The gas-phase reaction obeys the rate law

CHEMISTRY · Single correct · A Level · Chemistry · Rate equations · Rate equations

Problem

The gas-phase reaction

A + 2B + C \to \text{products}

obeys the rate law

\text{rate} = k[A]^2[B][C]^0

. In Experiment 1, the initial rate is

2.0\times 10^{-5}\,\text{M}\cdot\text{s}^{-1}

when

[A]=0.10\,\text{M}

[B]=0.20\,\text{M}

, and

[C]=0.50\,\text{M}

25\,^\circ\text{C}

. In Experiment 2, the temperature is raised slightly, but

k

is assumed unchanged over this small range. Simultaneously,

[A]

is tripled,

[B]

is halved, and

C

is omitted from the reaction mixture. What is the predicted initial rate in Experiment 2? (a)

3.0\times 10^{-5}\,\text{M}\cdot\text{s}^{-1}

(b)

4.5\times 10^{-5}\,\text{M}\cdot\text{s}^{-1}

(c)

9.0\times 10^{-5}\,\text{M}\cdot\text{s}^{-1}

(d)

1.8\times 10^{-4}\,\text{M}\cdot\text{s}^{-1}