Module 2 - Ch2 Organic Compounds
A primary carbon is bonded to _____ carbon
A primary carbon is bonded to one carbon
A secondary carbon is bonded to _______ carbons
A secondary carbon is bonded to two carbon
What is T-butyl
A tertiary carbon - meaning a carbon bond that is bonded to three other carbons
A tertiary carbon is bonded to ______ carbon
A tertiary carbon is bonded to three carbons
HWQ41 Which of the molecules below has the higher boiling point? Briefly explain your choice
CH3CH2CH2OH has the higher boiling point since it is capable of intermolecular hydrogen bonding. 9
HWQ27 Draw all possible constitutional isomers for C2H6O and give common names for each structure.
Ethyl Alcohol Dimethyl ether
Mod2QuizQ9 Which conformer of cyclohexane has highest energy? chair half-chair twist-boat boat
Hal-chair
What does trans mean?
It means the substituents are on opposite sides of the ring
HWQ36 Which compound is more soluble in water? Briefly explain your choice. (CH3)2NH or CH3CH2CH3
(CH3)2NH (dimethylamine) is more soluble in water since it can hydrogen bond with water. Alkanes are not capable of hydrogen bonding with water.
HWQ21 Draw an acceptable structure for 3-ethyl-3-methylhexane
*Why would we not draw a hexagon? * does it matter whether it's on top or bottom?
The attractive forces between molecules include:
- Dispersion forces - dipole-dipole interactions - hydrogen bonds
What do we not omit in the skeletal structure?
- Do not omit heteroatom -Do not omit bond between heteroatom and carbon
HWQ24 4) Provide an acceptable name for the alkane shown below.
- In this case, we know to expand the (CH3)2, in order to get a true length of the molecule. As a result, we notice that the longest carbon is 7. We then move on to identify that the ethyl is at carbon 2, and we begin numbering the chain from there. As a result, the name of this would be 2,5-dimethyheptane
HWQ22 2) Draw the most stable conformation of trans-1-tert-butyl-3-methylcyclohexane.
- This is the most stable position, only because we would not want to have the T-butyl on the axial position, as this would be very unstable for the molecule to have the bulky substituent not in the equatorial position. We can see that it is trans, because both substituents are in different positions than each other
If an ether has different alkyl groups, thus is called an
unsymmetrical ether
If one hydrogen is replaced in NH3 by al alkyl group, this is a __________ Amine
Primary
Three types of carbons in all organic compounds: What are they?
Primary Secondary Tertiary
Classification of alcohols A primary alcohol is on a ____ carbon A secondary alcohol is on a ____ carbon A tertiary alcohol is on a ____ carbon
Primary Secondary Tertiary
If one of the hydrogens is replaced in Nh3 by an alkyl group (-R), we say this is an
Primary amine
The chair conformer of cyclohexane is completely free of ______, and therefore it is the ____stable conformer
- completely free of strain - most
HWQ13 Draw an acceptable structure for 4-t-butyloctane.
- we know that T-butyl = a bond to a carbon attached to three other carbons which makes it a tertiary carbon
HWQ20 Name the structure. * see HW
-We know that we will name this hexanol because there are 6 carbons with an OH, meaning that the -e ending will be turned into hexanol. Then we know to begin counting from the closest side to the hydroxyl functional group, as this take priority from the halogens. At the end, we know to always place them in alphabetical order. As a result, the name of this compound is 6-chloro-2-hexanol
Ring Flip
-atoms/groups that were equatorial become axial and vice versa
HWQ17 View a butane molecule along the C2-C3 bond and provide a Newman projection of the lowest energy conformer.
.The anti-form is the most stable
What is the most stable angle?
109.5 degree
HWQ3 3) Determine the number of hydrogens in limonene
16
Mod2QuizQ2 A tertiary carbon is bonded to _______ carbons.
3
HWQ12 Provide an acceptable name for the compound shown below. *see HW
3,3,5-trimethylheptane Always count the largest amount of carbons possible, that will give you the most constituents possible - we know that at the third carbon, there are 2 methyl groups located as well as the on the 5th carbon there is 1 methyl group located (3,3,5-)
HWQ37 Provide an acceptable name for the compound shown below.
3,3-dibromo-1-chloroheptane *Remember to alway label BOTH substituents like here it's 3,3
HWQ23 23) Give the systematic name of the alkane shown below *see HW
3-ethyl-4-isopropyloctane *Why is it isopropyl????? why do we not use the ethyl
Mod2QuizQ10 How many fused rings are there in steroid?
4
HWQ35 Provide the IUPAC name of the compound.
