organic chemistry Flashcards
Define an alkane.
An alkane is an organic molecule consisting of only hydrogen and carbon (hydrocarbon) connnected by single (sigma) bonds.
What is the generic formula for an alkane? Give the molecular formula for a nine carbon alkane.
The generic formula for an alkane is CnH2n+2. A nine carbon alkane has the formula: C9H20.
Define a (mono) cyclic alkane.
A (mono) cyclic alkane is a hydrocarbon with one ring structure. All the carbons and hydrogens are covalently joined by single (sigma) bonds.
Provide the generic formula for a (mono) cyclic alkane. Give the formula for a seven carbon (mono) cyclic alkane.
The generic formula of a (mono) cyclic alkane is CnH2n. The formula for a seven carbon (mono) cyclic alkane is C7H14.
Define alkene.
An alkene is an organic molecule consisting of only hydrogen and carbon (hydrocarbon) connnected by single (sigma) bonds and one carbon to carbon double bond.
If there is more than one double bond, then technically this is not an alkene. For instance if there are two double bonds then the molecule is referred to as an alkadiene.
Provide the generic formula for an alkene. Give the formula for a five carbon alkene.
The generic formula of an alkene is CnH2n. The formula for a five carbon alkene is C5H10.
Define alkyne.
An alkyne is an organic molecule consisting of only hydrogen and carbon (hydrocarbon) connnected by single (sigma) bonds and one carbon to carbon triple bond.
If there is more than one triple bond, then technically this is not an alkyne. For instance, if there are two triple bonds then the molecule is referred to as an alkadiyne.
Provide the generic formula for an alkyne. Give the formula for a six carbon alkyne.
The generic formula of an alkyne is CnH2n-2. The formula for a five carbon alkene is C<span>6</span>H10.
Give the formula for a 10 carbon (mono) cyclic alkene.
The formula for a 10 carbon (mono) cyclic alkene is C10H18.
This is true because for every ring structure 2 hydrogens are removed and for every double 2 hydrogens are removed in comparison with the generic alkane formula. The generic 10 carbon alkane would be C10H22. Given one ring structure and one double bond the final formula is C10H18.
In numbering a parent chain, which feature has a greater priority: halogen (e.g. Cl), a double bond, a triple bond?
A double bond and triple bond have priority over the triple bond. A double and triple bond have equal priority and the parent chain should be numbered to give the lowest possible number to either one. If both have the same number on the parent chain, then the priority is given to the double bond (but only in this situation).
In the diagram below, structure a) the triple bond has priority and in structure b) the double bond has priority.
Which of the following names of substituent would be considered first in terms of alphabetical order?
- dimethyl
- triethyl
- isopropyl
- tert-butyl
The substituent that comes first is tert-butyl as all the prefixes except “iso” are ignored. The order should be therefore (with relevant letter highlighted):
tert-butyl > triethyl > isopropyl > dimethyl
What is the correct numbering of substituents on this ring structure?
The numbering should give the methyl groups at the bottom of the ring the number 1 - therefore:
1,1,3,4-tetramethyl
What functional group is represented in this molecular structure? What is the suffix for the name?
Alcohol functional group. The suffix is - ol.
What functional group is represented in this molecular structure? What is the suffix for the name?
Aldehyde functional group. The suffix is - al.
What functional group is represented in this molecular structure? What is the suffix for the name?
Carboxylic acid functional group. The suffix is - oic acid.
What functional group is represented in this molecular structure? What is the suffix for the name?
Amide functional group. The suffix is - amide.
What functional group is represented in this molecular structure? What is the suffix for the name?
Ester functional group. The suffix is - oate.
What functional group is represented in this molecular structure? What is the suffix for the name?
Ether functional group. The suffix is -ane - that is the same as an alkane. Note that this functional group is like the halogens - it affects the molecule’s reactivity but it is named as a substituent. The name of this compound is 1-methoxypropane.
What functional group is represented in this molecular structure? What is the suffix for the name?
Ketone functional group. The suffix is - one.
What functional group is represented in this molecular structure? What is the suffix for the name?
Amine functional group. The suffix is - amine.
What functional group is represented in this molecular structure? How many carbons is the parent chain?
Amine functional group. The parent chain is four carbons long.
On what carbon of the parent chain is the amine functional group?
The amine functional group is on carbon number 2.
On what carbon is the amine functional group? On what carbon does the double bond start?
The amine functional group is on carbon 2 and the double bond starts on carbon 3.
What is the main functional group and on what carbon is it on the parent chain?
The functional group is the aldehyde and it is on carbon #1 of a three carbon parent chain.
On what carbon is the amine substituent and how is it referred to in the name?
The amine substituent is on carbon #2 and is referred to as “amino”. The name of this molecule is 2-amino-N-methylpropanal.
How many carbons is the parent chain?
The parent chain is four carbon’s long and includes both the amine functional group and the double bond as shown by the numbers below. A longer five carbon chain can be found, but it would not include the double bond.
Does this molecule have E, Z, or no stereochemistry?
This molecule has no stereochemistry because carbon 3 has identical groups attached (and therefore it is not possible to prioritize).
Does this molecule have E, Z, or no stereochemistry?
This molecule has Z stereochemistry because (as shown in the diagram) the higher priority groups on each of the stereocarbons are on the same side.
Does this molecule have R, S, or no stereochemistry?
As drawn this molecule has no stereochemistry. Although it does has a chiral carbon, the three-dimensional wedge/dash perspective is not shown.
Does this molecule have R, S or no stereochemistry?
This molecule has S stereochemistry.
What is the relationship of the molecules represented by these structures?
These molecules are enantiomers - that is non-superimposable mirror images. Notice that the methyl group and hydrogen are switched.
What is the relationship of the molecules represented by these structures?
These molecules are enantiomers - that is non-superimposable mirror images. Notice that the methyl group and fluorine are switched.
What is the relationship of the molecules represented by these structures?
These molecules are constitutional (or structural) isomers - that is they have a different attachment of atoms.
What is the relationship of the molecules represented by these structures?
These molecules are E/Z-type stereoisomers. The molecule on the left is Z and the molecule on the right is E.
What is the relationship of the molecules represented by these structures?
Although these molecules have double bonds, they have a different attachment of atoms, therefore they are constitutional (structural) isomers.
Which of the following two molecules is considered to be the nucleophile? Will this reaction occur as an SN1 or SN2?
H2O is the nucleophile and this reaction will occur as SN2. It will occur SN2 because the electrophile is primary and provides easy access for the attack by the nucleophile in one step.
Will this reaction occur as an SN1 or SN2?
This reaction will occur as SN1 because the electrophile is secondary and the nucleophile is weak. In this case, the nucleophile will not attack until the leaving group (the F-) has left, which allows access to the trigonal planat carbocation.
Will this reaction occur as an SN1 or SN2?
This reaction will occur as SN1 because the electrophile is tertiary. There is not enough room for the nucleophile to attack until the leaving group has left, leaving the trigonal planar carbocation.
Will this reaction occur as an SN1 or SN2?
This reaction will occur SN2 because the electrophile is secondary and the nucleophile is strong. Therefore the nucleophile will attack before the leaving group leaves.
Will this reaction occur as an SN1 or SN2?
This reaction will occur SN1. In spite of the fact that the nucleophile is strong, the electrophile is tertiary. Therefore the nucleophile will not attack until the leaving group leaves, exposing the trigonal planar carbocation.
