Solution Found!
The compound AX2 decomposes according to the equation
Chapter 16, Problem 12P(choose chapter or problem)
Problem 12P
The compound AX2 decomposes according to the equation 2AX2( g) →2AX( g) + X2( g). In one experiment, [AX2] was measured at various times and these data were obtained:
Time (s) |
[AX2] (mol/L) |
0.0 |
0.0500 |
2.0 |
0.0448 |
6.00 |
0.0300 |
8.0 |
0.0249 |
10.0 |
0.0209 |
20.0 |
0.0088 |
(a) Find the average rate over the entire experiment.
(b) Is the initial rate higher or lower than the rate in part (a)? Use graphical methods to estimate the initial rate.
Questions & Answers
QUESTION:
Problem 12P
The compound AX2 decomposes according to the equation 2AX2( g) →2AX( g) + X2( g). In one experiment, [AX2] was measured at various times and these data were obtained:
Time (s) |
[AX2] (mol/L) |
0.0 |
0.0500 |
2.0 |
0.0448 |
6.00 |
0.0300 |
8.0 |
0.0249 |
10.0 |
0.0209 |
20.0 |
0.0088 |
(a) Find the average rate over the entire experiment.
(b) Is the initial rate higher or lower than the rate in part (a)? Use graphical methods to estimate the initial rate.
ANSWER:Solution 12P
Step 1
(a) Here we have to find the average rate over the entire experiment.
The compound AX2 decomposes according to the equation 2AX2( g) →2AX( g) + X2( g). In one experiment, [AX2] was measured at various times and these data were obtained:
Time (s) |
[AX2] (mol/L) |
0.0 |
0.0500 |
2.0 |
0.0448 |
6.00 |
0.0300 |
8.0 |
0.0249 |
10.0 |
0.0209 |
20.0 |
0.0088 |
In the above table it is given that, at time t = 0, AX2 =0.0500 mol/L and at time t = 20.0,
AX2 =0.0088 mol/L .
The average rate for the entire process is proportional to the slope of the line connecting these two points i.e AX2 at t initial to AX2 at t final.
Rate of reaction is defined as the change in concentration of the product with time. If a reactant is used, the rate is the negative of the concentration of the reactant.
Rate can be calculated as Rate = -(½ ) [AX2]/
= -(½ ) (0.0088 M-0.0500 M) / (20.0 s - 0 s)
= 0.0010 M/s
(*Here the ½ factor is used as the stoichiometric coefficient of 2 for AX2 in the reaction)
Thus the average rate of reaction is found to be 0.0010 M/s.