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Date	May 2018	Marks available	2	Reference code	18M.2.hl.TZ1.3
Level	HL	Paper	2	Time zone	TZ1
Command term	State	Question number	3	Adapted from	N/A

Question

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]

Under certain conditions, ethyne can be converted to benzene.

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

3C₂H₂(g) → C₆H₆(g)

[2]

c.i.

Determine the standard enthalpy change, ΔH^Θ, for the following similar reaction, using ΔH_f 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, ΔS^Θ, 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]

Markscheme

nickel/Ni «catalyst»

high pressure

heat

Accept these other catalysts: Pt, Pd, Ir, Rh, Co, Ti.

Accept “high temperature” or a stated temperature such as “150 °C”.

[2 marks]

a.i.

M18/4/CHEMI/HP2/ENG/TZ1/03.a.ii/M

Ignore square brackets and “n”.

Connecting line at end of carbons must be shown.

[1 mark]

a.ii.

ethyne: C₂H₂ + Cl₂ → CHClCHCl

benzene: C₆H₆ + Cl₂ → C₆H₅Cl + HCl

Accept “C₂H₂Cl₂”.

[2 marks]

ΔH^Θ = bonds broken – bonds formed

«ΔH^Θ = 3(C≡C) – 6(CC)_benzene / 3 $\times$ 839 – 6 $\times$ 507 / 2517 – 3042 =» –525 «kJ»

Award [2] for correct final answer.

Award [1 max] for “+525 «kJ»”.

Award [1 max] for:

«ΔH^Θ = 3(C≡C) – 3(C–C) – 3(C=C) / 3 $\times$ 839 – 3 $\times$ 346 – 3 $\times$ 614 / 2517 – 2880 =» –363 «kJ».

[2 marks]

c.i.

ΔH^Θ = ΣΔH_f (products) – ΣΔH_f (reactants)

«ΔH^Θ = 49 kJ – 3 $\times$ 228 kJ =» –635 «kJ»

Award [2] for correct final answer.

Award [1 max] for “+635 «kJ»”.

[2 marks]

c.ii.

ΔH_f values are specific to the compound

bond enthalpy values are averages «from many different compounds»

condensation from gas to liquid is exothermic

Accept “benzene is in two different states «one liquid the other gas»” for M2.

[2 marks]

c.iii.

«ΔS^Θ = 173 – 3 $\times$ 201 =» –430 «J K^–1»

[1 mark]

c.iv.

T = «25 + 273 =» 298 «K»

ΔG^ϴ «= –635 kJ – 298 K × (–0.430 kJ K^–1)» = –507 kJ

ΔG^ϴ < 0 AND spontaneous

ΔG^ϴ< 0 may be inferred from the calculation.

[3 marks]

c.v.

equal C–C bond «lengths/strengths»

regular hexagon

«all» C–C have bond order of 1.5

«all» C–C intermediate between single and double bonds

Accept “all C–C–C bond angles are equal”.

[1 mark]

Examiners report

[N/A]

a.i.

[N/A]

a.ii.

[N/A]

c.i.

[N/A]

c.ii.

[N/A]

c.iii.

[N/A]

c.iv.

[N/A]

c.v.

[N/A]

Syllabus sections

Core » Topic 10: Organic chemistry » 10.2 Functional group chemistry

Show 137 related questions

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Outline the formation of polyethene from ethene by drawing three repeating units of the polymer.
18M.2.sl.TZ1.3d:
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22M.2.hl.TZ1.5c:
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22M.1.sl.TZ1.26:
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22M.2.sl.TZ1.3e:
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22M.1.hl.TZ1.34:
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A. Reflux with acidified potassium dichromate (VI)

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C. Distil with acidified potassium dichromate (VI)

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17M.3.hl.TZ2.3c.ii:
Suggest, giving one reason, whether this is an addition or condensation reaction.
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18M.2.sl.TZ2.7b.ii:
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Outline how the experimental procedures differ for the synthesis of the aldehyde and the carboxylic acid.
18M.1.hl.TZ2.35: Which is the correct combination of substitution reaction mechanisms?
22M.1.hl.TZ2.35:
Which reaction involves homolytic fission?

