Bomb Calorimeter Lab Report

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Abstract Bomb calorimeter was used in the experiment to determine the standard heat of combustion and formation of naphthalene. The heat capacity, C(s), of the bomb calorimeter obtained from a standard benzoic acid combustion was 10792.3±184.651 J/℃. Using this C(s), the enthalpy of combustion (∆Hcombust) of naphthalene was determined to be -5134.96±33.3433 kJ/mol. The final standard formation ((∆Hf, C10H8。) of naphthalene was 56.438±33.3433 kJ/mol, which was not very close to the theoretical value. Since only two runs were performed for each substance, more trials are needed to determine whether the error was random or systemic. Introduction The purpose of this experiment is to determine the standard heat of formation of naphthalene (figure 1) from its enthalpy of combustion. Standard heat of formation is the energy required for forming one mole of substance from its elements at standard conditions. In this experiment, …show more content…

A bomb calorimeter is composed of sample holder, ignition wire, bomb constructed of thick-walled stainless steel, platinum resistance thermometer, stirrer (and its motor), bucket, and insulated jacket (figure 2). The combustion reaction takes place inside the bomb, which is sealed with excess oxygen to allow the reaction to fully occur (3). The calorimeter bucket and the insulated outer jacket, where the bomb is placed in, minimize the heat exchange between the reaction and the environment. The former also contains known quantity of water that absorb the heat released by the bomb during the combustion. A platinum resistance thermometer that can be read to ±0.01℃ is used to measure the temperature of this water (1). Relevant Equations ∆Hrxn。= ∆Hf, products。 - ∆Hf, reactants。 (1) Temperature is continuously measured before, during, and after the standard reaction and reaction

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