IUPAC Naming of Organic Compounds

You're viewing free preview questions — 4 questions previewing here — subscribe to unlock 262 more, plus the Full Question Bank, Mock Papers & Worksheets.Upgrade

IUPAC Naming of Organic Compounds — Free MYP5 Chemistry Practice Questions

1QuestionMultiple substituents (di, tri, tetra…)Concept Practice

2 marks~3 minCriterion A

The structural formula below shows a straight-chain alkane with four carbon atoms. A methyl group (

\text{CH}_3

) is attached to carbon-2 and another methyl group is attached to carbon-3. Each carbon satisfies tetravalency.

(a) Deduce the IUPAC name of this compound. [2]

Solutions

2QuestionNaming cyclic compounds (basic)Assessment Practice

5 marks~8 minCriterion D

Three isomers of

\text{C}_8\text{H}_{16}

have the following experimentally measured boiling points:

1,1-dimethylcyclohexane: 119.7 °C
1,2-cis-dimethylcyclohexane: 129.7 °C
1,3-trans-dimethylcyclohexane: 124.5 °C

Draw the structural formula of each isomer using wedge-dash notation to show the position and stereochemistry of the methyl groups. [2]

Explain how the position of the methyl groups affects the symmetry and polarity of each isomer. [1]

Evaluate which isomer's structure best accounts for the observed order of boiling points, justifying your answer in terms of intermolecular forces. [2]

Solutions

3QuestionNaming cyclic compounds (basic)Assessment Practice

5 marks~8 minCriterion B

The standard enthalpy of combustion per

\text{CH}_2

group for four cycloalkanes is given below.

Cycloalkane	cyclopropane	cyclobutane	cyclopentane	cyclohexane
Enthalpy per $\text{CH}_2$ / kJ mol $^{-1}$	$-697$	$-683$	$-664$	$-659$

Identify the trend in combustion enthalpy per

\text{CH}_2

as ring size increases from cyclopropane to cyclohexane. [1]

Deduce the combustion enthalpy per

\text{CH}_2

for cycloheptane (

\text{C}_7\text{H}_{14}

), showing your reasoning from the data. [2]

Justify the trend identified in (a) using Baeyer strain theory, and explain why the values approach a limiting enthalpy as ring size increases. [2]

Solutions

4QuestionNaming compounds with functional groups like Alcohols (-ol) and Carboxylic acids (-oic acid)Assessment Practice

5 marks~8 minCriterion C

An unknown organic compound has the molecular formula

\text{C}_3\text{H}_6\text{O}_2

. Its infrared (IR) spectrum shows a strong, broad absorption at approximately

3300 \ \text{cm}^{-1}

and a strong, sharp absorption at approximately

1710 \ \text{cm}^{-1}

.

Two students propose different identities for the compound:

Student 1: "The compound is propan-1-ol."
Student 2: "The compound is propanoic acid."

Identify the functional groups responsible for each IR absorption band. [2]

State the IUPAC name and structural formula of the correct compound. [1]

Evaluate both students' claims, explaining why one is supported by the spectral data and the other is not. [2]

Solutions

Questions 5-266

Unlock these questions with Premium

That's every free question here — 4 of 266.

+262 more questions, plus Mock Papers & Worksheets, are waiting in Premium.

Upgrade