The Students' Guide in Quantitative Analysis - Free Ebooks Library

QUANTITATIVE ANALYSIS.
J uo(;t{e Add it to loo c.c. of distilled
in a glass st.PP^^'
^^^^^i^^^ f,3^,, the burette and shake
::;r'arco:tLue addi.^ soap solution until a lather
Lmed of sufficient consistence to renjajn for Bve
l^inutes on the surface of the water. Read burette and
calculate.
Repeat.
, ,, , if.;.
In certain cases allowance should be made or the
amount of soap solution destroyed by water itself ; loo
c.c. destroys 0.8 c.c. soap solution.
Perfatmance of Amfysis.-Same as above. Report mil-
ligrammes per Utre and grains per gallon of CaCO,.
"Example.— -iocc. of the standard solution of chloride of
calcium required 23 c.c. of soap solution—
But 10 c.c. of CaCU solution is equivalent to .oi grm.
of CaCOj, hence
c-c. used ,
I
23 )
^ ^^ f _
--
\:a— .00043 gnns
And if 100 c.c. of water under examination require
33 c.c. of CaCl, solution, we have 33X. 00043 X 10 = grms.
per litre of CaCOj. This gives .1419; and .1419X.058318
gives grains per gallon. For the factor .05S318 consult
I, Calculaiion of Results,
E. Permanganate Test for Organic Matter.
Principle.—Permanganate of potassium in solution oxi-
dizes putrescible organic matter.
PreparaticH of solution of fertnanganate, — Dissolve
0.320 grms. of permanganate in I litre of water. Dis-
solve 0.7875 pure oxalic acid in i litre of water, weighing
very accurately. Of this solution i c.c.=o.oooi grm. oxy