Question

Consider the reaction

C₁₂H₂₂O₁₁ (s) + 12 O₂ (g) → 12 CO₂ (g) + 11 H₂O (l)

in which 10.3 g of sucrose, C₁₂H₂₂O₁₁, was burned in a bomb calorimeter with a heat capacity of 7.50 kJ/^oC (including its water). The temperature inside the calorimeter was found to increase by 21.7 ^oC. Based on this information, what is the heat of this reaction per mole of sucrose?

Enter your answer numerically, in terms of kJ/mol and to three significant figures.

Answer 1

heat of reaction = 5410 kJ

Explanation

heat absorbed = (heat capacity of calorimeter) * (rise in temperature)

heat absorbed = (7.50 kJ/^oC) * (21.7 ^oC)

heat absorbed = 162.75 kJ

heat released = -(heat absorbed)

heat released = -(162.75 kJ)

heat released = -162.75 kJ

mass sucrose = 10.3 g

moles sucrose = (mass sucrose) / (molar mass C₁₂H₂₂O₁₁)

moles sucrose = (10.3 g) / (342.3 g/mol)

moles sucrose = 0.030 mol

heat of reaction = (heat released) / (moles sucrose)

heat of reaction = (-162.75 kJ) / (0.030 mol)

heat of reaction = 5408.67 kJ/mol

heat of reaction = 5410 kJ      (with 3 significant figures)