Question

for question 3 im getting 96.234 sec but it says its wrong but close to the answer.
for activation energy.. i get 24.6 kj/mol but its wrong

3) You mix together in the proper manner the following VOLUMES:
0.0100 M Potassium iodide...14.7 mL
0.0010 M Sodium thiosulfate...5.6 mL
Distilled water...22.7 mL
0.0400 M Potassium Bromate...11.7 mL
0.100 M Hydrochloric acid...5.6 mL
Using the rate constant and rate equation from problem 2),
exponent c is 1.92
exponent constant K 4.7125
CALCULATE the time to turn blue...__________________ sec (c)

4) A plot of log Rate vs 1/T gives a best straight line which goes through....
1/T = 0.00300, log rate = -4.46
and 1/T = 0.00352, log rate = -6.00.
CALCULATE:

The Slope of the line...is ________-2961.53_____ (d)

The Activation Energy (Ea) (Kj/mol)...________________(e)
thanks in advance

Answer 1

3) RATE = ([ Na2S2O3]/time) = k [I-]a [BrO3-]b [HCl]c

total volume =14.7 +5.6+22.7+11.7 + 5.6 = 60.3

i) 0.0100 M Potassium iodide...14.7 mL

so moles = molarity X volume = 0.01 X 14.7 /1000 =.147 / 1000

or concentration = moles / total volume =   0.000147X1000 / 60.3=0.00243 M

ii) 0.0010 M Sodium thiosulfate...5.6 mL

so moles = molarity X volume = 0.001 X 5.6 /1000 =

or concentration = moles / total volume =   0.0056   / 60.3 mL = 9.286 X 0^-5M

iii) Distilled water...22.7 mL
iv) 0.0400 M Potassium Bromate...11.7 mL

so moles = molarity X volume = 0.04 X 11.7 /1000 = 0.468 /1000

or concentration = moles / total volume =   0.468 X 1000/ 1000 X 60.3 mL =0.00776 M

v) 0.100 M Hydrochloric acid...5.6 mL

so moles = molarity X volume = 0.1 X 5.6 /1000 = 0.56 / 1000

or concentration = moles / total volume =   0.56 X1000 / X 1000 60.3 mL =0.00928 M

Rate constant = K = 4.7125 (given)

RATE = ([ Na2S2O3]/time) = k [I-] [BrO3-]⁰ [HCl]² = 9.286 X 10^-5/ time = 4.7125 X 0.00243 X (0.00928)²

Time =9.286 X 10^-5/ 4.7125 X 0.00243 X 0.00928 X 0.00928

= 94.16 seconds