Part A – Determining the Rate Law The reaction to be studied in this experiment
ID: 1016760 • Letter: P
Question
Part A – Determining the Rate Law
The reaction to be studied in this experiment is the redox reaction. With three reactants, we expect a rate law of the form
6 I- (aq) + BrO3- (aq) + 6 H+ (aq) à 3 I2 (aq) + Br- (aq) + 3 H2O (l).
rate = k [I-]x[BrO3-] y[H+] z.
If thiosulfate ion is present in the reaction rmixture:
I2 (aq) + 2 S2O32- (aq) à 2 I- (aq) + S4O62- (aq).
1. A student mixed the following reactants, using the general procedure for the experiment: 10.0 mL 0.10 M KI, 10.0 mL 0.0010 M Na2S2O3, 10.0 mL 0.040 M KBrO3, and 10.0 mL 0.10 M HCl.
By using the dilution equation calculate the concentrations of each reactant in the mixture:
[I- ] = ________ [BrO3 - ] = ________ [H+ ] = ________
2. The concentration of the thiosulfate ion is the same in every reaction. Calculate the molarity of the thiosulfate ion initiailly present in each reaction mixture.
Explanation / Answer
1. A student mixed the following reactants, using the general procedure for the experiment: 10.0 mL 0.10 M KI, 10.0 mL 0.0010 M Na2S2O3, 10.0 mL 0.040 M KBrO3, and 10.0 mL 0.10 M HCl.
By using the dilution equation calculate the concentrations of each reactant in the mixture:
[I- ] = ________ [BrO3 - ] = ________ [H+ ] = ________
Solution :-
Total volume = 10 ml + 10 ml +10 ml + 10 ml = 40 ml
Calculating the molarity of each ion using the M1V1=M2V2
[I-] = 0.10 M * 10 ml / 40 ml = 0.025 M
[BrO3-] = 0.04 M * 10 ml / 40 ml = 0.01 M
[H+] = 0.10 M * 10 ml / 40 ml = 0.025 M
2. The concentration of the thiosulfate ion is the same in every reaction. Calculate the molarity of the thiosulfate ion initiailly present in each reaction mixture.
Solution :-
Molarity of the thiosulfate = 0.00100 M * 10 ml / 40 ml = 0.00025 M