A. CH₄ + Cl₂

B. CH₃Br + NaOH

C. (CH₃)₃CBr + NaOH

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18M.1.hl.TZ1.33: Which monomer could create this polymer? A. But-2-ene B. But-1-ene C. ...
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22M.2.sl.TZ2.4d(ii):
Write the equation for the reaction between but-2-ene and hydrogen bromide.
22M.2.sl.TZ2.4d(iii):
State the type of reaction.
17M.2.sl.TZ1.5d:
Chloroethene, C₂H₃Cl, can undergo polymerization. Draw a section of the polymer with three repeating units.
17M.1.sl.TZ2.25: Which describes the reaction between a halogen and ethane?
17M.2.hl.TZ2.6b:
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.
19M.1.hl.TZ2.35:
What must be present on a nucleophile?

A. Negative charge

B. Lone pair of electrons

C. Positive charge

D. Symmetrical distribution of electrons
19M.1.sl.TZ1.27:
Which alcohol would produce a carboxylic acid when heated with acidified potassium dichromate(VI)?

A. propan-2-ol

B. butan-1-ol

C. 2-methylpropan-2-ol

D. pentan-3-ol
19N.1.sl.TZ0.26: What type of reaction occurs when C6H13Br becomes C6H13OH? A. Nucleophilic...
18M.1.hl.TZ1.40: Which would be the most effective method to distinguish between liquid propan-1-ol and...
18M.2.hl.TZ1.3a.ii:
Outline the formation of polyethene from ethene by drawing three repeating units of the polymer.
20N.2.hl.TZ0.1d(i):
State the type of reaction occurring when ethane reacts with chlorine to produce chloroethane.
22M.2.hl.TZ2.8d(iii): State the type of reaction.
22M.2.hl.TZ2.8d(ii):
Write the equation for the reaction between but-2-ene and hydrogen bromide.
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18N.1.sl.TZ0.27:
Which compounds react to form CH₃CH₂CH₂COOCH(CH₃)₂?

A. propanoic acid and propan-2-ol

B. propanoic acid and butan-2-ol

C. butanoic acid and propan-1-ol

D. butanoic acid and propan-2-ol
18N.2.sl.TZ0.2d.i:
State a suitable oxidizing agent for the oxidation of propan-2-ol in an acidified aqueous solution.
18N.2.sl.TZ0.2d.iii:
Deduce the product of the oxidation of propan-2-ol with the oxidizing agent in (d)(i).
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18N.2.hl.TZ0.9a: State a reason why most halogenoalkanes are more reactive than alkanes.
18N.2.sl.TZ0.7a: Identify the type of reaction in step 1.
19M.2.sl.TZ1.1c(i):
Identify the initiation step of the reaction and its conditions.
17M.3.hl.TZ1.9a:
Deduce the repeating unit of the polymer and the other product of the reaction.
18M.2.sl.TZ2.7b.i:
Formulate the ionic equation for the oxidation of propan-1-ol to the corresponding aldehyde by acidified dichromate(VI) ions. Use section 24 of the data booklet.
19N.2.sl.TZ0.3b:
Write an equation for the reaction of C₂H₅Cl with aqueous sodium hydroxide to produce a C₂H₆O compound, showing structural formulas.
19M.1.hl.TZ1.34:
Which alcohol would produce a carboxylic acid when heated with acidified potassium dichromate(VI)?

A. propan-2-ol

B. butan-1-ol

C. 2-methylpropan-2-ol

D. pentan-3-ol
16N.2.sl.TZ0.5b:
Both propane and propene react with bromine.

(i) State an equation and the condition required for the reaction of 1 mol of propane with 1 mol of bromine.

(ii) State an equation for the reaction of 1 mol of propene with 1 mol of bromine.

(iii) State the type of each reaction with bromine.

Propane:

Propene:
16N.2.sl.TZ0.1d:
Ethane-1,2-diol can be oxidized first to ethanedioic acid, (COOH)₂, and then to carbon dioxide and water. Suggest the reagents to oxidize ethane-1,2-diol.
18N.1.sl.TZ0.24:
Which compounds cause the colour of acidified potassium manganate(VII) solution to change from purple to colourless?

