Question

a certain reaction is first order in h₂ and first order in i₂. use this information to complete the table below. round each of your answers to 3 significant digits.
h₂ i₂ initial rate of reaction
2.03 m 1.22 m 3.00 m/s
2.03 m 3.67 m m/s
8.54 m 0.290 m 3.00 m/s

Explanation:

Step1: Determine the rate - law expression

Since the reaction is first - order in $H_2$ and first - order in $I_2$, the rate - law is $r = k[H_2][I_2]$. Using the first row of data ($[H_2]=2.03\ M$, $[I_2]=1.22\ M$, $r = 3.00\ M/s$), we can find the rate constant $k$.
$k=\frac{r}{[H_2][I_2]}=\frac{3.00\ M/s}{2.03\ M\times1.22\ M}\approx1.21\ M^{-1}s^{-1}$

Step2: Calculate the rate for the second row

For the second row, $[H_2]=2.03\ M$ and $[I_2]=3.67\ M$. Using the rate - law $r = k[H_2][I_2]$ and the value of $k$ we just found.
$r=(1.21\ M^{-1}s^{-1})\times2.03\ M\times3.67\ M$
$r = 1.21\times2.03\times3.67\ M/s\approx9.03\ M/s$

Answer:

$9.03$