Hydrogen peroxide decomposes to water and oxygen at constant pressure by the following reaction: 2H₂O₂ (l) → 2H₂O (l) + O₂ (g) △H = -196 kJ
Calculate the value of q (kJ) in this exothermic reaction when 1.50 g of hydrogen peroxide decomposes at constant pressure?

Question

Quizplus · Accepted Answer

The molar mass of H₂O₂ is 34.01 g/mol. For 1.50 g of H₂O₂, moles = 1.50 g / 34.01 g/mol = 0.0441 mol. The reaction releases 196 kJ for 2 moles of H₂O₂, so for 0.0441 mol, q = (196 kJ / 2 mol) * 0.0441 mol = -4.32 kJ.

Hydrogen Peroxide Decomposes to Water and Oxygen at Constant Pressure