CH ENGR 101C Quiz: HW9 solution
9 Jan 2019
School
Department
Course
Professor
28-7
28.5
,
!
" # $
$%&' ( ) * (
s
m
air
2
5
10505.1 −
×=
υ
a. Sc and Sh
( )
( )
2
5
2
4
4
2
5
1/2 1/3
1/2 1/3 4
1.505 10
1.88
0.080 10
1.5 0.5
v
Re 4.98 x 10 laminar
1.505 10
0.664 Re 0.664 4.98 10 1.88 183
air
AB
L
L L
m
s
Sc Dm
s
mm
Ls
m
s
Sh Sc
υ
ν
−
−
∞
−
×
= = =
×
⋅
= = =
×
= = × =
b. Solvent evaporation rate, WA
( )
( )
2
cm
183 0.08 s
cm
= 0.293
50 cm s
AB
c
Sh D
kW
⋅
= =
(
)
( )
*
-6
3
3
,
0.159 atm
gmole
= 6.61 x 10
cm
cm atm
82.06 293 K
gmole K
0
A
As
A
p
cRT
c∞
= =
⋅
⋅
=
(
)
( )
,
2
-6
3
2
cm gmole 100 cm gmole
0.293 6.61 x 10 -0 2 0.5 m 2.5 m = 0.048
s cm 1 m s
A A c As A
W N S k c c WL
∞
= = − ⋅ =
⋅ ⋅
c. Determine +,
+- ./
.012342
5 .012342
6
Mass balance on solvent in moving sheet
IN – OUT – GEN = ACC
,0 ,
, ,0
0 0
0.048 86
0.10 0.017
50
s s
A A f A A
A A
A f A
s
X m X m W M
gmole g A
s gmole
W M
g A g A
X X g poly
g poly g poly
ms
• •
•
− − + =
= − = − =
2