4-amino-1-butanol - we know that alcohols take naming priority, and numbering priority - So, we say that since there are 4 carbons and an alcohol it's a butane, and then we say that at the 4th carbon there is an amino group attached - we also remember that amino is NH2
HW31 Give the systematic name of the cycloalkane shown below.
4-butyl-1,2-dimethylcyclohexane
HWQ14 14) Give the systematic name of the alkane shown below.
4-ethyl-2,2,7-trimethylnonane We know that the 2,2,7 are name the three methyl groups in the compound, and since there are three methyl groups, we know that it is a "trimethyl"
HWQ33 Provide an acceptable name for the compound shown below.
5-ethyl-2-methylcyclohexanol Why is it not 5-ethyl-2-methyl-1- cyclohexane? If the methyl group is not part of the the longest carbon ring, why is this the 'methyl' in the name methylcyclohexane?
HWQ16 16) Provide an acceptable name for the compound shown below. ** see HW
5-ethyl-3,3-dimethyloctane - We know that this is indicating a two methyl groups on the third carbon, and an ethyl on the 5th carbon. We also know that we put the ethyl first because of alphabetical order
HWQ26 26) Provide the systematic name of the compound shown.
6,7-dimethyl-3-octanol * see instructions
Alcohols are named by replacing the "___" at the end of the parent hydrocarbon with the suffix "___"
Alcohols are named by replacing the "e" at the end of the parent hydrocarbon with the suffix "ol" methanol ethanol
How many bonds do Alkanes have?
Alkanes are hydrocarbons that contain only single bonds
Are alkanes more or less dense than water?
Alkanes are less dense than water - they float on water - think oil spill
If you have a tie with heteroatoms in terms of location for naming purposes, you would label the molecule based on _____ order.
Alphabetical order
The amino group in amines derrieves from?
Ammonia - NH3
If there are two of the same heteroatoms, for naing purposes of the entire molecule, do we use the di- or the meth in dimethylnonane for example?
As we are placing them in alphabetical order, we remember that it's two methyl groups, therefore we use the M in methyl to guide the naming of this molecule instead of the D in di-
Staggered conformer is more stable, but why?
Because of less static
Why is it less stable when Axial?
Because of the steric between the Hydrogens
If you add a carbon to a benzene ring missing a hydrogen, this is called?
Benzyl group
If the molecule is branched, does this increase or decrease boiling points
Branched structures lower the boiling point
Ethers Must have a structure of _______ - Oxygen- _______
Carbon---Oxygen--Carbon
HWQ29 Fluorine is more electronegative than chlorine yet the carbon-fluorine bond in CH3-F is shorter than CH3-Cl. Explain.
Chlorine is a larger atom than fluorine and uses a 3p rather than 2p orbital. The overlap of a 2sp3 orbital with a 3p orbital is not as good as the overlap of a 2sp3 orbital with a 2p orbital, causing the bond to be longer and weaker. aren't shorter bonds stronger?
Mod2QuizQ1 What is the general formula of alkane?
CnH2n+2
What is the general formula for alkanes?
CnH2n+2
Physical property of Alkanes: Where are Alkane found?
Crude-oil
Which are the three elements that can form hydrogen bonds?
FON Fluorine Oxygen Nitrogen
Alkanes Systematic Nomenclature First: Identify the _________ continuous carbon chain with the most substituents (the parent hydrocarbon)
First identify the longest continuous carbon chain with the most substituents (the parent hydrocarbon)
HWQ1 1) Which compound is more soluble in water? Briefly explain your choice CH3OCH3 or CH3CH2OH
For a substance to be soluble in water, it should form H-bonding with water. To form H-bonding the substance should be polar in nature. For a molecule to form hydrogen bonding, the hydrogen atom should be attached with one of the electronegative atoms like F, O, N. In the case of CH3OCH3 (Dimethyl ether), all of the H-atoms are attached with a Carbon, which creates a stable nonpolar molecule with less electronegativity. As a result, it does not form H-bonding with water. However, CH3CH2OH (methanol) has one H atom directly bonded with the high electronegativity O atom, thus creating a polar molecule and can for H-bonding with water. However, we know that CH3OCH3 (Dimethyl ether) is also soluble in water as alcohol with less than 4 carbon usually are. However, CH3OCH3(Dimethyl ether) can only accept a hydrogen bond from water, as it has no hydrogen which can hydrogen bond to water. As opposed to CH3CH2OH (MEthanol), which is more soluble in water since it can donate a hydrogen to water and accept a hydrogen to water
HWQ15 Draw the most stable conformer of the following compound
Here, we know that is best to position the conformer in an Cis configuration with bother substituents in an equatorial set-up. However, the question then remains, how did we know the substituents were methyl group and an ethyl group?
