2 H2O2(aq) → 2 H2O(l) + O2(g) 2. Hydrogen peroxide, H2O2, decomposes according to the equation above — Kinetics Chemistry Question

1 point is earned for correctly representing products as H₂O and O₂ molecules.
1 point is earned for atom balance.

(i) This reaction is exothermic because the products have lower potential energy than the reactants. Thus, the system has lost potential energy, releasing heat.
1 point is earned for indication that the reaction is exothermic, with a valid justification.

(ii) The curve for the catalyzed reaction has the reactants and products at the same energy levels as the original curve, and a lower activation energy than the original curve.
1 point is earned for a correct curve.

(i) mass O₂ = 43.19 g − 42.58 g = 0.61 g
moles O₂ = 0.61 g O₂ × (1 mol O₂ / 32.00 g) = 0.019 mol O₂
1 point is earned for the correct answer.

(ii) mass H₂O₂ = 0.019 mol O₂ × (2 mol H₂O₂ / 1 mol O₂) × (34.02 g H₂O₂ / 1 mol H₂O₂) = 1.3 g H₂O₂
1 point is earned for the correct answer.

Less than.
The decrease in mass becomes smaller over every subsequent 10-second interval. This decreasing trend would continue in the second minute.
1 point is earned for the correct choice with a valid explanation.

Disagree.
If the reaction were zeroth-order, the rate of mass loss (which corresponds to the rate of reaction) would be constant until the reactant was consumed. However, the data show that the rate of mass loss from beaker 2 is not constant.
1 point is earned for disagreement and a valid justification.

Agree.
The calculated amount of O₂ produced is based on the change in mass, and in this case some of the change in mass is due to loss of solution rather than production of O₂.
1 point is earned for agreement and a valid justification.

(NH₄)₂S₂O₈ + 2 H₂O → H₂O₂ + 2 NH₄HSO₄
OR
(NH₄)₂S₂O₈ + 2 H₂O → H₂O₂ + 2 NH⁴⁺ + 2 HSO^4-
OR
S₂O₈ 2− + 2 H₂O → H₂O₂ + 2 HSO4−
1 point is earned for a correct balanced equation.