chem 219 module 2 Test with Questions Solved
100% Correct | Latest Update
What does the squiggle bond mean? - ✔✔Point of attachment to the parent chain.
Butyl or n-butyl - ✔✔-CH2CH2CH2CH3
sec-butyl - ✔✔CH3CHCH2CH3
isobutyl - ✔✔
tert-butyl - ✔✔
Isobutyl would be alphabetized as? While sec-butyl would be alphabetized as? - ✔✔I,
B
What does R represent? - ✔✔It is a generic/wildcard notation in organic structure.
Any alkyl group.
This is known as R-group notation.
Why is R chosen? - ✔✔It is not on the chart anywhere.
What is the important thing to know about the physical properties of alkanes. -
✔✔They will show similar trends in terms of their physical properties.
,What does the physical properties of a molecule refer to? - ✔✔Characteristics like
melting point, boiling point, density, solubility.
How do you compare the boiling point of alkanes? - ✔✔The longer the length of
carbon, the higher the Boiling point. When it is branched, it can have a higher boiling
point, as long as it isn't the parent chain that is branched.
Are alkanes soluble in water? - ✔✔They are water-insoluble.
Are alkanes polar or non-polar? - ✔✔Almost non-polar
What is hydrogen bonding? - ✔✔The water molecules are attracted to each other
like magnets because of it's electron rich O atom possessing a -charge and its electron
poor H possessing a + charge
What will a mixture of alkane and water make? - ✔✔A two layer-biphasic system. It
will float on top of water. since its density is less than 1g/ml
Are liquid alkanes used as solvents? - ✔✔Yes for other non polar substances.
When compared to other polar molecules of similar weight, are alkanes lower or higher
in melting and boiling points? - ✔✔They are lower.
What are Van der Waals forces? - ✔✔The attractive forces between molecules.
The polarization in VDWF's are: - ✔✔Temporary and weak
, What is the relationship between branching and VDWF? - ✔✔As you branch out you
gain more surface area and lower the VDWF. Which lowers the BP and MP
Alkanes can adopt different conformations, What does this mean? - ✔✔This means
that it can change shapes as it can rotate around bonds.
Hydrogen bonding and VDWFS are classifies as nonbonding intermolecular forces, what
does this mean? - ✔✔That they are attractive forces between molecules that are not
true bonds in the sense of sharing or donating.
What are conformers? - ✔✔Different shapes of molecules that are derived by
rotations of single bonds.
What does the Newman projection do? - ✔✔It shows the conformation of molecules
when looking down a particular bond axis.
What is the difference in hydrogen placement between an eclipsed confirmation and a
staggered one? - ✔✔The hydrogens do not overlap in staggered but they do in
eclipsed.
Certain conformers are called rotamers, why? - ✔✔They can simply be rotated into
the other conformer. Used with newman projections
Staggered vs. Eclipsed Conformers - ✔✔Staggered are generally more stable, because
of the removed repulsion that occurs when electrons are aligned on top of each other in
an eclipsed.
100% Correct | Latest Update
What does the squiggle bond mean? - ✔✔Point of attachment to the parent chain.
Butyl or n-butyl - ✔✔-CH2CH2CH2CH3
sec-butyl - ✔✔CH3CHCH2CH3
isobutyl - ✔✔
tert-butyl - ✔✔
Isobutyl would be alphabetized as? While sec-butyl would be alphabetized as? - ✔✔I,
B
What does R represent? - ✔✔It is a generic/wildcard notation in organic structure.
Any alkyl group.
This is known as R-group notation.
Why is R chosen? - ✔✔It is not on the chart anywhere.
What is the important thing to know about the physical properties of alkanes. -
✔✔They will show similar trends in terms of their physical properties.
,What does the physical properties of a molecule refer to? - ✔✔Characteristics like
melting point, boiling point, density, solubility.
How do you compare the boiling point of alkanes? - ✔✔The longer the length of
carbon, the higher the Boiling point. When it is branched, it can have a higher boiling
point, as long as it isn't the parent chain that is branched.
Are alkanes soluble in water? - ✔✔They are water-insoluble.
Are alkanes polar or non-polar? - ✔✔Almost non-polar
What is hydrogen bonding? - ✔✔The water molecules are attracted to each other
like magnets because of it's electron rich O atom possessing a -charge and its electron
poor H possessing a + charge
What will a mixture of alkane and water make? - ✔✔A two layer-biphasic system. It
will float on top of water. since its density is less than 1g/ml
Are liquid alkanes used as solvents? - ✔✔Yes for other non polar substances.
When compared to other polar molecules of similar weight, are alkanes lower or higher
in melting and boiling points? - ✔✔They are lower.
What are Van der Waals forces? - ✔✔The attractive forces between molecules.
The polarization in VDWF's are: - ✔✔Temporary and weak
, What is the relationship between branching and VDWF? - ✔✔As you branch out you
gain more surface area and lower the VDWF. Which lowers the BP and MP
Alkanes can adopt different conformations, What does this mean? - ✔✔This means
that it can change shapes as it can rotate around bonds.
Hydrogen bonding and VDWFS are classifies as nonbonding intermolecular forces, what
does this mean? - ✔✔That they are attractive forces between molecules that are not
true bonds in the sense of sharing or donating.
What are conformers? - ✔✔Different shapes of molecules that are derived by
rotations of single bonds.
What does the Newman projection do? - ✔✔It shows the conformation of molecules
when looking down a particular bond axis.
What is the difference in hydrogen placement between an eclipsed confirmation and a
staggered one? - ✔✔The hydrogens do not overlap in staggered but they do in
eclipsed.
Certain conformers are called rotamers, why? - ✔✔They can simply be rotated into
the other conformer. Used with newman projections
Staggered vs. Eclipsed Conformers - ✔✔Staggered are generally more stable, because
of the removed repulsion that occurs when electrons are aligned on top of each other in
an eclipsed.
