For $2 A + B P$ the initial rate of disappearance of $A$ , $- d [A] / d t$ , was measured: $[A] = 0.10$ , $[B] = 0.10 M$ : $2.60 \times 1 0^{- 4}$ ; $[A] = 0.20$ , $[B] = 0.10 M$ : $1.04 \times 1 0^{- 3}$ ; $[A] = 0.10$ , $[B] = 0.30 M$ : $7.80 \times 1 0^{- 4}$ (all in $M s^{- 1}$ ). The rate law is written for the rate of reaction $r$ (defined per unit stoichiometric coefficient). Find the initial rate of formation of $P$ , in units of $1 0^{- 3} M s^{- 1}$ , at $[A] = 0.25$ , $[B] = 0.40 M$ (two decimals).

Numerical answer type, answer in 10^-3 M s^-1, tolerance 0.02.

Answer: 3.25 10^-3 M s^-1

The data give order 2 in A (x4 on doubling) and order 1 in B (x3 on tripling). Reaction rate

r = - \frac{1}{2} d [A] / d t = 1.30 \times 1 0^{- 4}

in the first run, so

k = 1.30 \times 1 0^{- 4} / (0.1 0^{2} \times 0.10) = 0.13

. P forms at the rate

r

(coefficient 1):

r = 0.13 \times 0.2 5^{2} \times 0.40 = 3.25 \times 1 0^{- 3} M s^{- 1}