Example 2 Mass Balance on a Process with Reaction

3 Example 2 Mass Balance on a Process with Reaction 

Suppose an initially empty tank is filled with 1000 mol of ethane and the remainder with air. A spark is used to ignite this mixture and the following combustion reaction takes place  

Assume that the amount of air provides twice the stoichiometric requirement of oxygen for this reaction, and that air is composed of 79% nitrogen and the remainder oxygen. Suppose that the reaction reaches a 90% conversion. What is the composition of the mixture in the tank at the end of the reaction  

Our five mass balance equations, therefore, are as follows  

This set of nine equations reduces the degrees of freedom to 5 as no new variables have been introduced. 

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