December 3 - 12/2/10
 Stop
Dec.
1
...

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Unformatted text preview: 12/2/10
 Stop
Dec.
1
 Raoult’s
Law
Problem
 •  Calculate
the
vapor
pressure
lowering,
ΔP,
when
10.0
mL
of
 glycerol
(C3H8O3)
is
added
to
500.
mL
of
water
at
50.0
°C.
At
this
 temperature,
the
vapor
pressure
of
pure
water
is
92.5
torr
and
its
 density
is
0.988
g/mL.
The
density
of
glycerol
is
1.26
g/mL.
 PLAN:
Find
the
mol
frac5on,
c,
of
glycerol
in
solu5on
and
 mul5ply
by
the
vapor
pressure
of
water.
 1
 12/2/10
 Prac5ce
Problem
 You add 1.00 kg of ethylene glycol (C2H6O2) antifreeze to your car radiator, which contains 4450 g of water. What is the freezing point of new the solution? Kf H2O = 1.86 oC/m Possible
Answers:

(A)

0.00673
°C





(B)

6.73
°C




(C)

–6.73
°C





(D)

3.62
°C


 PLAN: Find the # moles of ethylene glycol; m of the solution; multiply by the boiling or freezing point constant; add or subtract, respectively, the changes from the boiling point and freezing point of water. 2
 12/2/10
 Ion
pairing
(above)
can
reduce
 ”effec5ve”
van’t
Hoff
factor
 van’t
Hoff
factor
 Prac5ce
Problem
 Consider the following aqueous solutions: 0.02 m NaCl, 0.04 m CaCl2, and 0.02 m CH3CH2OCH2CH3. Assume ideal behavior. Which solution would display the highest boiling point elevation? A.
0.02
m
NaCl
 B.
0.04
m
CaCl2
 C.
0.02
m
CH3CH2OCH2CH3
 3
 12/2/10
 End
of
Fall
‘10
Intro.
Chem.
Course
 •  Will
post
PracVce
Exam(s)
/
QuesVons
 •  Help
Sessions
 
Next
Week,

 –  Monday,
Tuesday
Wed.,
regular
evening
Vmes.
 –  Remsen
Hall

140,
3‐5:00
pm
Thursday
Dec.
9th
 Monday
Dec.
13,
evening
 Review
Sessions
planned
 
Thursday,
Dec.
9th,

noon
–
2:00
pm
(Room
??)
 
Monday,
Dec.
13th,
noon
–
2:00
pm

(Room
??)
 Homework
Problems,
OWL
Chapter
11.

3,
25,
51.


Due
 
rely
on
previous/pracVce
exam
quesVons
 FINAL
EXAM
 Intro.
Chem.
030.101.01


Sec5on
1,
Prof.
K.
D.
Karlin
 



Tuesday,
December
14










9:00
am

to

noon
 Final
Exam
Rooms/Assignments
 Remsen
1:
Last
Names




A‐L





(147
students)
 Shaffer
100:
Last
Names


M‐Q




(51
students)
 Krieger
205:
Last
Names


R‐Z





(74
students)
 Special
Circumstance
Students:
 
Meet
at
8:55
am,
NCB
213
(K.D.
Karlin
office)
 4
 ...
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This note was uploaded on 04/08/2012 for the course CHEM 101 taught by Professor Draper during the Spring '06 term at Johns Hopkins.

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