Question

part b: What is the average reaction rate between 500. and 1200. s ?

part c : What is the instantaneous rate of the reaction at t=800. s ?

An average reaction rate is calculated as the change in the concentration of reactants or products over a period of time in the course of the reaction. An instantaneous reaction rate is the rate at a particular moment in the reaction and is usually determined graphically.

The reaction of compound A forming compound B was studied and the following data were collected:

Time (s )	[A] (M )
0.	0.184
200.	0.129
500.	0.069
800.	0.031
1200.	0.019
1500.	0.016

Answer 1

Average rate of reaction = - [A] / t = - ( [A] _{t= 1200 s} - [A] _{t= 500 s} ) / 1200 s - 500 s

$\therefore$ Average rate of reaction = - ( 0.019 M - 0.069 M / 700 s) = 0.05 M / 700 s = 7.14 x 10 ^-05 M/s.

From graph we can calculate instantaneous rate of reaction.

Scale A- axis Y-as 62 1400 400 200 Time C

Instantaneous rate of reaction at t= 800 s = - slope = - ( 0.01 M - 0.06 M) / 1060 s - 450 s

= 0.05 M / 610 s

= 8.20 x 10 ^-05 M/s