Question
Part B
Exp [A] [B] Rate (1/M·s)
1 .0319 .0520 4.1 E -3
2 .0319 .104 4.1 E -3
3 .0639 .104 1.63 E -2
From the above data, find the order of the reaction with respectto A:
the order with respect toB:
What is the value of k from the above data? Include correctunits.
Explanation / Answer
From the above data (1) Keeping the conc. of [A] constant , when conc. of [B ] is doubled , the rate remains the same i.e., rate [ B ] 0 So, the order with respect to B is zero So, the order with respect to B is zero (2) Keeping the conc. of [B] constant , when conc. of[ A ] is doubled , the rate is four times i.e., rate [ A ] 2 So, the order with respect to A is two So, rate Equation : dx / dt = K [ A ]2 [ B ]0 ; where K = rate constant So, the order with respect to A is two So, rate Equation : dx / dt = K [ A ]2 [ B ]0 ; where K = rate constant Let us take [ A ] = 0.0319 M rate , dx / dt = 4.1 * 10 -3 M-1 s -1 dx / dt = K [ A ]2 4.1 * 10 -3 M -1 s-1 = K ( 0.0319 M ) 2 K = 4.029 L / mol / s
Note : Be sure that the units of rate is M /s not 1 / M - s If the units of rate are taken as M / s , Then the units of Kare 1 / M - s K = 4.029 L / mol / s
Note : Be sure that the units of rate is M /s not 1 / M - s If the units of rate are taken as M / s , Then the units of Kare 1 / M - s