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Date	November 2021	Marks available	3	Reference code	21N.2.sl.TZ0.7
Level	SL	Paper	2	Time zone	TZ0
Command term	Formulate	Question number	7	Adapted from	N/A

Question

Alkanes undergo combustion and substitution.

Determine the molar enthalpy of combustion of an alkane if 8.75 × 10⁻⁴ moles are burned, raising the temperature of 20.0 g of water by 57.3 °C.

[2]

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

[3]

Markscheme

«q = mcΔT = 20.0 g × 4.18 J g⁻¹°C⁻¹ × 57.3 °C =» 4790 «J» ✔

« $∆ H_{c} \frac{4790 J}{\frac{1000}{8.75 \times 10^{- 4} mol}} =$ » –5470 «kJ mol^–1» ✔

Award [2] for correct final answer.

Accept answers in the range –5470 to –5480 «kJ mol⁻¹».

Accept correct answer in any units, e.g. –5.47 «MJ mol⁻¹» or 5.47 x 10⁶«J mol⁻¹».

Cl· + C₂H₆ → ·C₂H₅ + HCl ✔

·C₂H₅ + Cl₂ → Cl· + C₂H₅Cl ✔

·C₂H₅ + Cl· → C₂H₅Cl
OR
Cl· + Cl· → Cl₂
OR
·C₂H₅ + ·C₂H₅ → C₄H₁₀ ✔

Do not penalize incorrectly placed radical sign, eg C₂H₅·.

Examiners report

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Syllabus sections

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

Show 137 related questions

18M.1.sl.TZ1.25: What is the product of the reaction between hex-3-ene and steam? A. Hexan-1-ol B. ...
18M.1.sl.TZ1.26: Which of these reactions proceeds by a free radical mechanism in the presence of UV...
18M.2.sl.TZ1.3a.ii:
Outline the formation of polyethene from ethene by drawing three repeating units of the polymer.
18M.2.sl.TZ1.3d:
State the characteristic reaction mechanism of benzene.
18M.1.sl.TZ2.26: What is the mechanism for the reaction of propene with iodine in the dark? A. ...
22M.2.hl.TZ1.5b(iii): Deduce the structural formula of the repeating unit of the polymer formed from this alkene.
22M.2.hl.TZ1.5c:
Deduce what would be observed when Compound B is warmed with acidified aqueous potassium dichromate (VI).
22M.1.sl.TZ1.26:
Which reagents and conditions are best for converting propan-1-ol into propanoic acid?

A. Reflux with acidified potassium dichromate (VI)

B. Reflux with aqueous sodium hydroxide

C. Distil with acidified potassium dichromate (VI)

D. Distil with aqueous sodium hydroxide
22M.1.sl.TZ1.27: What is produced when chlorobutane is treated with aqueous sodium hydroxide solution? A. ...
22M.2.sl.TZ1.3f(i): Identify the type of reaction.
22M.2.sl.TZ1.3e:
Deduce what would be observed when Compound B is warmed with acidified aqueous potassium dichromate (VI).
19N.2.sl.TZ0.3e: Ethene is often polymerized. Draw a section of the resulting polymer, showing two repeating...
22M.1.hl.TZ1.34:
Which reagents and conditions are best for converting propan-1-ol into propanoic acid?

A. Reflux with acidified potassium dichromate (VI)

B. Reflux with LiAlH₄

C. Distil with acidified potassium dichromate (VI)

D. Distil with LiAlH₄
19N.2.sl.TZ0.3c(i):
Write an equation for the complete combustion of the organic product in (b).
17M.3.hl.TZ2.3c.ii:
Suggest, giving one reason, whether this is an addition or condensation reaction.
22M.1.sl.TZ2.27: Which reaction mechanisms are typical for alcohols and halogenoalkanes?
18M.2.sl.TZ2.7b.ii:
The aldehyde can be further oxidized to a carboxylic acid.

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

D. C₆H₆ + HNO₃ + H₂SO₄
18M.1.hl.TZ1.33: Which monomer could create this polymer? A. But-2-ene B. But-1-ene C. ...
17M.1.sl.TZ2.26: Which conditions are used to convert ethanol to ethanal? A. Excess oxidizing agent and...
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.
18M.2.hl.TZ1.3a.i:
Ethyne, like ethene, undergoes hydrogenation to form ethane. State the conditions required.
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.
16N.3.sl.TZ0.17b: Oseltamivir does not possess the carboxyl group needed for activity until it is chemically...
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).
18N.2.hl.TZ0.9b: Classify 1-bromopropane as a primary, secondary or tertiary halogenoalkane, giving a reason.
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...

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