Question

1.When the reaction between bromate ions and bromide ions was studied, the following tabulated data was obtained:

BrO3 + 5Br + 6H ---> 3Br2 + 2H2O

Exp. #	Volume of .4M BrO3	Volume of 0.4M Br	Volume of 0.4M H	Volume of water	Reaction time
1	10.0 mL	10.0 mL	10.0 mL	10.0 mL	121 seconds
2	20.0 mL	10.0 mL	10.0 mL	0 mL	124 seconds

In order to determine the reaction order of bromate, calculate the following:

1. Initial concentrations of bromate ion

Reaction #1 Reaction #2

2. Initial reaction rate with respect to bromate disappearance

Reaction #1 Reaction #2

3. Ratio of reaction #1 rate/reaction #2 rate

4. Log of reaction rate ratio

5. Ratio of concentration of bromate ion, reaction #1/reaction #2

6. Log of concentration ratio

7. Reaction order for bromate ion

Answer 1

1. Initial concentration of bromate ion

Reaction #1          0.4 M x 10 ml/40 ml = 0.1 M

Reaction #2          0.4 M x 20 ml/40 ml = 0.2 M

2. Initial reaction rate with respect to bromate disappearence

Reaction #1 : [0.1 M - (0.4 M x 10 ml/40 ml x 5)/121 s = 6.61 x 10^-4 M/s

Reaction #2 : [0.2 M - (0.4 M x 10 ml/40 ml x 5)/124 s = 1.45 x 10^-3 M/s

3. Ratio of reaction #1 rate/reaction #2 rate = 6.61 x 10^-4/1.45 x 10^-3 = 0.456

4. Log of reaction rate ratio = log(0.456) = -0.3410

5. ratio of conc. = (reaction #1/reaction #2) = (0.1/0.2) = 0.5

6. log of ratio of conc. of bromate = log(0.5) = -0.3010

7. Reaction order for bromate ion = (-0.3410/-0.3010) = 1