Iodine combines to form I2 in liquid propane solvent with a constant of 1,5 x 10^10 L/mol. The rate is 2nd order. Since the reaction occurs quickly, a flash of light creates an I concentration of .0100M. How long will it take for 95% of the atoms to form I2?
This must use a second order rate equation, but I cannot get 1.0x10^-7 s which is the answer.
I assume 1.0x10^-7 s = seconds.
To solve this problem, we need to use the second-order rate equation that relates the concentration of Iodine and the time it takes for the reaction to occur:
1/[I]t = 1/[I]0 + kt
Where:
[I]t is the concentration of Iodine at time t
[I]0 is the initial concentration of Iodine
k is the rate constant
t is the time
Given:
Constant (k) = 1.5x10^10 L/mol
Initial concentration ([I]0) = 0.0100 M
Final concentration ([I]t) = 0.9500 M (95% of the initial concentration)
We can rearrange the equation to solve for t:
t = 1 / ( k * ([I]t - [I]0 ) )
Now let's plug in the values:
t = 1 / ( 1.5x10^10 L/mol * (0.9500 M - 0.0100 M) )
t ≈ 1.0x10^-7 s
So the answer is indeed approximately 1.0x10^-7 seconds.
If you are getting a different answer, please double-check the values you have used for the rate constant (k) and the concentrations ([I]t and [I]0). Ensure that the units are consistent (e.g., if the concentration is given in M, the rate constant should be in L/mol). Also, verify that you have correctly rearranged the equation and carried out the calculations accurately.