Organic Chemistry : Identifying Amino Compounds

Study concepts, example questions & explanations for Organic Chemistry

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Example Questions

Example Question #1 : Identifying Amino Compounds

Ephedrine (shown below) contains what type of amine?

Mcat_problem_set_1

Possible Answers:

Primary

Secondary

Quaternary

Tertiary

Neutral

Correct answer:

Secondary

Explanation:

A secondary amine is an amine (nitrogen atom) that is attached to two carbon-containing groups (alkyl groups or aryl groups). The nitrogen in ephedrine is attached to two alkyl groups, making it a secondary amine.

Primary amines are generally written as . Secondary amines are generally written as . A tertiary amine will be bound to three different R-groups. Quaternary amines require a positive charge on the nitrogen atom to accommodate a fourth R-group.

Example Question #31 : Organic Functional Groups And Molecules

The amino functional group in the given molecule is best described as a __________.

Q9

Possible Answers:

Achiral tertiary amine

Chiral tertriary amine

Chiral secondary amine

Chiral tertiary amine

Achiral secondary amine

Correct answer:

Chiral tertiary amine

Explanation:

An amino group is a nitrogen-containing functional group, and is the part pictured on the right of the given molecule. This amine has three substituents: the alkyl ketone, the methyl, and the ethyl. Hydrogens do not count as "substituents." Any amine with three substituents is considered a "tertiary" amine.

This amine is chiral because it has four different substitutions at the nitrogen atom, which is the definition of chirality. 

Note: "tetriary" is not a real term in organic chemistry.

 

Example Question #39 : Organic Functional Groups

Which of these is a tertiary amine?

Possible Answers:

None of the other answers

Aniline

Ammonia

Trimethylamine

Piperidine

Correct answer:

Trimethylamine

Explanation:

A tertiary amine has three organic groups bonded to it. Triethylamine has three ethyl groups bonded to it, so that is the correct answer. Ammonia is so it has no organic groups attached. Piperidine is a six-membered ring with a nitrogen as one of the members, making it a secondary amine. Aniline is a benzene ring with a  bonded to it, so it is a primary amine.

Example Question #131 : Organic Concepts

Which of the following molecules is an amine?

A)

Aldehyde

B)

Amide

C)

Amine

D)

Carboxylic acid

Possible Answers:

B

D

A

C

None of these

Correct answer:

C

Explanation:

C is the correct answer.

Amine

The molecule pictured above is an anime because it contains a nitrogen group bonded to two hydrogen atoms and one R-group. A shows an aldehyde, B shows an amide, and D shows a carboxylic acid.

Example Question #132 : Organic Concepts

Which of the following is the most accurate characteristic of ammonia?

Possible Answers:

It is a Lewis base

It is a Lewis acid

It has two lone pairs of electrons

It is an electrophile

Correct answer:

It is a Lewis base

Explanation:

For this question, we're being asked to identify a characteristic of ammonia.

First, we need to remember what ammonia is. Ammonia is a molecule that consists of a nitrogen atom bonded to three separate hydrogen atoms. In doing so, these three bonds contribute to six of the valence shell electrons for nitrogen. The remaining two valence electrons exists on the nitrogen atom as a lone pair. Thus, there is only one lone pair of electrons (pair being two).

Also, the lone pair of electrons on ammonia allows it to act as a Lewis base by donating them (not a Lewis acid, which accepts electrons). Furthermore, this tendency for ammonia to donate its electrons would make it a nucleophile, not an electrophile.

Example Question #1 : Identifying Amino Compounds

The molecule guanosine, as shown below, is an important nucleoside found in biological systems. When combined with phosphate groups, guanosine acts as a vital constituent of nucleic acids. Based on the structure of this compound, how many amide groups are there in this molecule?

 Guanosine

Possible Answers:

Correct answer:

Explanation:

In this question, we're shown the structure of the nucleoside called guanosine. We're asked to determine how many amide functional groups exist in this molecule.

First, to answer this question, we need to know what an amide functional group is. Amides consist of a carbon atom double bonded to an oxygen atom, and single bonded to a nitrogen atom. Note that this is distinct from the similarly named amine functional group, which contains a nitrogen atom with a lone pair of electrons and single bonded to three other atoms, which can be hydrogen or "R-groups" containing carbon atoms.

When looking at the molecular structure of guanosine, we can see that there is only a single amide group.

Guanosine answer

Example Question #2 : Identifying Amino Compounds

What is the IUPAC name for the compound shown?

Img 1326

Possible Answers:

3-propanamine

1-propanamine

1-aminopropane

propanamine

Correct answer:

1-propanamine

Explanation:

The molecule's longest carbon chain has 3 carbons (thus, "prop"), and the lack of double bonds makes it an alkANe (thus "propan-"). The only functional group on this molecule is the amino group (thus "propanamine"), located on carbon number 1 if read from right to left, or carbon number 3 if read from left to right. The IUPAC rules state that the correct name for a molecule numbers the carbon chain such that functional groups get the lowest numbers possible. Thus "1-propanamine."

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