Question

At 25 °C, the decomposition of dinitrogen pentoxide, N 2 O 5 ( g ), into NO 2 ( g ) and O 2 ( g ) follows first-order kinetics with k = 3.4 * 10 -5 s -1 . A sample of N 2 O 5 with an initial pressure of 760 torr decomposes at 25 °C until its partial pressure is 650 torr. How much time (in seconds) has elapsed

Answer 1

he integrated rate law for a first-order reaction is as follows:

In[A]t = -kt + In [A]0

where:

[A]t = concentration at time t

k = rate constant

t = time

[A]0 = initial concentration

The moles are proportional to pressure so we can use the pressure in the equation.