Fall 2015
CHY482
Take
–
home final exam
Due date:
Mon
day December 15, 2015 at 1800 via email
The c
rystallization
of materials
such as
wax
es
, triglycerides
and
polymers
involves the
nucleation and growth of molten
species
into an ordered crystal lattice
typically as a result of
cooling
.
During solidification,
the surface of
newly
–
formed
crystals
is
surrounded by
layers of
molten species
that are about to
solidify (i.e., in an incipient state of crystallization)
.
To this day,
however,
there remains
little
information
regarding
the
solid
–
liquid
interfacial tension
(
?
s
l
)
that
exists between the solidified material and its liquid
–
state counterpart
. Presumably
the value of
?
s
l
is low
(likely well below 1 mN/m)
, though there exists little scientific validation o
f this point.
Nevertheless
, numerous
models over the
past few years
have tended towards this conclusion.
Taking into account everything that you have been exposed
to in CHY482 as well as the large
body of information available in monographs and peer
–
revie
wed
scientific journal articles
, please
answer the following questions
.
The % breakdown is shown in brackets following each question
:
i)
Please
provide a definition
of
?
s
l
(20%).
ii)
What are the intra
–
and inter
–
molecular forces
at play in
?
s
l
(40%)?
iii)
Using the scientific literature on research in
many
fields as a guide (e.g., polymers,
pharmaceutical,
food science,
etc.)
, please provide
and describe
possible methods that
are (or may be)
used to determine
?
s
l
.
Your chosen approach(es) may be
experimental
and
/or
computer simulation
–
based
(40%)
.
You must work individually
. Answers to these questions should total 6
pages maximum
double
–
spaced. Other pages may consist of your title page, references, etc. Within the 6 pages, you may
wish to includ
e figures that assist in conveying a certain point. Please do not feel that you have to
fill the 6 pages! Use 12 pt Times New Roman font and 1” margins. You
must
include 5 relevant
references in a consistent referencing style.
The course notes are one acceptable reference.
12
Fall 2015
CHY482
Take
–
home final exam
Due date:
Mon
day December 15, 2015 at 1800 via email
The c
rystallization
of materials
such as
wax
es
, triglycerides
and
polymers
involves the
nucleation and growth of molten
species
into an ordered crystal lattice
typically as a result of
cooling
.
During solidification,
the surface of
newly
–
formed
crystals
is
surrounded by
layers of
molten species
that are about to
solidify (i.e., in an incipient state of crystallization)
.
To this day,
however,
there remains
little
information
regarding
the
solid
–
liquid
interfacial tension
(
?
s
l
)
that
exists between the solidified material and its liquid
–
state counterpart
. Presumably
the value of
?
s
l
is low
(likely well below 1 mN/m)
, though there exists little scientific validation o
f this point.
Nevertheless
, numerous
models over the
past few years
have tended towards this conclusion.
Taking into account everything that you have been exposed
to in CHY482 as well as the large
body of information available in monographs and peer
–
revie
wed
scientific journal articles
, please
answer the following questions
.
The % breakdown is shown in brackets following each question
:
i)
Please
provide a definition
of
?
s
l
(20%).
ii)
What are the intra
–
and inter
–
molecular forces
at play in
?
s
l
(40%)?
iii)
Using the scientific literature on research in
many
fields as a guide (e.g., polymers,
pharmaceutical,
food science,
etc.)
, please provide
and describe
possible methods that
are (or may be)
used to determine
?
s
l
.
Your chosen approach(es) may be
experimental
and
/or
computer simulation
–
based
(40%)
.
You must work individually
. Answers to these questions should total 6
pages maximum
double
–
spaced. Other pages may consist of your title page, references, etc. Within the 6 pages, you may
wish to includ
e figures that assist in conveying a certain point. Please do not feel that you have to
fill the 6 pages! Use 12 pt Times New Roman font and 1” margins. You
must
include 5 relevant
references in a consistent referencing style.
The course notes are one acceptable reference.
