Assignment on Thermodynamics PDF

Running head: Thermodynamics 1
THERMODYNAMICS
Name of Student
Institution Affiliation

THERMODYNAMICS 2
Discussions
This is an experiment carried out to measure the enthalpy change whenever a substance is
burned. In order to measure the capacity of heat of the bomb calorimeter, a weighted mass of a
standard compound is first burned. This must be a substance with a known enthalpy of
combustion. The most commonly used substance for calibration is the Benzoic acid (C6 H5 CO2
H) since it is a crystalline that can be acquired in high purity. Benzoic acid was the reference
material for this experiment. Its combustion in a bomb calorimeter releases 26.38 kJ of heat per
gram (Washburn, 2011). During the process of calibration, a known amount of heat is introduced
to the calorimeter through the combustion of benzoic acid. This process releases energy that is
equivalent to the calorimeter for a specific rise in temperature. When in need of testing an
unknown sample, the heat capacity of the bomb calorimeter has to be known. The sample is the
burned, the energy released is then absorbed within the calorimeter and the resultant change in
temperature is taken.
The data from the test results for each runs is recorded. There is need to find an accurate value
that will represent the overall change in temperature that resulted from the burning reaction. The
data can then be used to calculate the system heat capacity, C, in regard to the calibration runs of
the benzoic acid (Dickinson, 2015).
Conclusion
The amount of heat that is released from the any given sample can be calculated by observing the
rise in temperature for the water as well as knowing the energy that is equivalent to the
calorimeter. The results of the test are expressed in (cal/g) calories per gram.

THERMODYNAMICS 3
References
Washburn, E. W. (2011). Standard states for bomb calorimetry. J. Res. Natl. Bur. Stand.(US), 10,
525-558.
Dickinson, H. C. (2015). Combustion calorimetry and the heats of combustion of cane sugar,
benzoic acid, and naphthalene (Vol. 11, No. 2). US Government Printing Office.