Parr Instrument 6200 - Manual (Page 60)

61
6200
Calorimeter Operating Instruction Manual
Calculating the
Heat of
Combustion
General
Calculations
The 6200 Calorimeter will automatically
make all of the calculations necessary to
produce a gross heat of combustion for the
sample. However, it is important that the user
understand these calculations to ensure the
instrument is set up so the
calculations match the
procedures and the units are
consistent throughout the
process.
The calculation for the gross heat of
combustion is done by:
H
c
=
Where:
Hc =
Gross heat of combustion.
T = Observed temperature rise.
W = Energy equivalent of the
calorimeter being used.
e
1
= Heat produced by burning
the nitrogen portion of the air
trapped in the bomb to form
nitric
acid.
e
2
= The heat produced by the
formation of sulfuric acid
from the reaction of sulfur
dioxide, water and oxygen.
e
3
= Heat produced by the
heating wire and cotton
thread.
m = Mass of the sample.
These calculations are made in
calories, grams, and degrees
Celsius, and then converted to
other units if required.
Temperature Rise.
The 6200 Calorimeter produces a
corrected temperature rise reading
automatically. Corrections for heat leaks
during the test are applied. (For a complete
discussion of this process see Introduction
to Bomb Calorimetry, Manual No. 483M).
Energy Equivalent.
The energy equivalent (represented by
W in the above formula, or abbreviated as
EE) is determined by standardizing the
calorimeter as described in Appendix C -
Standardization. It is an expression of the
amount of energy required to raise the
temperature of the calorimeter one degree.
It is commonly expressed in calories per
degree Celsius. Since it is directly related to
the mass of the calorimeter, it will change
whenever any of the components of the
calorimeter (i.e. the bomb, bucket or amount
of water) is changed.
APPENDIX B CALCULATIONS
WT- e
1
– e
2
– e
3
m
B-1