Calculate the amount (mass)of acetaldehyde (C₂H₄O, molar mass = 44.0526 g mol^-1)that causes a bomb calorimeter with a heat capacity of 12.91 kJ °C^-1 to have a temperature increase from 27.8 °C to 41.7 °C. The $\Delta$_rU for the combustion of acetaldehyde is -1166.9 kJ mol^-1.

Question

Quizplus · Accepted Answer

The temperature change is 41.7 °C - 27.8 °C = 13.9 °C. The heat absorbed by the calorimeter is q = C * ΔT = 12.91 kJ/°C * 13.9 °C = 179.449 kJ. Using the reaction energy, -1166.9 kJ/mol, the moles of acetaldehyde combusted is 179.449 kJ / 1166.9 kJ/mol = 0.1538 mol. The mass is then 0.1538 mol * 44.0526 g/mol = 6.77 g.

Calculate the Amount (Mass)of Acetaldehyde (C2H4O, Molar Mass = 44 Δ\DeltaΔ

Calculate the Amount (Mass)of Acetaldehyde (C₂H₄O, Molar Mass = 44 $\Delta$