Initial‑rate data at a certain temperature

Question

Initial‑rate data at a certain temperature is given in the table for the reaction N2O3(g)⟶NO(g)+NO2(g)

[𝐍2𝐎3]0(𝐌) initial rate (M/s)

0.100	0.540
0.200	1.080
0.300	1.620

Determine the value and units of the rate constant.

Answer 1

Doubling [N₂O₃] from 0.1 M to 0.2 M also doubles the rate from 0.540 to 1.08.

Tripling the [N₂O₃] from 0.1 M to 0.3 M also triples the rate from 0.540 to 1.60.

This behavior tells us that the reaction is FIRST order in [N₂O₃].

The rate law for this first order reaction is ..

Rate = k[N2O3]

To find the value of k, simply use the data from the table and solve for k:

0.540 M/s = k [ 0.100 M]

k = 0.540 M/s / 0.100 M

k = 5.4 s^-1