conditions:

[2]
d(i).

Deduce the average oxidation state of carbon in product B.

[1]
d(ii).

Explain why product B is water soluble.

[3]
d(iii).



Ethanol and methanoic acid are important industrial products.

Ethanol is used as a fuel.

Write the chemical equation for the complete combustion of ethanol.

[1]
a(i).

Deduce the change in enthalpy, ΔH, in kJ, when 56.00 g of ethanol is burned. Use section 13 in the data booklet.

[2]
a(ii).

Oxidation of ethanol with potassium dichromate, K2Cr2O7, can form two different organic products. Determine the names of the organic products and the methods used to isolate them.

[2]
b.

Write the equation and name the organic product when ethanol reacts with methanoic acid.

[2]
c.

Sketch the titration curve of methanoic acid with sodium hydroxide, showing how you would determine methanoic acid pKa.

[2]
d(i).

Identify an indicator that could be used for the titration in 5(d)(i), using section 22 of the data booklet.

[1]
d(ii).

Determine the concentration of methanoic acid in a solution of pH = 4.12. Use section 21 of the data booklet.

[2]
e.

Identify if aqueous solutions of the following salts are acidic, basic, or neutral.

[2]
f.



Benzene is an aromatic hydrocarbon.

Discuss the physical evidence for the structure of benzene.

[2]
a.

State the typical reactions that benzene and cyclohexene undergo with bromine.

M17/4/CHEMI/HP2/ENG/TZ1/07.b

[1]
b.

State the reagents used to convert benzene to nitrobenzene and the formula of the electrophile formed.

[2]
c.

Explain the mechanism for the nitration of benzene, using curly arrows to show the movement of electron pairs.

[4]
d.

State the reagents used in the two-stage conversion of nitrobenzene to aniline.

[2]
e.



Chlorine undergoes many reactions.

2.67g of manganese(IV) oxide was added to 200.0cm3 of 2.00moldm-3 HCl.

MnO2(s)+4HCl(aq)Cl2(g)+2H2O(l)+MnCl2(aq)

Chlorine gas reacts with water to produce hypochlorous acid and hydrochloric acid.

Cl2(g)+H2O(l)HClO(aq)+HCl(aq)

CCl2F2 is a common chlorofluorocarbon, CFC.

State the full electron configuration of the chlorine atom.

[1]
a(i).

State, giving a reason, whether the chlorine atom or the chloride ion has a larger radius.

[1]
a(ii).

Outline why the chlorine atom has a smaller atomic radius than the sulfur atom.

[2]
a(iii).

The mass spectrum of chlorine is shown.

NIST Mass Spectrometry Data Center Collection © 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.


Outline the reason for the two peaks at m/z=35 and 37.

[1]
a(iv).

Explain the presence and relative abundance of the peak at m/z=74.

[2]
a(v).

Calculate the amount, in mol, of manganese(IV) oxide added.

[1]
b(i).

Determine the limiting reactant, showing your calculations.

[2]
b(ii).

Determine the excess amount, in mol, of the other reactant.

[1]
b(iii).

Calculate the volume of chlorine, in dm3, produced if the reaction is conducted at standard temperature and pressure (STP). Use section 2 of the data booklet.

[1]
b(iv).

State the oxidation state of manganese in MnO2 and MnCl2.

[2]
b(v).

Deduce, referring to oxidation states, whether MnO2 is an oxidizing or reducing agent.

[1]
b(vi).

Hypochlorous acid is considered a weak acid. Outline what is meant by the term weak acid.

 

[1]
c(i).

State the formula of the conjugate base of hypochlorous acid.

[1]
c(ii).

Calculate the concentration of H+(aq) in a HClOaq solution with a pH=3.61.

[1]
c(iii).

State the type of reaction occurring when ethane reacts with chlorine to produce chloroethane.

[1]
d(i).

Predict, giving a reason, whether ethane or chloroethane is more reactive.

[1]
d(ii).

Explain the mechanism of the reaction between chloroethane and aqueous sodium hydroxide, NaOH(aq), using curly arrows to represent the movement of electron pairs.

[3]
d(iii).

Ethoxyethane (diethyl ether) can be used as a solvent for this conversion.
Draw the structural formula of ethoxyethane

[1]
d(iv).

Deduce the number of signals and chemical shifts with splitting patterns in the 1H NMR spectrum of ethoxyethane. Use section 27 of the data booklet.

[3]
d(v).

Calculate the percentage by mass of chlorine in CCl2F2.

[2]
e(i).

Comment on how international cooperation has contributed to the lowering of CFC emissions responsible for ozone depletion.

[1]
e(ii).

CFCs produce chlorine radicals. Write two successive propagation steps to show how chlorine radicals catalyse the depletion of ozone.

[2]
e(iii).



Organic chemistry can be used to synthesize a variety of products.

Combustion analysis of an unknown organic compound indicated that it contained only carbon, hydrogen and oxygen.

Several compounds can be synthesized from but-2-ene. Draw the structure of the final product for each of the following chemical reactions.

[2]
a.

Determine the change in enthalpy, ΔH, for the combustion of but-2-ene, using section 11 of the data booklet. 

CH3CH=CHCH3 (g) + 6O2 (g) → 4CO2 (g) + 4H2O (g)

[3]
b.

