The calibration factor of a bomb calorimeter was calculated to be 10.27 kJ K^-1. Calculate the internal energy change of combustion $\Delta_{c} U$ for glucose (M_r = 180.16) if the combustion at 298 K of 1.228 g caused a temperature rise of 1.847 K.

Question

Quizplus · Accepted Answer

The internal energy change of combustion is calculated using the formula: $\Delta_{c} U = -C \times \Delta T$, where $C$ is the calibration factor and $\Delta T$ is the temperature change. Substituting the given values: $\Delta_{c} U = -10.27 \, \text{kJ K}^{-1} \times 1.847 \, \text{K} = -18.96 \, \text{kJ}$. Since the mass of glucose is 1.228 g, we convert this to moles: $1.228 \, \text{g} / 180.16 \, \text{g/mol} = 0.00682 \, \text{mol}$. The internal energy change per mole is $-18.96 \, \text{kJ} / 0.00682 \, \text{mol} = -2783 \, \text{kJ/mol}$.

The Calibration Factor of a Bomb Calorimeter Was Calculated to Be