HWQ8 Draw the most stable conformer of cis-1-ethyl-2-methylcyclohexane
How come the Ch3 is an axial position instead of an equatorial position
Why is the boat conformation of cyclohexane less stable?
Hydrogen steric interactions or hyderance (flagpole H)
How do we label primary, secondary, and tertiary Hydrogens?
Hydrogens carry the label of the carbon. So if a hydrogen is attached to a primary carbon, we say that it is a primary hydrogen
HWQ25 Draw the most stable conformer of trans-1-ethyl-3-methylcyclohexane.
If we are searching for the most stable, why do we place the CH3 in the axial position VS the equatorial position, wouldn't we want it to be in the most stable position????
What if the substituent has more carbon than the cycloalkane?
In this case, we know to treat the cycloalkane structure as the heteroatom, and treat the longest carbon chain is the parent hydrocarbon
HWQ2 Draw the most stable conformer of cis-1-ethyl-4-methylcyclohexane, the 2-D structure is shown as following:
In this case, we note that the CH3 is pointing down in the axial position, and CH2CH3 is pointing downward in the equatorial position
What does cis- mean?
It means that the substituents are on the same side of the ring
When staggered is the energy lower or higher and is it more or less stable?
Less energy, more stable
Mod2QuizQ6 Which of the following compound can form hydrogen bond with each other? HCl H2S NH3 CO2
NH3
Do Alkanes contain heteroatoms?
No, Alkanes do not contain heteroatoms. Alkanes only contain Carbons and Hydrogens
Is a substituent a complete molecule?
No, a substituent is considered a 'branch' or a part of a molecule but it is not considered a complete molecule
When classifying amines are we concerned with the classification of the carbon it is attached to in terms of primary,secondary, tertiary status?
No, differentiating from Halides and Alcohols, when we look at amines, we know that we are only concerned with the number of hydrogens replaced by the alkyl groups.. we don't worry about the classification of the carbon
Alkanes Systematic Nomenclature: Second Step: Number the chain in the directions the gives substituents as ________ number as possible AKA we want to see the substituents as ______ early as possible
Number the chain in the direction that gives substituents the lowest number possible We want to see the substituents as early as possible
Systematic names of alcohols When naming alcohols, we know that the OH is the ________ group
OH in alcohols is the functional group
Alkane-Saturated hydrocarbons: Skeletal structure what do we omit?
Omit the symbols of C and H, omit the C-H bond
HWQ37 Would you expect sodium chloride (NaCl) to be highly soluble in the organic solvent hexane (CH3CH2CH2CH2CH2CH3)? Briefly explain your answer.
One would not expect NaCl to be highly soluble in hexane. NaCl is an ionic solid (i.e., a very polar material) while hexane is nonpolar. Nonpolar solvent molecules do not solvate ions well. The attractions of oppositely charged ions to each other are vastly greater than the weak attractions of the ions for the solvent.
Phenyl and Benzyl substituents: If you remove one hydrogen from the benzene, this will form a
Phenyl group
Dipole-Dipole interactions exist in ?
Polar molecules
What does the R- stand for ?
R-- stand for any alkyl group
HWQ6 Draw an acceptable structure for sec-butylcyclopentane.
Refer to PPT The butyl group is attached two a secondary carbon A secondary carbon is attached to two carbons
Alkyl Substituents: What does removing a hydrogen from an alkane results in?
Removing a hydrogen from an alkane results in an alkyl substituent
Cycloalkanes Cycloalkanes are ___ shaped alkaned
Ring shaped alkanes
HWQ28 Explain why trimethylamine, (CH3)3N:, has a considerably lower boiling point than propylamine CH3CH2CH2NH2, even though both compounds have the same molecular formula.
Since hydrogen bonding is possible for propylamine and not for trimethylamine, the boiling point is higher for propylamine.
If an ether has the same alkyl group, it is a called a
Smetrical ether
Systematic nomeclature uses a _____ to denotes a functional group
Systematic nomeclature uses a SUFFIX to denote a functional group
What does the -X reprents?
The -X represent halo groups
What is isopropyl?
The bond is attached to a secondary carbon
The difference between propyl and isopropyl is that the isopropyl is attached to _____ carbons and propyls is attached to _____ carbon(s)
The difference between propyl and isopropyl, is that isopropyl is attached to two carbons (secondary carbon), and propyl is attached to one carbon (primary carbon)
Systematic names of alcohols When there is noth a functional group and a substituent, the functional group gets the ______ number
The functional group gets the lowest number
The greater the __________ forces between molecules, the _________ the boiling point
The greater the attractive forces between molecules, the higher the boiling point
What are the Halo groups?
