Mothballs are composed primarily of the hydrocarbon naphthalene (C₁₀H₈). When 1.025 g of naphthalene burns in a bomb calorimeter, the temperature rises from 24.25 °C to 32.33 °C. Find ΔE_rxn for the combustion of naphthalene. The heat capacity of the bomb calorimeter, determined in a separate experiment, is 5.11 kJ/°C.

Key Concepts

Combustion Reaction

A combustion reaction is a chemical process in which a substance reacts rapidly with oxygen, producing heat and light. In the case of naphthalene, the combustion involves its reaction with oxygen to form carbon dioxide and water, releasing energy. Understanding this process is crucial for calculating the energy change associated with the reaction.

Calorimetry

Calorimetry is the science of measuring the heat of chemical reactions or physical changes. In this scenario, a bomb calorimeter is used to measure the heat released during the combustion of naphthalene. The temperature change observed in the calorimeter, along with its heat capacity, allows for the calculation of the energy change (ΔErxn) for the reaction.

Heat Capacity

Heat capacity is the amount of heat required to change the temperature of a substance by one degree Celsius. In the context of the bomb calorimeter, the heat capacity indicates how much energy is absorbed by the calorimeter for each degree of temperature increase. This value is essential for determining the total heat released during the combustion of naphthalene, as it directly relates to the temperature change observed.