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238
Step. 2.
The Kc/R
θ
=0
(zero angle) values obtained by extrapolation obey the much
simpler equation (zero angle limit):
Kc
R
θ
=
0
=
1
M
w
+
2
A
2
c
+
...
⎛
⎝⎜
⎞
⎠⎟
Note this is exactly the same equation obtained for small molecules (isotropic
scatterers). Thus the next step is to plot these values according to the
equation:
The intercept gives 1/M
w
, thus M
w
= 198.000 g/mol. The slope gives 2A
2
, thus
A
2
= 3.0
⋅
10
-3
ml mol
-1
g
-1
.
Step. 3.
0.0E+00
5.0E-06
1.0E-05
1.5E-05
2.0E-05
2.5E-05
0.0
0.2
0.4
0.6
0.8
1.0
sin
2
(
!
/2)
Kc/R
!
c1
c2
c3
c4
y = 6.00E-03x + 5.05E-06
0.0E+00
2.0E-06
4.0E-06
6.0E-06
8.0E-06
1.0E-05
1.2E-05
1.4E-05
1.6E-05
0.0000
0.0005
0.0010
0.0015
c (g/ml)
Kc/R
!
=