The halo groups are halo substituents for the halogens Fluoro: - F Chloro: - Cl Bromo: -Br Iodo: -I
The _________ the substituent, the more the ________-__________ conformer will be favored
The larger the substituent, the more the equatorial-substituted conformer will be favored
Are alkanes polar or non-polar? If so, are they soluble or non-soluble in water?
They are nonpolar - insoluble in water - hydrophobic
What happens if we remove a hydrogen from methane?
This creates a methyl group CH3--
What if we remove a hydrogen from a methane?
This creates a methyl group CH3CH2--
HW30 Which intermolecular force is primarily responsible for the interactions among alkane molecules?
Van der Waal's or London forces In alkanes there are all almost non-polar bonds, Hence there is no possibility of strong interaction. In alkanes dispersion forces / London forces are possible only. These London forces have strength even less than 1 kcal/mol. These are the weakest possible interactions.
What happens if we have the same functional group attached to a benzene ring?
We can abbreviate the name using the ArOH Aromatic refers to benzene
HWMCQ1 A.2-bromo-5-methylheptane
We know this because? We count the highest number of carbons first with the halogens taking priority
When it comes to Alkane's Alkyl substituents, what doe we replace the "ane" with? Give an example
We replace the -ane with -yl For example instead of methane, we say methy
Described the trans- isomer
When two substituents are facing in opposite direction (down or up)
Described Cis- isomer
When two substituents are pointing to the same side (downward or upward)
HWQ9 Draw the most stable conformer of trans-1-ethyl-4-methylcyclohexane
Why can't the CH3 be axial
HWQ11 Draw an acceptable structure for 4-isopropyl-2-methylheptane.
Why is it isopropyl?. - like where do we get the iso from Why is it a methylheptane instead of isoheptane ?
HWQ19 Draw the most stable conformer of cis-1-isopropyl-2-methylcyclohexane.
Why is this the most stable if the CH3 is Axial, does not make sense? Alos, is the isopropyl in an equatorial position?
HWQ10 Draw a Newman projection of the most stable conformation of 2-methylpropane
Why the hydrogens
Doe boiling point change if the structure of the molecule changes?
Yes
Are dipole dipole interaction stronger than dispersion forces?
Yes, dipole-dipole interactions are stronger than van der waals forces
Do we put substituents in alphabetical order?
Yes, substituents a placed in alphabetical order
Are Alkanes flammable?
Yes, they are flammable in air
Mod2QuizQ7 Which of the following compound has relatively highest boiling point? methane ethane propane butane
butane
Mod2QuizQ8 Which of the following compound has least ring strain? cyclopropane cyclobutane cyclopentane cyclohexane
cyclohexane
Boiling points continued* What is the only intermolecular force of non-polar compounds?
dispersion forces which is a temporary or induced dipole-dipole interaction It has to do with the molar mass of the compound. If the molecule is bigger, then boiling point will be higher due to surface area.
Mod2QuizQ4 What is the family name of R-O-R ?
ether
When it comes to naming 'alphabetical priority' - we know that _______________ has a higher priority then ________________
ethyl VS methyl
Hydrogen bonds are ______ than other dipole dipole interactions
hydrogen bonds are stronger than other dipole-dipole interactions
Does having hydrogen bond increase or decrease boiling point?
increase
Branching _____ the boiling point. This means that the dispersion forces are _____
lowers weaker
Priority of functional group in nomenclature In nomenclature, we keep the highest priority group as _____ #
lowest number
Mod2QuizQ3 What is the classification of ethanol?
primary alcohol
A primary alkyl halide is on a _____ carbon
primary carbon
If two hydrogens are replaced by an alkyl group in NH3, this is an _______ amine
secondary
If two hydrogens are replaced in NH3 with an alkyl group, we say this is a
secondary amine
A secondary Alkyl Halide is on a ____ carbon
secondary carbon
Since gauge interactions = static hinderance, we can say that the newman projection with the least amount of gauge interactions is the most_______
stable
If the methyl group is in equatorial position, this mean this a more ____ chair conformer. Which mean it has _____ energy
stable lower
If three hydrogens are replaced in NH3 by an alkyl group this is called a _____________amine
tertiary amine
If three hydrogens are replaced in NH3 by three alkyl groups we say this is a
tertiary amine
Mod2QuizQ5 What is the classification of trimethylamine?
tertiary amine
A tertiary alkyl halide is on a _____ carbon
tertiary carbon