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Ch.5 - Thermochemistry
Brown - Chemistry: The Central Science 15th Edition
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970Non è quello che usi tu?Cambia libro di testo
Capitolo 5, Problema 57a

A 2.200-g sample of quinone (C6H4O2) is burned in a bomb calorimeter whose total heat capacity is 7.854 kJ/°C. The temperature of the calorimeter increases from 23.44 to 30.57 °C. (a) What is the heat of combustion per gram of quinone?

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Calculate the temperature change (\( \Delta T \)) of the calorimeter by subtracting the initial temperature from the final temperature: \( \Delta T = 30.57 \, ^\circ\text{C} - 23.44 \, ^\circ\text{C} \).
Use the formula for heat absorbed by the calorimeter: \( q = C_{\text{cal}} \times \Delta T \), where \( C_{\text{cal}} \) is the heat capacity of the calorimeter (7.854 kJ/°C).
Substitute the values into the formula to find the total heat absorbed by the calorimeter: \( q = 7.854 \, \text{kJ/°C} \times \Delta T \).
Determine the heat of combustion per gram of quinone by dividing the total heat absorbed by the mass of the quinone sample: \( \text{Heat of combustion per gram} = \frac{q}{\text{mass of quinone}} \).
Substitute the mass of the quinone sample (2.200 g) into the equation to find the heat of combustion per gram.

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Heat Capacity

Heat capacity is the amount of heat energy required to change the temperature of a substance by one degree Celsius. In calorimetry, the heat capacity of the calorimeter is crucial for determining the total heat absorbed during a reaction. It allows us to calculate the heat released by the combustion of a sample by multiplying the heat capacity by the change in temperature.
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Calorimetry

Calorimetry is the science of measuring the heat of chemical reactions or physical changes. In a bomb calorimeter, the heat released from a combustion reaction is measured by observing the temperature change in the calorimeter. This technique is essential for determining the energy content of fuels and other substances, such as quinone in this case.
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Constant-Volume Calorimetry

Heat of Combustion

The heat of combustion is the amount of energy released when a substance is completely burned in oxygen. It is typically expressed in joules or kilojoules per gram. To find the heat of combustion per gram of quinone, the total heat released during the combustion process is divided by the mass of the sample, providing a measure of its energy content.
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Combustion Apparatus
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