I. CH₃CH₂CH₂CH₂OH

II. (CH₃)₃CCH₂OH

III. CH₃CH₂CH(OH)CH₃

A. I and II only

B. I and III only

C. II and III only

D. I, II and III
19M.2.hl.TZ2.1c(i):
State the name of product B, applying IUPAC rules.
19M.1.sl.TZ1.26: What is the mechanism of the reaction between alkenes and halogens in the absence of...
19M.1.sl.TZ2.26:
Methane reacts with chlorine in sunlight.

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

Which type of reaction occurs?

A. free-radical substitution

B. electrophilic substitution

C. nucleophilic substitution

D. electrophilic addition
18M.2.hl.TZ1.7c.i:
State the organic product of the reaction between 1-chlorobutane, CH₃CH₂CH₂CH₂Cl, and aqueous sodium hydroxide.
19M.1.sl.TZ2.25: Which of the following can be both formed from bromoethane and converted directly into...
19M.2.hl.TZ2.1a:
Write an equation for the complete combustion of ethyne.
22M.1.sl.TZ2.25:
Which structure represents a repeating unit of a polymer formed from propene?

A. –CH₂–CH(CH₃)–

B. –CH₂–CH₂–CH₂–

C. –CH(CH₃)–CH(CH₃)–

D. –CH₂–CH₂–
17N.2.sl.TZ0.6a.i:
Deduce the type of chemical reaction and the reagents used to distinguish between these compounds.
17M.1.hl.TZ1.35: What is the major product of the reaction between 2-methylbut-2-ene and hydrogen bromide? A....
17N.1.sl.TZ0.27: Which type of reaction occurs between an alcohol and a carboxylic acid? A. Addition B....
16N.1.sl.TZ0.26: Which type of reaction occurs when methanol and propanoic acid react together in the presence...
16N.1.sl.TZ0.25:
Which monomer is used to form the polymer with the following repeating unit?

A. CH₃CH=CHCH₃

B. CH₃CH₂CH=CH₂

C. CH₃CH₂CH₂CH₃

D. (CH₃)₂C=CH₂
16N.3.sl.TZ0.2b: In trial 3, the students noticed that after heating, the crucible had turned black on the...
19M.2.sl.TZ1.1c(ii):
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.
17N.1.sl.TZ0.25:
Which compound can be oxidized when heated with an acidified solution of potassium dichromate(VI)?

A. CH₃C(O)CH₂CH₃

B. CH₃CH₂CH(OH)CH₃

C. (CH₃)₃COH

D. CH₃(CH₂)₂COOH
17N.3.sl.TZ0.8b.i: State the type of reaction occurring during the titration.
17N.2.sl.TZ0.6b:
Explain, with the help of equations, the mechanism of the free-radical substitution reaction of ethane with bromine in presence of sunlight.
17N.1.sl.TZ0.24: What is the major product of the reaction between HCl and but-2-ene? A....
19M.2.hl.TZ1.1d(i):
Identify the initiation step of the reaction and its conditions.
19N.3.sl.TZ0.9d(i): State one similarity and one difference in composition between phospholipids and...
19N.2.sl.TZ0.3a: State the type of reaction which converts ethene into C2H5Cl.
19N.3.hl.TZ0.12c: State one similarity and one difference in composition between phospholipids and...
18M.1.sl.TZ1.27:
Which compound could be formed when CH₃CH₂CH₂OH is heated with acidified potassium dichromate(VI)?

