Chapter 6 Self Test

What is wrong with this solution?

Problem

Consider the elementary gas phase reactions

Set up the equations to calculate the concentration of each species as a function of time in a constant volume batch reactor. The reaction is carried out isothermally.

Solution

A combined mole balance(1) and rate laws(2)

(3)  Stoichiometry

at t = 0  then  N_A = N_A0 and  

These equations will be typed into Polymath.

What five things are wrong with each of the first three steps of the multiple reaction algorithm?

Answer

Answer

(1)Mole Balance:  V missing on right hand side of each of the combined mole balance and rate law equations (1) through (4).

(2)Stoiciometry:  The gas reaction occurs in a constant volume rigid container, V = V₀. Therefore the equations [5) and (6)] for the concentration of the reacting species are not correct

(3)Rate laws, relative rates, and net rates:  The net rate of reaction is not correct for B,C, and D, i.e., equations (2), (3), and (4).

Correct Solutions

Since V = V₀

Mole Balance

(1)                                                     

(2)                                                     

(3)                                                    

(4)                                                    

Net Rates and Rate Laws

Net Rates

Species A

Species B

Species C

Species D

Summary

Stoichiometry

The pressure inside the vessel is

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