
55-46 Chemical Variables
55.5.1 Measurement of Conductance and Instrumentation
e conductance G of a solution is the reciprocal of the electrical resistance R and has the units of sie-
mens
(S
)
th
at
co
rrespond
to oh
m
−1
(Ω
−1
). e conductance of a uniform sample with the length l and
cr
oss-sectional
a
rea
A i
s
g
iven
b
y
G
A
l
=
κ
(55.56)
where
th
e
pr
oportionality
co
nstant
κ = 1/ρ (ρ: re
sistivity)
de
scribes
th
e
co
nductivity
(sp
ecic conduc-
tance)
of th
e
so
lution,
ex
pressed
in un
its
of S cm
−1
. e equivalent conductivity Λ (molar conductivity)
of a so
lution
is de
ned
as th
e
co
nductivity
du
e
to on
e
mo
le,
me
asured
be
tween
tw
o
el
ectrodes
th
at
ar
e
sp
aced
1 c ...