I. CH₃CH₂CHO

II. CH₃CH₂COOH

III. CH₃COCH₃

A. I and II only

B. I and III only

C. II and III only

D. I, II and III
21N.2.sl.TZ0.4a(i): Identify the type of reaction.
19N.2.hl.TZ0.3a(i): State the type of reaction.
19N.2.hl.TZ0.3c(i):
Write an equation for the complete combustion of the compound C₃H₈O formed in (a)(iv).
19N.2.hl.TZ0.3e: Propene is often polymerized. Draw a section of the resulting polymer, showing two repeating...
17M.2.hl.TZ2.7b.ii:
Deduce the structural formula of the main organic product when hex-1-ene reacts with hydrogen bromide.
19N.3.hl.TZ0.5a:
Draw the structure of the monomers of Kevlar^® if the by-product of the condensation polymerization is hydrogen chloride.
19N.3.sl.TZ0.14a:
Write the equation for the complete combustion of ethanol.
17M.2.sl.TZ1.6b:
State the typical reactions that benzene and cyclohexene undergo with bromine.
17M.2.sl.TZ1.6a:
Discuss the physical evidence for the structure of benzene.
18M.2.hl.TZ1.3b:
Ethyne reacts with chlorine in a similar way to ethene. Formulate equations for the following reactions.
18M.2.sl.TZ1.3a.i:
Ethyne, like ethene, undergoes hydrogenation to form ethane. State the conditions required.
19M.1.hl.TZ2.33:
Methane reacts with chlorine in sunlight.

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

Which type of reaction occurs?

A. free-radical substitution

B. electrophilic substitution

C. nucleophilic substitution

D. electrophilic addition
21M.2.hl.TZ1.5e(iv): Propan-2-ol can also be formed in one step from a compound containing a carbonyl...
17M.2.hl.TZ2.7b.i:
Bromine was added to hexane, hex-1-ene and benzene. Identify the compound(s) which will react with bromine in a well-lit laboratory.
19M.2.sl.TZ2.1a:
Write an equation for the complete combustion of ethyne.
17M.2.sl.TZ2.6c:
Polyvinyl chloride (PVC) is a polymer with the following structure.

State the structural formula for the monomer of PVC.
17M.2.sl.TZ1.5a:
Ethane, C₂H₆, reacts with chlorine in sunlight. State the type of this reaction and the name of the mechanism by which it occurs.
17M.2.sl.TZ2.6b:
Bromine was added to hexane, hex-1-ene and benzene. Identify the compound(s) which will react with bromine in a well-lit laboratory.
19N.2.hl.TZ0.3d(i):
State the reagents for the conversion of the compound C₃H₈O formed in (a)(iv) into C₃H₆O.
19N.1.sl.TZ0.28: Which compound cannot undergo addition polymerization?
19N.1.sl.TZ0.27: Which will react with a halogen by an electrophilic substitution mechanism?
19N.3.sl.TZ0.9b: State one impact on health of the increase in LDL cholesterol concentration in blood.
19M.2.hl.TZ2.6a:
Draw the repeating unit of polyphenylethene.
20N.1.sl.TZ0.25: Which molecule will decolorize bromine water in the dark? A. cyclohexane B. hexane C. ...
20N.1.sl.TZ0.27: Which mechanism does benzene most readily undergo? A. Nucleophilic substitution B. ...
17M.2.hl.TZ2.2a.v:
Identify one organic functional group that can react with acidified K₂Cr₂O₇(aq).
22M.2.sl.TZ1.3d(ii): Deduce the structural formula of the repeating unit of the polymer formed from this alkene.
19M.2.sl.TZ2.1c(i):
Product A contains a carbon–carbon double bond. State the type of reactions that compounds containing this bond are likely to undergo.
19M.2.hl.TZ1.2f(ii):
Formulate the equation for the complete combustion of benzoic acid in oxygen using only integer coefficients.
19N.2.sl.TZ0.3d(i):
State the reagents and conditions for the conversion of the compound C₂H₆O, produced in (b), into C₂H₄O.
19M.2.hl.TZ1.1d(ii):
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.
19N.3.hl.TZ0.24c:
Explain how redox chemistry is used to measure the ethanol concentration in a breathalyser.
21M.1.sl.TZ1.26: What is formed in a propagation step of the substitution reaction between bromine and...
21M.1.sl.TZ1.27:
Which monomer would produce the polymer shown?

A. ${CF}_{3} {CCl}_{2} F$

B. ${CF}_{3} CClHF$

C. ${CF}_{2} CClF$

D. ${CF}_{2} {CF}_{2}$
21M.2.hl.TZ1.5d: A white solid was formed when ethene was subjected to high pressure. Deduce the type of...
21M.2.hl.TZ1.5c: Suggest two possible products of the incomplete combustion of ethene that would not be formed...
21M.2.hl.TZ1.5e(iii): 2-bromopropane can be converted directly to propan-2-ol. Identify the reagent required.
21M.1.sl.TZ2.26:
Which monomer forms the polymer shown?

