The Students' Guide in Quantitative Analysis - Free Ebooks Library

POTABLE WATER. 97
0.152 grains Na corresponds however to 0.204 grains
NajO making then a proportion similar to f i) wc have
(2) Na,0 : SOj " r
Amount
of Na,0
62 : 80 = 0.204 :
X =: 0.263 gi'sins.
Amount of SO,
needed
for the NajO.
X
hence 0.204 ~{- 0.263 =^ 0.467 grains NajSO^.
But the water contains 0.340 grains SOj hence we have
0.340 — 0.263 =: 0,077 grains SOj left over to combine
with CaO.
(3) CaO
Accordingly we have the proportion
f SO^ — : f Amount of SOj Amount of CaO
] J
80 :
56=
[ remaining. J"
[needed for the SO^,
0.077 : y J
y = 0.0539 grains CaO,
hence 0.077 + 0.0539= 0.130 grains CaSO^.
Proceeding in liice manner the CaO remaining is regarded
as combined with COj.
0.804 — 0.0539 = 0.7501 grains CaO and since.
;
(4) CaO CaCO, = 07501 ^
whence 1.34 grains Ca CO,. I
Collecting the results of the calculation we have (thus
far) the following figures for the constituents combined:
NaCl = 0.354