Multiple Choice
What is the specific heat capacity of the bomb calorimeter if burning 100.0 moles of sulfamic acid results in a temperature increase of 4.57°C, given that the ΔErn for the combustion of 1 mole of sulfamic acid is -686.2 kJ?
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8. Thermochemistry
Constant-Volume Calorimetry
Multiple Choice
A 6.55 g sample of aniline (C6H5NH2, molar mass = 93.13 g/mol) was combusted in a bomb calorimeter. If the temperature rose by 32.9°C, use the information below to determine the heat capacity of the calorimeter. The balanced reaction is: 4 C6H5NH2(l) + 35 O2(g) → 24 CO2(g) + 14 H2O(g) + 4 N2(g). Given that the standard enthalpy of combustion for aniline is -3170 kJ/mol, what is the heat capacity of the calorimeter?
A
5.89 kJ/°C
B
6.45 kJ/°C
C
7.02 kJ/°C
D
8.15 kJ/°C
Verified step by step guidance1
Calculate the number of moles of aniline combusted using its mass and molar mass. Use the formula: \( \text{moles} = \frac{\text{mass}}{\text{molar mass}} \).
Determine the total heat released during the combustion of the aniline sample using the standard enthalpy of combustion. Multiply the moles of aniline by the standard enthalpy of combustion: \( q = \text{moles} \times \Delta H_{\text{combustion}} \).
Recognize that the heat released by the combustion of aniline is absorbed by the calorimeter, causing the temperature to rise. Therefore, the heat absorbed by the calorimeter \( q_{\text{calorimeter}} \) is equal to the heat released by the reaction.
Use the formula for heat absorbed by the calorimeter: \( q_{\text{calorimeter}} = C_{\text{calorimeter}} \times \Delta T \), where \( C_{\text{calorimeter}} \) is the heat capacity of the calorimeter and \( \Delta T \) is the change in temperature.
Rearrange the formula to solve for the heat capacity of the calorimeter: \( C_{\text{calorimeter}} = \frac{q_{\text{calorimeter}}}{\Delta T} \). Substitute the values for \( q_{\text{calorimeter}} \) and \( \Delta T \) to find the heat capacity.
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