Question

Question 2:

a- Consider the elementary liquid-phase reaction: A ? B Taking place in A PFR. Determine the space-time taken to reach 80% conversion of A. The value of k is 2.3 s -1 .

b- The first-order reaction A? B is carried out in a batch reactor with k = 0.3 min-1 , what is the time (in min) required to consume 90% of A?

c- Plot the conversion X against time for the reaction described in b by assuming a first order reaction then a second order reaction.

Question 3: Describe in your own words a quantum chemistry procedure that can be applied to calculate reaction enthalpies.

Answer 1

a) mean residence time ( or space time) defined by ? = V/ v0

For first order PFR this can be written as

? = ? 1 /k * ln (1 ? X) .Solving this spact time = -1/2.3* ln(1-.8) =0.69975 min

b)Rate constant for first order ,rate constant(k) = ln{[A0]/[A]}/t

So time tequired t = ln{[A0]/[A]} /k = ln{100/(100-90) }/0.3 =7.675 min

C)To plot first order ratio use t = ln{[A0]/[A]} /k = put conversion 5 to 95 % and calculate time for all

For 5% conversion t= 0.17097 minute

15 %  conversion t= 0.5417 minute

30 %  conversion t= 1.1889 minute

45%  conversion t= 1.99279 minute

60%  conversion t= 3.054 minute

75%  conversion t= 4.62098minute

90%  conversion t= 7.675 minute

95%  conversion t= 9.9857minute