MODULE 7 - ORGANIC CHEMISTRY QUESTIONS WITH
COMPLETE SOLUTIONS VERIFIED LATEST UPDATE.Buy
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What is a chain isomer
Compounds with the same molecular formula but different structures of the carbon
skeleton
What is a position isomer?
Molecules have the same carbion chain but the functional group is in a different location
What is a functional group isomer?
Have different functional groups,They belong to different homologous series.
What are dispersion forces?
The weakest of all molecular interactions and caused by the motion of electrons. They
occur between nonpolar molecules
-Strength increases with increasing molar mass
-Present in all substances .
What are dipole-dipole forces?
forces of attraction between polar molecules
-Strength increases with increasing dipole moment (difference in elctronegativity)
What are hydrogen bonds?
very strong intermolecular attraction between a H covalently bonded to N,O or F
BP and MP within Hydrocarbons
-Boiling and melting points increase with chain length
>As chain length increases, molecular mass increases
> Hence the strength of dispersion forces will increase
>More heat energy is required to break the stronger intermolecular forces and cause
boiling
How can high MP and BP be explained by packing
Due to their small size,methane and ethane pack more efficenctly
Hence the strength of intermolecular forces will increase
More heat energy is required to break the stronger intermolecular forces and cause
melting
What Homologous series have what type of bonding?
Carboxylic Acid=Hydrogen Bonding
Ester=Dipole-dipole
Amide=Hydrogen Bonding
Aldehyde=Dipole Dipole
, Ketone=Dipole dipole
Alcohol=Hydrogen Bonding
Amine=Hydrogen bonding
Alkene,Alkane,Alkyne=Dispersions
What Homologous series have highest Boiling points?
Amides,due to presence of networks of hydrogen bonding
Why does carboxylic acids have a higher boiling point than amines and alcohols?
Carboxylic acids can form tywo hydrogen bonds with the double oxygen bond
Whereas each amine or alcohol molecule can only form one hydrogen bond with anoth
amine or alchol molecule
Hydrocarbon Boiling point order
Alkyne>Alkane>Alkene
Alkenes have ow molecular mass than alkanes,so strength of intermolecular force is
weaker and boiling point is lower
Alkynes also have low molecular mass,but the triple bond allows for closer packing
Alcohol Boiling point strength
Secondary and tertiary alcohols have lower boiling points than primary alcohols
Hydrogen bonding is weaker in secondary and tertiary alcohols because of the
neigbouring alkyl groups hinder the OH groups from getting closer together,leading to
weaker hydrogen bonding
Amide/Amide boiling point strength
Primary>Secondary>Tertiary
Secondary amines and amides have one less hydrogen bond donor compared to
primary,thus less hydrogen bonds can form
For tertiary amines and amides hydrogen bonds cannot form
What does Solubility depend one?
Solute-solute cohesive forces
Solvent-solvent cohesive forces
solute-solvent adhesive forces
What makes a substance soluble?
If a subatnace is soluble,the adh3esive forces are strong enough to break the cohesive
forces to cause mixing at a molecular level (i.e dissolution)
What makes a substance insoluble?
Adhesive dispersion forces between hexane and water are not strong enough to break
the cohesive hyfrogen bonds in water and the cohesive dispersions forces in
hexane,therefore hexane will not dissolve in water
COMPLETE SOLUTIONS VERIFIED LATEST UPDATE.Buy
Quality Materials
What is a chain isomer
Compounds with the same molecular formula but different structures of the carbon
skeleton
What is a position isomer?
Molecules have the same carbion chain but the functional group is in a different location
What is a functional group isomer?
Have different functional groups,They belong to different homologous series.
What are dispersion forces?
The weakest of all molecular interactions and caused by the motion of electrons. They
occur between nonpolar molecules
-Strength increases with increasing molar mass
-Present in all substances .
What are dipole-dipole forces?
forces of attraction between polar molecules
-Strength increases with increasing dipole moment (difference in elctronegativity)
What are hydrogen bonds?
very strong intermolecular attraction between a H covalently bonded to N,O or F
BP and MP within Hydrocarbons
-Boiling and melting points increase with chain length
>As chain length increases, molecular mass increases
> Hence the strength of dispersion forces will increase
>More heat energy is required to break the stronger intermolecular forces and cause
boiling
How can high MP and BP be explained by packing
Due to their small size,methane and ethane pack more efficenctly
Hence the strength of intermolecular forces will increase
More heat energy is required to break the stronger intermolecular forces and cause
melting
What Homologous series have what type of bonding?
Carboxylic Acid=Hydrogen Bonding
Ester=Dipole-dipole
Amide=Hydrogen Bonding
Aldehyde=Dipole Dipole
, Ketone=Dipole dipole
Alcohol=Hydrogen Bonding
Amine=Hydrogen bonding
Alkene,Alkane,Alkyne=Dispersions
What Homologous series have highest Boiling points?
Amides,due to presence of networks of hydrogen bonding
Why does carboxylic acids have a higher boiling point than amines and alcohols?
Carboxylic acids can form tywo hydrogen bonds with the double oxygen bond
Whereas each amine or alcohol molecule can only form one hydrogen bond with anoth
amine or alchol molecule
Hydrocarbon Boiling point order
Alkyne>Alkane>Alkene
Alkenes have ow molecular mass than alkanes,so strength of intermolecular force is
weaker and boiling point is lower
Alkynes also have low molecular mass,but the triple bond allows for closer packing
Alcohol Boiling point strength
Secondary and tertiary alcohols have lower boiling points than primary alcohols
Hydrogen bonding is weaker in secondary and tertiary alcohols because of the
neigbouring alkyl groups hinder the OH groups from getting closer together,leading to
weaker hydrogen bonding
Amide/Amide boiling point strength
Primary>Secondary>Tertiary
Secondary amines and amides have one less hydrogen bond donor compared to
primary,thus less hydrogen bonds can form
For tertiary amines and amides hydrogen bonds cannot form
What does Solubility depend one?
Solute-solute cohesive forces
Solvent-solvent cohesive forces
solute-solvent adhesive forces
What makes a substance soluble?
If a subatnace is soluble,the adh3esive forces are strong enough to break the cohesive
forces to cause mixing at a molecular level (i.e dissolution)
What makes a substance insoluble?
Adhesive dispersion forces between hexane and water are not strong enough to break
the cohesive hyfrogen bonds in water and the cohesive dispersions forces in
hexane,therefore hexane will not dissolve in water
