Question

Hydrogen peroxide decomposes according to the following thermochemical reaction:
H2O2(l) → H2O(l) + 1/2 O2(g); ΔH = -98.2 kJ
Calculate the change in enthalpy, ΔH, when 1.00 g of hydrogen peroxide decomposes.

Answer 1

Answer: -2.89 kJ

• 34 g Hydrogen peroxide (1 mole) decompose to give -98.2 kJ energy as per the balanced chemical equation.
• (1 g H x 2) + (16 g O x 2) = 34 g H2O2.
• 34 g = -98.2 kJ
• divide both sides by 34
• 34 g / 34 = -98.2 kJ / 34
• 1 g = -2.89 kJ

Explanation: