Naming Alkanes and Cycloalkanes

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Questions and Answers

What is the ending for all of the names of alkanes according to IUPAC nomenclature?

-yne

-ide

-ene

-ane (correct)

What is obtained when a hydrogen atom is removed from an alkane?

A carboxyl group

An alkyl group (correct)

An alkene

An alkyne

How do the names of unbranched alkyl groups end?

-ide

-ane

-yl (correct)

-ene

What determines the parent name for a branched-chain alkane?

The number of carbon atoms in the longest continuous chain Signup and view all the answers

What is the first step in naming a branched-chain alkane?

Locate the longest continuous chain of carbon atoms Signup and view all the answers

Why is IUPAC nomenclature used in chemistry?

To make naming compounds more systematic Signup and view all the answers

What type of compound is obtained when a hydrogen atom is removed from a branched-chain alkane?

A branched-chain alkyl group Signup and view all the answers

What is the name of the group that updates and develops the IUPAC nomenclature?

International Union of Pure and Applied Chemistry Signup and view all the answers

When numbering the carbons in a cycloalkane ring with two or more substituents, what should be the starting point?

The carbon with the substituent that is first in alphabetical order Signup and view all the answers

When naming a cycloalkane with three or more substituents, what is the priority in numbering the carbons?

The substituent that leads to the lowest set of numbers Signup and view all the answers

In what order should the substituents be listed in the name of a cycloalkane?

In alphabetical order Signup and view all the answers

What is the correct name for a compound that has a single ring system attached to a single chain with a greater number of carbon atoms?

Cycloalkylalkane Signup and view all the answers

How do the IUPAC rules for naming alkenes differ from those for naming alkanes?

The parent name is determined by the longest chain that contains the double bond Signup and view all the answers

What is the suffix used to form the name of an alkene?

-ene Signup and view all the answers

When naming a cycloalkane, what determines the direction of numbering the carbons in the ring?

The direction that gives the next substituent the lowest number possible Signup and view all the answers

What is the propyl group derived from?

Removal of a terminal hydrogen from propane Signup and view all the answers

What is the correct terminology for a compound that has a single ring system attached to a single chain with a greater number of carbon atoms?

Cycloalkylalkane Signup and view all the answers

What is the 1-methylethyl or isopropyl group derived from?

Removal of a hydrogen from the central carbon of propane Signup and view all the answers

How are cycloalkanes with one ring and no substituents named?

By adding the prefix 'cyclo' to the parent name Signup and view all the answers

What is the name of the cycloalkane with five carbon atoms in the ring?

Cyclopentane Signup and view all the answers

How are cycloalkanes with one ring and one substituent named?

By adding the name of the substituent to the beginning of the parent name Signup and view all the answers

What is the name of the cycloalkane with a cyclohexane ring and an attached isopropyl group?

Isopropylcyclohexane Signup and view all the answers

Is it necessary to specify a number (locant) for the carbon bearing the substituent in cycloalkanes with one ring and one substituent?

No, it is not necessary Signup and view all the answers

What is the general rule for naming cycloalkanes?

Add 'cyclo' to the beginning of the parent name Signup and view all the answers

What is the term used to describe identical or substantial groups on the same side of a double bond?

cis Signup and view all the answers

How are unbranched alkynes named?

By replacing the -ane of the name of the corresponding alkene with the ending -yne Signup and view all the answers

How is the chain numbered in the case of alkynes?

To give the carbon atoms of the triple bond the lower possible numbers Signup and view all the answers

What determines the direction of numbering when double and triple bonds are present?

The direction that gives the lowest overall set of locants Signup and view all the answers

What is the term used to describe identical or substantial groups on opposite sides of a double bond?

trans Signup and view all the answers

How are the bond-line formulas for alkenes written?

By representing the carbon atoms with a bond Signup and view all the answers

What is the purpose of the locants in IUPAC nomenclature?

To give the lowest overall set of numbers to the carbon atoms of multiple bonds Signup and view all the answers

What is the term used to describe a combination of double and triple bonds in a molecule?

Polyyne Signup and view all the answers

What is the parent name of an alkene with a longest chain containing six carbon atoms?

Hexene Signup and view all the answers

When numbering the chain, where should you begin?

At the end of the chain nearer the double bond Signup and view all the answers

How do you designate the location of the double bond?

Using the number of the first atom of the double bond as a prefix Signup and view all the answers

How do you indicate the locations of substituent groups?

By using the numbers of the carbon atoms to which they are attached Signup and view all the answers

What is the rule for numbering substituted cycloalkenes?

Numbering the carbon atoms of the double bond as the first and second Signup and view all the answers

Why is it not necessary to specify the position of the double bond in substituted cycloalkenes?

Because it will always begin with C1 and C2 Signup and view all the answers

What is the purpose of numbering the chain in alkenes?

To determine the location of the double bond and substituent groups Signup and view all the answers

What is the format of the locant for the alkene suffix?

It must be placed immediately before the suffix Signup and view all the answers

Study Notes

How to Name Alkanes

The ending for all names of alkanes is -ane.
The longest continuous chain of carbon atoms determines the parent name for the alkane.

Branched Alkyl Groups

Branched alkyl groups are derived from propane by removing a hydrogen atom from the central carbon.
Examples include the propyl group and the 1-methylethyl (isopropyl) group.

How to Name Monocyclic Cycloalkanes

Cycloalkanes are named by adding "cyclo" before the parent name.
The number of carbon atoms in the ring is counted, and "cyclo" is added to the beginning of the name of the alkane with that number of carbons.
For example, cyclopropane has three carbons, and cyclopentane has five carbons.

Cycloalkanes with One Ring and One Substituent

The name of the substituent is added to the beginning of the parent name.
For example, cyclohexane with an attached isopropyl group is isopropylcyclohexane.

Cycloalkanes with One Ring and Two or More Substituents

The carbons in the ring are numbered starting at the carbon with the substituent that is first in the alphabet.
The direction of numbering is chosen to give the next substituent the lower number possible.
When there are three or more substituents, begin at the substituent that leads to the lowest set of numbers (locants).

Cycloalkanes with Multiple Rings

When a single ring system is attached to a single chain with a greater number of carbon atoms, or when more than one ring system is attached to a single chain, the compounds are named as cycloalkylalkanes.

How to Name Alkenes and Cycloalkenes

The IUPAC rules for naming alkenes are similar to those for naming alkanes.
The parent name is determined by selecting the longest chain that contains the double bond and changing the ending of the name of the alkane of identical length from –ane to -ene.
The chain is numbered to include both carbon atoms of the double bond and begin numbering at the end of the chain nearer the double bond.

How to Name Alkynes

Alkynes are named in much the same way as alkenes.
Unbranched alkynes are named by replacing the -ane of the name of the corresponding alkane with the ending -yne.
The chain is numbered to give the carbon atoms of the triple bond the lower possible numbers.

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Description

Learn how to name alkanes and cycloalkanes, including the rules for branched alkyl groups and monocyclic cycloalkanes. Understand the longest continuous chain rule and the importance of the parent name.