State the hybridization of the carbon I and II atoms in but-2-ene.

[1]
c.

Draw diagrams to show how sigma (σ) and pi (π) bonds are formed between atoms.

[2]
d.

Sketch the mechanism for the reaction of 2-methylbut-2-ene with hydrogen bromide using curly arrows.

[3]
e.

Explain why the major organic product is 2-bromo-2-methylbutane and not 2-bromo-3-methylbutane.

[2]
f.

Deduce two features of this molecule that can be obtained from the mass spectrum. Use section 28 of the data booklet.

NIST Mass Spectrometry Data Center Collection © 2014 copyright by the U.S. Secretary of Commerce
on behalf of the United States of America. All rights reserved.

[2]
g(i).

Identify the bond responsible for the absorption at A in the infrared spectrum. Use section 26 of the data booklet.

NIST Mass Spectrometry Data Center Collection © 2014 copyright by the U.S. Secretary of Commerce
on behalf of the United States of America. All rights reserved.

 

[1]
g(ii).

Deduce the identity of the unknown compound using the previous information, the 1H NMR spectrum and section 27 of the data booklet.

SDBS, National Institute of Advanced Industrial Science and Technology (AIST).

[2]
g(iii).

Draw the stereoisomers of butan-2-ol using wedge-dash type representations.

[1]
h(i).

Outline how two enantiomers can be distinguished using a polarimeter.

[2]
h(ii).



Compound A is in equilibrium with compound B.

Predict the electron domain and molecular geometries around the oxygen atom of molecule A using VSEPR

 

[2]
a.

State the type of hybridization shown by the central carbon atom in molecule B.

[1]
b.

State the number of sigma (σ) and pi (π) bonds around the central carbon atom in molecule B.

[1]
c.

The IR spectrum of one of the compounds is shown:

COBLENTZ SOCIETY. Collection © 2018 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

Deduce, giving a reason, the compound producing this spectrum.

[1]
d.

Compound A and B are isomers. Draw two other structural isomers with the formula C3H6O.

[2]
e.

The equilibrium constant, Kc, for the conversion of A to B is 1.0×108 in water at 298K.

Deduce, giving a reason, which compound, A or B, is present in greater concentration when equilibrium is reached.

[1]
f(i).

Calculate the standard Gibbs free energy change, G, in kJmol1, for the reaction (A to B) at 298K. Use sections 1 and 2 of the data booklet.

[1]
f(ii).

Propanone can be synthesized in two steps from propene. Suggest the synthetic route including all the necessary reactants and steps.

[3]
g(i).

Propanone can be synthesized in two steps from propene.

Suggest why propanal is a minor product obtained from the synthetic route in (g)(i).

[2]
g(ii).



Phenylethene can be polymerized to form polyphenylethene (polystyrene, PS).

The major product of the reaction with hydrogen bromide is C6H5–CHBr–CH3 and the minor product is C6H5–CH2–CH2Br.

Draw the repeating unit of polyphenylethene.

[1]
a.

Phenylethene is manufactured from benzene and ethene in a two-stage process. The overall reaction can be represented as follows with ΔGθ = +10.0 kJ mol−1 at 298 K.

Calculate the equilibrium constant for the overall conversion at 298 K, using section 1 of the data booklet.

[2]
b.

The benzene ring of phenylethene reacts with the nitronium ion, NO2+, and the C=C double bond reacts with hydrogen bromide, HBr.

Compare and contrast these two reactions in terms of their reaction mechanisms.

 

Similarity: 

Difference:

[2]
c.

Outline why the major product, C6H5–CHBr–CH3, can exist in two forms and state the relationship between these forms.

 

Two forms: 

Relationship:

[2]
d(i).

The minor product, C6H5–CH2–CH2Br, can exist in different conformational forms (isomers).

Outline what this means.

[1]
d(ii).

The minor product, C6H5–CH2–CH2Br, can be directly converted to an intermediate compound, X, which can then be directly converted to the acid C6H5–CH2–COOH.

C6H5–CH2–CH2Br → X → C6H5–CH2–COOH

Identify X.

[1]
e.



Hybridization of hydrocarbons affects their reactivity.

Experiments were carried out to investigate the mechanism of reaction between 2-chloropentane and aqueous sodium hydroxide.

Distinguish between a sigma and pi bond.

[2]
a(i).

Identify the hybridization of carbon in ethane, ethene and ethyne.

[1]
a(ii).

State, giving a reason, if but-1-ene exhibits cis-trans isomerism.

[1]
b(i).

State the type of reaction which occurs between but-1-ene and hydrogen iodide at room temperature.

[1]
b(ii).

Explain the mechanism of the reaction between but-1-ene with hydrogen iodide, using curly arrows to represent the movement of electron pairs.

[4]
b(iii).

State, giving a reason, if the product of this reaction exhibits stereoisomerism.

[1]
b(iv).

Deduce the rate expression for this reaction.

[1]
c(i).

Deduce the units of the rate constant.

[1]
c(ii).

Determine the initial rate of reaction in experiment 4.

[2]
c(iii).

Deduce, with a reason, the mechanism of the reaction between 2-chloropentane and sodium hydroxide.

[1]
d.

Discuss the reason benzene is more reactive with an electrophile than a nucleophile.

[2]
e.