# Problem: Iodine atoms will combine to form I2 in liquid hexane solvent with a rate constant of 1.5 x 1010 L/mol•s. The reaction is second order in I. Since the reaction occurs so quickly, the only way to study the reaction is to create iodine atoms almost instantaneously, usually by photochemical decomposition of I2. Suppose a flash of light creates an initial [ I ] concentration of 2.00 x 10−2 M. How long will it take for 92% of the newly created iodine atoms to recombine to form I2?

96% (90 ratings)
###### FREE Expert Solution

We’re being asked to determine the time needed for 92% of I atoms to recombine to I2 given the following second-order reaction:

2 I  I2

The integrated rate law for a second-order reaction is as follows:

$\overline{)\frac{\mathbf{1}}{{\mathbf{\left[}\mathbf{A}\mathbf{\right]}}_{\mathbf{t}}}{\mathbf{=}}{\mathbf{kt}}{\mathbf{+}}\frac{\mathbf{1}}{{\mathbf{\left[}\mathbf{A}\mathbf{\right]}}_{\mathbf{0}}}}$

where:

[A]t = concentration at time t

k = rate constant

t = time (unknown)

[A]0 = initial concentration

96% (90 ratings) ###### Problem Details

Iodine atoms will combine to form I2 in liquid hexane solvent with a rate constant of 1.5 x 1010 L/mol•s. The reaction is second order in I. Since the reaction occurs so quickly, the only way to study the reaction is to create iodine atoms almost instantaneously, usually by photochemical decomposition of I2. Suppose a flash of light creates an initial [ ] concentration of 2.00 x 10−2 M. How long will it take for 92% of the newly created iodine atoms to recombine to form I2?

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Integrated Rate Law concept. You can view video lessons to learn Integrated Rate Law. Or if you need more Integrated Rate Law practice, you can also practice Integrated Rate Law practice problems.

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Based on our data, we think this problem is relevant for Professor Hershberger-Kilyanek's class at UARK.