ME 4611 Experiment 5 Bomb Calorimeter Experiment Yvette
ME 4611: Experiment 5 Bomb Calorimeter Experiment Yvette Triay - Leader Group 4
Purpose of the Experiment • To understand what a bomb calorimeter is, how to use it, and why it is useful • To determine thermal capacitance of the calorimeter • To determine the gross heat of combustion of the samples provided
What is a bomb-calorimeter? • Used to measure heat created by a sample burned under an oxygen atmosphere in a closed vessel, which is surrounded by water • Temperature differences in water are measured • Thermal capacitance and heat of combustions can be calculated with this data
Equipment: Parr Oxygen Bomb Calorimeter Picture taken from Parr Operating Manual: 1341 Oxygen Bomb Calorimeter [4]
Picture taken from Parr Operating Manual: 1341 Oxygen Bomb Calorimeter [4]
Thermodynamic Background 1 st Law of Thermodynamics Q=mcvΔT Q – heat of combustion mcv – thermal capacitance of the system ΔT – temperature rise
2 Tests Conducted 1) Known Fuel (Benzoic Acid) 2) Unknown Fuel • Calorimeter is considered thermodynamic system • Find thermal capacitance • Calorimeter capacitance remains constant • Find heat of combustion (mcv)calorimeter=Q/ΔT Q=(mcv)calorimeterΔT ★ Q is the heat of combustion of the fuel and the ignition wire.
Estimate thermal capacitance of the system (2 kg water and 3 kg stainless steel). (Thermal Capacitance)system = m(H 2 O)cv(H 2 O) + m(SS)cv(SS) (mcv)System = (2 kg)(4180* J/kg-K) + (3 kg)(470* J/kg-K) (mcv)System = 9770 J/K * See [1] of Appendices
Predict the temperature rise for 1 gram of Benzoic acid, which will be used as the calibration sample. Using Q = 26414* J/g [1], and plugging into the equation ΔT = Q/mcv ΔT = (26414 J/g)*(1 g) / (9770 J/K) ΔT = 2. 7 K * See [2] of Appendices
Appendices [1] Cengal, Yunus. Heat and Mass Transfer: Fundamentals & Application, 4 th Ed. [2] http: //www 2. stetson. edu/~wgrubbs/datadriven/fchen/strainchen. html [3] ME 4611 Laboratory Manual: Experiment 5 – Bomb Calorimeter Experiment [4] Parr Operating Manual: 1341 Oxygen Bomb Calorimeter [5] 1 st Law of Thermodynamics: (total energy entering a system ) – (total energy leaving a system) = (change in total energy of the system)
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