Parr Instrument 6725 User Manual
Page 52
6725
Semi-micro Calorimeter Instruction Manual
6-4
Example:
Where:
16.03 is equal to the equivalent weight of sulfur in H
2
SO
4
e
1
is the nitric acid portion of the total acid correction
e
2
is the sulfuric acid portion of the total acid correction
e
1
+e
2
is the total bomb acid correction
Sulfur Multiplier Calculation:
6238
0
10
.
4
SO
2
H
in
sulfur
of
weight
equivalent
4
SO
2
H
of
alents
milliequiv
4
SO
2
H
in
sulfur
of
weight
equivalent
(mg)
Sulfur
(mg)
Sulfur
10
mass
Sample
%Sulfur
=
=
=
Ч
Ч
Acid Multiplier Calculation:
0.0709
formation
HNO
to
due
calories
)
HNO
of
)(H
HNO
of
valents
(milliequi
HNO
of
alents
milliequiv
SO
H
of
alents
milliequiv
-
alents
milliequiv
acid
Total
3
3
f
3
3
4
2
=
=
=
Sulfur Correction
e2 = (percent sulfur)(sample mass)(sulfur multiplier)(heat of formation of H2SO4).
Acid Correction
In the 6772 there are a number of settings for the acid correction.
e1 is the nitric acid portion of the correction.
Fixed HNO3: The Acid Correction is a fixed value set by the operator.
The calculation is:
e1 = (nitric acid value)(acid multiplier)(heat of formation of nitric acid)
For an 1109A bomb the default nitric acid value is 1.5 and acid multiplier is .0709. The
heat of formation of nitric acid is 14.1 calories/milliequivalent so the calculation is:
e1 = (1.5)(.0709)(14.1) or e1 = 1.499535 calories (rounds to 1.5)
When the Acid Correction is set to Fixed HNO3 the value is considered a final value and
the operator is not prompted for an acid value when reporting the results.
Entered HNO3: The Acid Correction is entered by the operator when reporting the
results.
The calculation is the same as Fixed HNO3 above. The value listed on the Acid
Correction button is used for preliminary calculations. When finalizing the report the
operator will be prompted for the acid value.