Reactions where one product is the reactant for another reaction

[miniradman]

Hello

I'm not sure if this belongs in this forum or the homework forum, but I have a quick question about selectivity and yield in reactions where one product is made, and that product returns to one of the reactants to create another separate reaction.

for example:

$C_{6}H_{12} + H_{2}O \Rightarrow 6CO + 12H_{2}$
$C_{6}H_{12} + H_{2} \Rightarrow C_{6}H_{14}$

As you can see, the one of the products in the first reaction is involved with the second reaction. When calculating things such as which is the limiting reagent or which is the excess reagent, do we take the 2nd reaction into account? Given values for number of moles for the reactants from equation 1 and the selectivity and yield of one of the products from equation 1, how can we use these values to find number of moles of product?

 

[jbsteele]

The selectivity and yield are typically calculated from the ratio of products formed from the first reaction equation. However, they can also be used to calculate the number of moles of product formed in the second reaction equation by taking into account the ratio of reactants and products used in both equations. You can then use the same selectivity and yield values to determine the amount of product produced in the second equation.