A. ${CH(Cl)=CH(CH}_{3})$

B. ${CH}_{2} {=C(Cl)CH}_{3}$

C. ${(CH}_{3})_{2} CHCl$

D. ${CH}_{2} =CHCl$
19M.2.sl.TZ1.2b(ii):
Formulate the equation for the complete combustion of benzoic acid in oxygen using only integer coefficients.
19M.2.hl.TZ2.1d(i):
Suggest the reagents and conditions required to ensure a good yield of product B.

Reagents:

Conditions:
20N.2.sl.TZ0.1d(iii):
Write the equation for the reaction of chloroethane with a dilute aqueous solution of sodium hydroxide.
21M.1.hl.TZ2.37:
Which can be reduced to a secondary alcohol?

A. C₂H₅COOH

B. CH₃CH₂OCH₃

C. (CH₃)₂CHCHO

D. CH₃COC₂H₅
17M.2.sl.TZ1.5b:
Formulate equations for the two propagation steps and one termination step in the formation of chloroethane from ethane.
17N.2.sl.TZ0.6a.ii:
State the observation expected for each reaction giving your reasons.
21M.2.sl.TZ1.5d: A white solid was formed when ethene was subjected to high pressure. Deduce the type of...
21M.2.sl.TZ1.5c: Suggest two possible products of the incomplete combustion of ethene that would not be formed...
21M.2.sl.TZ2.4a:
Several compounds can be synthesized from but-2-ene. Draw the structure of the final product for each of the following chemical reactions.
21M.2.sl.TZ2.4d:
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.
21M.2.hl.TZ2.4a:
Several compounds can be synthesized from but-2-ene. Draw the structure of the final product for each of the following chemical reactions.
21M.2.hl.TZ2.5c:
Write the equation and name the organic product when ethanol reacts with methanoic acid.
21M.2.hl.TZ2.5b:
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.
17M.2.sl.TZ2.6a:
Using relevant equations, show the initiation and the propagation steps for this reaction.
20N.2.sl.TZ0.1d(iv):
Deduce the nucleophile for the reaction in d(iii).
20N.2.sl.TZ0.1d(i):
State the type of reaction occurring when ethane reacts with chlorine to produce chloroethane.
20N.2.hl.TZ0.1d(ii):
Predict, giving a reason, whether ethane or chloroethane is more reactive.
20N.2.sl.TZ0.1d(ii):
Predict, giving a reason, whether ethane or chloroethane is more reactive.
22M.2.hl.TZ2.8c:
Describe a test and the expected result to indicate the presence of carbon–carbon double bonds.
22M.2.sl.TZ2.4c:
Describe a test and the expected result to indicate the presence of carbon–carbon double bonds.
21M.1.sl.TZ2.27:
Which is a propagation step in the free-radical substitution mechanism of ethane with chlorine?

A. C $l$ ₂ → 2 •C $l$

B. •C₂H₅ + C $l$ ₂ → C₂H₅C $l$ + •C $l$

C. •C₂H₅ + •C $l$ → C₂H₅C $l$

D. C₂H₆ + •C $l$ → C₂H₅C $l$ + •H
22M.2.hl.TZ1.5d(i): Identify the type of reaction.
20N.1.hl.TZ0.34:
Which molecule can be oxidized to a carboxylic acid by acidified potassium dichromate(VI)?

A. Propan-1-ol

B. Propan-2-ol

C. 2-methylpropan-2-ol

D. Propanone
22M.1.sl.TZ2.22:
Which combination best describes what is happening to chloromethane, CH₃Cl, in the equation below?

CH₃Cl (g) + H₂(g) $⇌$ CH₄(g) + HCl (g)

A. Oxidation and addition

B. Oxidation and substitution

C. Reduction and addition

D. Reduction and substitution
21N.2.sl.TZ0.4a(ii): Outline the role of the hydroxide ion in this reaction.
21N.2.hl.TZ0.10b(ii): State the type of reaction which occurs between but-1-ene and hydrogen iodide at room...
21N.2.sl.TZ0.7b: Formulate equations for the two propagation steps and one termination step in the formation...

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Core » Topic 10: Organic chemistry

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