Question

1.) A student enters the lab and performs Experiment 14 as written. In the procedure for "Experiment 1" on p. 230 of the lab manual, the student records the concentration of the stock solution of H₂O₂ to be 0.965 M. The student proceeds to prepare the reaction solution as stated in the lab manual: They add 10.0 mL of 0.10 M potassium iodide and 15.0 mL of distilled water to their flask. They then add 5.0 mL of the stock H₂O₂ solution and mix the solution to initiate the reaction.

Calculate the molarity of I^- in the initial reaction solution. Do not include the units with your answer.

2.) Given the equation: rate = k[H₂O₂]^m[I^-]ⁿ
Which of the following statements is (are) true about the orders, m and n?

	A.	m and n must be determined by experiment
	B.	m and n are equal to each other in all cases.
	C.	m and n are independent from the molar coefficients of the reactants in the balanced chemical equation.
	D.	m and n are equal to the molar coefficients of H2O2 and I- in the balanced chemical reaction, respectively.

Answer 1

• Millimoles of I-= Molarity X volume of solution in ml = 0.10 M X 10.0 mL = 1 mmol • final volume of solution = (10.0 + 15.0 +5.0) mL = 30.0 mL • Molanity of I' in the solution initial reaction . mmoles of I- Volume of solution in ml I samol 0.033 M 30.0 mL

2) The correct statements are (A) and (C).

Explanation: The order of a reaction is an experimental quantity. It is determined by the mechanism of a reaction. It may or may not be equal to the respective stoichiometric coefficients of the reactants in a balanced chemical equation.