Ethane gas, or dicarbon hexahydride, undergoes combustion to produce carbon dioxide gas and water vapor.

Question

A.) What mass of the un named reactant is required to react with moles of ethane?

B.) How many molecules of the porduct, with the smaller percent composition of the non-oxide component, are produced if the reaction only goes 57.8 percent to completion?

Answer 1

You didn't provide the moles of ethane. The un-named reactant is oxygen.
For the second part, here is an example. Just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html