C The initial rate of reaction is faster than the average ra

C. The initial rate of reaction is faster than the average rate of reaction 7. (10 points) Consider the first-order reaction 2N,Os(g)-4NO-(9)+O49). N2Os Initial rate (M/\'S) 0.00270 0.400 Complete one of the following. If you answer both, only part (a) will be graded. a. Calculate the half-life (in s). b. If the initial concentration of N2Os is 0.850M, calculate the molarity of N Os after 25s. In Ca Assu me 00879 s to 3346 K mls 2y

Solution

According to chegg rules we have to answer only first one problem

Half time:

The time in which the amount of sample is half decay is called half time.

For a first order reaction    

A---- > products ,  

rate = k[A]:

0.00270 = k [0.400]

k = 0.00675 /s

t_½ = 0.693 / k

= 0.693 / 0.00675 /s

= 102.67 s

= 1.71 min

For first order;

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

In [A] = - 0.00675 s* 25s + ln [0.850]0

In [A] = -0.16875 -0.163

In [A]= - 0.33175

[A]= 0.718 M