Iron(II) ion is oxidized by hydrogen peroxide in acidic solution H2O2(aq) + 2Fe2+(aq) + 2H+(aq)  →  2Fe3+(aq) + 2H2O(l) The rate law  for the reaction is  Rate = k[H2O2][Fe2+] What is the order of reaction with respect to  H2O2, Fe2+ and H+,respectively? What is the overall order of reaction?

A proposed mechanism for the decomposition of hydrogen peroxide consists of three elementary steps: (1) H₂O2(g) →>> 2OH(g) (2) H₂O2(g) + OH(g) → H₂O(g) + HO₂(g) (3) HO₂(g) + OH(g) → H₂O(g) + O₂(g) If the rate law for the reaction is first order in H₂O2, which step in the mechanism is the rate-determining step? O Step 1 O None of the steps O Step 3 O Impossible to determine Steps 1 and 2 O All of the steps O Step 2 Hint: The slowest step in a mechanism determines the rate law. From each elementary reaction we can write a rate-law expression. Submit Question

4. The rate law for the reaction H₂ (g) + I₂ (g) → 2 HI (g) was determined to be rate = k [H₂] [1₂], which led to a simple single-step bimolecular mechanism where an H₂ molecule simply collided with an I₂ molecule. In the 1960s, though, different teams found spectroscopic evidence for this mechanism: (1) (2) (3) I₂ (g) →21 (g) H₂(g) + I (g) → H₂I (g) H₂I (g) + I (g) → 2 HI (g) (fast) (fast) (slow) Show that this mechanism is consistent with the rate law: rate = k [H₂] [1₂]. To do this, assign individual rate constants for ALL forward and reverse reactions in the mechanism (I'm guessing k₁, k-1, k2, k-2 and k3). Then show that the overall rate law from combining individual rate laws for the mechanism steps yields rate = (some combination of k's) [H₂] [1₂], and thus k= (some combination of k's). Remember that there should be no reaction intermediates in the rate law, only reactants. \

5. You studied the chemical reaction, 2NO2(g) → 2NO(g) + O2(g), at 25°C by monitoring the concentration of NO2(g) as a function of time and constructed the following graph. y= 0.5408x + 125.0 R2=0.998 Time (s) What is the rate constant for this reaction at 25°C? Include the proper units. (W/T) [(3)ONI/T